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Year 5: Pathology > Micro > Flashcards

Micro Flashcards

1
Q

SUMMARY CARD:

What is a mycobacterium?
How does it stain?

Clue: AFB

A

Mycobacterium = non-motile rods, obligate aerobes, acid-fast bacteria (AFB)

Gram +ve (but does not take up the gram stain well) therefore, use AFB staining:

  • Auramine = SCREENING test: flourescent stain –> yellow (more sensitive but less specific than ZN)
  • Ziehl-Neelson stain: carbol fuschin & methylene blue –> AFB go red on a blue background
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2
Q

SUMMARY CARD:

What are the different types of mycobacterium?

TB, avium complex, abscessus, marinum, ulcer, leprae

A
  1. Mycobacterium tuberculosis: caeseating granulomas (cottage-cheese central necrosis), Mx = RIPE
  2. Mycobacterium avium complex: slow-growing, associated with pre-existing lung disease (e.g.immunocompromised/structural lung problem), found in food / water/ soil; types = intracellulare, avium and chimaera
  3. Mycobacterium abscessus complex: rapid-growing and more common in CF, Mx = macrolide (e.g. clarithyromycin); types = abscessus, massilense, boleletii
  4. Mycobacterium marinum: live in water; exposure to fish –> swimming pool granulomas (subcutaneous nodules)
  5. Mycobacterium ulcerans: more common in tropics / Australia –> buruli ulcer (chronic progressive painless ulcer)
  6. Mycobacterium leprae (leprosy): more common in Africa, Sx = nerve damage (peripheral neuropathy), depigmentation of the skin
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3
Q

SUMMARY CARD:

  1. Primary vs Latent TB
  2. Extra-pulmonary presentations of TB
  3. Ix?
  4. Mx?
  5. SEs of Mx?
A
  1. If infected with TB –> primary = symptomatic; latent = aymptomatic
  • Primary: caseating granulomas (‘cheese like’), fever, night sweats, weight loss, cough, haemoptysis
  • Latent: Gohn focus = granuloma with necrosed centre created via macrohphages and phagocytosis
  1. Extra-pulmonary Sx:
  • Lymphadenitis (most common), pericarditis, peritonitis, renal
  • Subacute meningitis: headaches, personality change, meningism
  • Spinal: Pott’s disease = back pain, discitis
  • Miliary TB: disseminated haematogenous spread (CXR = millet seeds)
  1. Ix:

ACTIVE TB:

  • CXR: R upper lobe cavitation
  • Sputum smear = Ziehl-Neelson (red)
  • Sputum culture = Lowenstein-Jensen medium for 6wks = GOLD STANDARD –> shows acid fast bacili

LATENT TB:

  • Tuberculin skin test (Mantoux) = shows exposure to TB (active/latent/BCG)
  • IGRA (Interferon-Gamma Release Assays): shows exposure (active/latent - NOT BCG)
  1. Management:

ACTIVE TB: 4 for 2, 2 for 4

  • RIPE: Rifampacin + Isoniazid (w/ pyridoxine) + Pyrazinamide + Ethambutol = all 4 for 2 months
  • Rifampacin + Isoniazid (w/ pyridoxine) = these 2 for further 4 months

NOTE: meningeal TB = RIPE for 12 months + steroids

LATENT TB:

  • Isoniazid (w/ pyridoxine) for 6 months
  • OR Rifampacin + Isoniazid (w/ pyridoxine) for 3 months

NOTE: prophylaxis = isoniazid 8-12 weeks (in children < 5 y/o)

  1. SEs of RIPE:

Rifampicin –> ‘pissing’ = orange secretions, hepatotoxicity
Isoniazid –> ‘I-so-NUMB-azid’ = peripheral neuropathy (that’s why given with B6), hepatotoxicity
Pyrazinamide –> hepatotoxicity, arthralgia, ↑ urea = gout
Ethambutol –> ‘Eye’ = optic neuritis

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4
Q

SUMMARY CARD:

Mycobacterium leprae (leprosy)
1. Sx?
2. Mx?

A

Paucibacillary (tuberculoid): limited skin disease (hypoprigmentation), asymmetric nerve involvement, hair loss

Multibacillary (lepromatous): extensive skin involvement (hypoprigmentation) + symmetrical nerve involvement

Mx: rifampicin, dapsone + clofazimine (triple therapy)

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5
Q

DISEASE:

What is the granuloma in latent TB called?

A

Gohn focus

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6
Q

DISEASE:

What is spinal TB called?

A

Pott’s disease

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7
Q

DISEASE:

What is seen on CXR for miliary TB?

A

Millet seeds

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8
Q

DISEASE:

What are the investigations for active TB?

imaging; smears; medium

A
  • CXR: R upper lobe cavitation
  • Sputum smear = Ziehl-Neelson (red)
  • Sputum culture = Lowenstein-Jensen medium for 6wks = GOLD STANDARD –> shows acid fast bacili
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9
Q

DISEASE:

What are the investigations for latent TB?

A
  • Tuberculin skin test (Mantoux) = shows exposure to TB (active/latent/BCG)
  • IGRA (Interferon-Gamma Release Assays): shows exposure (active/latent - NOT BCG)
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10
Q

DISEASE:

What is the Mx for active TB?

BONUS: what is the Mx for latent TB?

A
  • RIPE: Rifampacin + Isoniazid (w/ pyridoxine) + Pyrazinamide + Ethambutol = all 4 for 2 months
  • Rifampacin + Isoniazid (w/ pyridoxine) = these 2 for further 4 months

NOTE: meningeal TB = RIPE for 12 months + steroids

BONUS: LATENT TB:
* Isoniazid (w/ pyridoxine) for 6 months
* OR Rifampacin + Isoniazid (w/ pyridoxine) for 3 months

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11
Q

DISEASE:

Caseating granuloma, night sweats, haemoptysis, recently travelled to Asia

  1. What is the diagnosis?
  2. What are the SEs of the Mx?
A
  1. TB
  2. SEs:
  • Rifampicin –> ‘pissing’ = orange secretions, hepatotoxicity
  • Isoniazid –> ‘I-so-NUMB-azid’ = peripheral neuropathy (that’s why given with B6), hepatotoxicity
  • Pyrazinamide –> hepatotoxicity, arthralgia, ↑ urea = gout
  • Ethambutol –> ‘Eye’ = optic neuritis
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12
Q

DISEASE:

What is the BCG vaccine?

A

Bacille-Calmette-Guerin
Live-attentuated strain of M. bovis given to high-risk patients

CI = immunosuppressed patients (due to it being a live vaccine)

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13
Q

DISEASE:

Depigmentation of skin + nerve thickening & peripheral neuropathy; ZN stain shows AFB

What is the causative organism?

A

Mycobacterium leprae –> causes leprosy

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14
Q

DISEASE:

Disseminated infection in immunocompromised
Slow-growing
ZN stain shows AFB

What is the causative organism?

A

Mycobacterium avium complex

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15
Q

DISEASE:

PMHx = CF, rapid-growing, ZN stain shows AFB

What is the causative organism?
BONUS: Mx?

A

Mycobacterium abscessus

Mx = macrolide e.g. clarithromycin

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16
Q

DISEASE:

Australia / tropics, painless nodules progressing to ulceration, scarring, contractures

What is the causative organism?

BONUS: name of ulcers

A

Mycobacterium ulcerans

BONUS: Buruli ulcer

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17
Q

DISEASE:

Aquarium owner, subcutaneous nodules

What is the causative organism?

A

Mycobacterium marinum

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18
Q

SUMMARY CARD:

What are the different ways of classifying pneumonia?

A

1. CAP vs HAP:

  • HAP = >48hrs after hospital admission
  • Common HAP = S. aureus, Klebsiella, Pseudomonas, Haemophilus

2. Typical vs Atypical:

  • Typical = classic rapid development of signs and symptoms, classic CXR changes (e.g. consolidation), responsive to penicillin Abx
  • Atypical = no / atypical signs e.g. dry cough, does not respond to penicillin Abx (because no cell wall), more responsive to macrolides e.g. clarithromycin; extra-pulmonary Sx e.g. rashes, hepatitis, hyponatraemia
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19
Q

SUMMARY CARD:

Typical pneumonia organisms:

A
  1. Strep. pneumoniae: most common, rusty-coloured sputum; CXR = lobar; microscopy = +ve diplococci
  2. Haemophilus influenzae: associated w/ pre-existing lung disease (e.g. COPD, bronchiectasis); CXR = bronchoalveolar pattern (lower lobes), “glossy colonies”; microscopy = -ve cocco-bacilli
  3. Moraxella catarrhalis: associated w/ smoking and underlying lung disease; microscopy = -ve cocci
  4. Staphylococcus aureus: recent viral infection, CXR = cavitatation; microscopy = +ve cocci “grape bunch clusters” & coagulase +ve
  5. Klebsiella pneumoniae: alcoholics & diabetics, haemoptysis (red-currant jelly sputum), CXR = upper lobe cavitation; microscopy = -ve bacilli
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20
Q

SUMMARY CARD:

Atypical pneumonia organisms (including fungal):

Clues: legionella, mycoplasma, chlamydia, Q fever, pertussis, TB, burkholderia, pseudomonas, aspergillus, PCP

A
  1. Legionella pneumophilia: water /air conditioning, confusion, hepatitis, hyponatreaemia, urinary antigen +ve; charcoal yeast
  2. Mycoplasma pneumoniae: uni students / boarding schools, dry cough, arthralgia, cold agglutination, erythema multiforme and target shaped lesions on palm; Mx: macrolide
  3. Chlamydia pneumoniae: children and adolescents
  4. Chlamydia psittaci: birds, haemolytic anaemia, splenomegaly, rose spots
  5. Coxiella burnetii: AKA Q fever, exposure to farm animals; microscopy = -ve coccobacilli
  6. Bordetella pertussis: AKA whooping cough, unvaccinated (immigrant); microscopy = -ve coccobacilli
  7. Mycobacterium tuberculosis: prolonged flu-like prodrome w/ TB symptoms; CXR = upper lobe cavitation or “millet seed” (miliary TB); microscopy = +ve bacilli
  8. Burkholderia cepecia: associated w/ CF, persistent infection and poor prognosis; microscopy = -ve bacilli
  9. Pseudomonas aeruginosa: CF; Mx: Tazocin OR ciprofloxacin +/- gentamicin; microscopy = -ve coccobacilli
  10. Aspergillus fumigatus (fungi): fungal ball in pre-existing (usually TB) cavity, CXR = Halo sign, neutropenia
  11. Pneumocystis jiroveci (fungi): associated with HIV, CXR = Bat’s wing, HRCT = bilateral ground-glass shadowing; silver stain +ve = cysts; histology = boat shapes; Mx: co-trimoxazole
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21
Q

SUMMARY CARD:

Which organisms do the following immunosuppressions predispose you to:
1. HIV
2. Splenectomy
3. CF
4. Neutropenia

A
  1. HIV: pneumocystitis jiroveci, TB
  2. Splenectomy: NHS = neisseria meningitidis, haemophilus influenzae, strep. pneumoniae
  3. CF: pseudomonas aeruginosa, burkholderia cepacia
  4. Neutropenia: aspergillus
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22
Q

DISEASE:

Mx for pneumoniae:
1. What scoring system is used?
2. Typical (+ legionella + staph)
3. Atypical: PCP, pseudomonas, MRSA
4. HAP (+severe HAP)
3. Aspiration
4. Anaerobic

A

CURB-65 –> 1 point for confusion, urea >7, RR>30, BP < 90/60, > 64 y/o

  • CURB-65 0-1 (mild): outpatient –> amoxicillin PO 5 days; if pen allergy then macrolide PO 5 days
  • CURB-65 2 (mod): consider admission –> amoxicillin PO 5-7 days + clarithyromyin PO 5-7 days
  • CURB-65 3-5 (severe): admit +/- consider ITU –> co-amoxiclav IV 7 days + clarithromycin IV 7 days
  • Legionella: Clarithromycin + Rifampicin
  • Staphylococcus: Flucloxacillin

ATYPICALS:

  • PCP (pneumocystitis jiroveci): co-trimoxazole
  • Pseudomonas: tazocin OR ciprofloxacin +/- gentamicin
  • MRSA: vancomycin

HAP: ciprofloxacin + vancomycin
Severe HAP: tazocin + vancomycin

ASPIRATION: tazocin + metronidazole

ANAEROBIC bacteria: clindamycin +/- metronidazole

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23
Q

DISEASE:

rusty-coloured sputum
CXR = lobar consolidation
microscopy = +ve diplococci
Had a SPLENECTOMY

no confusion, urea < 7, RR < 30, BP > 90/60, age > 65

  1. Causative organism?
  2. Mx?
A

Strep pneumoniae (typical)
CURB-65 is 1 = mild –> amoxicillin PO 5 days

Note: splenectomy predisposes to NHS organisms (Neisseria meningitides, haemophilus influenzae, streptococcus pneumoniae)

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24
Q

DISEASE:

PMHx = COPD
cough, haemoptysis
CXR = bronchoalveolar ‘glossy colonies’ in the lower lobes

  1. Causative organism?
  2. Microscopy?
A
  1. Haemophilus influenzae (typical)
  2. -ve coccibacilli
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25
Q

DISEASE:

recent URTI
CXR = cavity
microscopy = +ve cocci clusters

  1. Causative organism?
  2. BONUS: which protein enzyme +ve?
  3. Mx?
A
  1. Staph aureus (typical)
  2. coagulase +ve
  3. Flucloxacillin
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26
Q

DISEASE:

Diabetic + alcoholic
redcurrant jelly sputum
CXR = upper lobe cavity

  1. Causative organism?
  2. microscopy?
A
  1. Klebsiella pneumoniae (typical)
  2. -ve bacilli
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27
Q

DISEASE:

recent trip from abroad, stayed in air conditioned hotel
confused
hyponatraemia
hepatitis

  1. Causative organism?
  2. Mx?
A
  1. legionella pneumophilia
  2. Clarithromycin + rifampicin
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28
Q

DISEASE:

Uni student, lives in halls with many other students
dry cough, arthralgia
cold agglutins
ethythema multiforme (target shaped rash on palms)
No culture (with sputum or CSF) and nothing shows up on gram stain

  1. Causative organism
  2. Mx?
A
  1. Mycoplasma pneumoniae
  2. Macrolide e.g. clarithromycin
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29
Q

DISEASE:

Works with birds
haemolytic anaemia
splenomegaly
rose spots

  1. Causative organism?
A
  1. Chlamydia psittaci
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30
Q

DISEASE:

Exposure to farm animals
Histology: -ve coccobacilli

  1. Causative organism (+ diagnosis)?

hint: 1 letter

A

Coxiella burnetii (AKA Q fever)

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31
Q

DISEASE:

Unvaccinated immigrant
Paroxysmal coughing w/ inspiratory whoop

  1. Causative organism (+ diagnosis)?
  2. Mx?
A

Bordetella pertussis (AKA whooping cough)

Mx = Abx if cough < 21 days of onset –> macrolides:
< 1 month old = clarithromycin
>1 month old = azithromycin
(if macrolides CI, consider co-amoxiclav)
Return to school 2 days after commencing abx Tx OR 21 days after cough onset

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32
Q

DISEASE:

prolonged flu-like prodrome
haemoptysis
CXR = cavitation in upper lobe
HIV +ve

  1. Causative organism (+ diagnosis)
  2. What is seen on microscopy?
A
  1. Mycoplasma tuberculosis (AKA TB)
  2. gram +ve bacilli
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33
Q

DISEASE:

PMHx: CF
Persistent infection + poor prognosis
histology: gram -ve rod

  1. Causative organism?
A
  1. Burkholderia cepecia
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34
Q

DISEASE:

PMHx: CF
histology: gram -ve coccobacilli

  1. Causative organism?
  2. Mx?

moan

A

Pseudomonas aeruginosa

Mx = Tazocin OR ciprofloxacin +/- gentamicin

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35
Q

DISEASE:

Neutropenia
CXR = halo sign

  1. Causative organism?

(FUN GUY)

A

aspergillus fumigatus

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36
Q

DISEASE:

PMHx: HIV
CXR = Bat’s wing
HRCT = bilateral ground-glass shadowing
Microscopy = ‘boat-shapes’

  1. Causative organism?
  2. What type of staining is +ve?
  3. Mx?
A
  1. Pneumocystitis jiroveci
  2. silver stain +ve
  3. co-trimoxazole
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37
Q

DISEASE:

Pt develops pneumonia 8 days after being admitted to the hospital wards

  1. Mx?
  2. BONUS: Mx for severe HAP
A

HAP = develop pneumonia >2 days after being admitted to hospital

Mx = ciprofloxacin + vancomycin
Severe HAP Mx = tazocin + vancomycin

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38
Q

DISEASE:

Elderly patient with altered mental status, fever, and cough, diagnosed with aspiration pneumonia

  1. Mx?
A

tazocin + metronidazole

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39
Q

DISEASE:

Anaerobic bacteria causing pneumonia

  1. Mx?
A

clindamycin +/- metronidazole

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40
Q

SUMMARY CARD:

How to differentiate between:
1. Bronchitis
2. Pneumonia
3. Lung abscess
4. Emphysema

symptomatically

A
  1. Bronchitis: affects normal sized vessels, normal CXR
  2. Pneumonia: unwell pt + affects lung parenchyma
  3. Abscess: swinging fevers + cavity in lung parenchyma, FLAWS, unresponsive to abx + requires drainage
  4. Emphysema = infected pleural effusion
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41
Q

SUMMARY CARD:

  1. What is infective endocarditis?
  2. Which valves are most commonly affected?
  3. S&S?
  4. Ix?

Hint: Duke criteria

A
  1. bacteria form vegetations on valve(s)
  2. Usually affects the valves on the L side = mitral and aortic –> this is due to increased pressure on L side of heart which causes damage to those valves making it more susceptible to bacterial growth

NOTE: R sided (tricuspid) is most common in IVDU (as circulation returns to R side of heart first)

  1. S&S: ACUTE = fever (pyrexia of unknown origin (PUO)); new heart murmur that changes day to day (usually regurgitant), non specific Sx (anorexia, weight loss, malaise, fatigue etc.); HF, rapidly septic

NOTE: in subacute infective endocarditis (develops over weeks-months) –> new heart murmur + FLAWS + embolic phenomena (e.g. janeway lesions, splinter haemorrhages, splenomegaly) & immune phenomena (e.g. roth spots in eyes, osler's nodes in hands, haematuria due to glomerulonephritis)

  1. Ix: Blood cultures = ideally from 3 different sites before starting abx; echocardiogram; DUKE'S CRITERIA: need 2 major OR 1 major + 3 minor OR 5 minor
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42
Q

SUMMARY CARD:

What are Duke’s criteria?

A

Major:

  • Positive blood culture growing typical organisms (>2x cultures >12 hrs apart)
  • New regurgitant murmur OR evidence of vegetation on echo

Minor:

  • RFs: long-term lines (e.g. in ITU), IVDU, poor dentician, prosthetic valve, rheumatic heart disease, immunosuppression
  • Fever >38°C
  • Embolic phenomena (e.g. janeway lesions, splinter haemorrhages, splenomegaly)
  • Immune phenomena (e.g. roth spots in eyes, osler's nodes in hands, haematuria due to glomerulonephritis)
  • Positive blood culture not meeting the major criteria

For infective endocarditis diagnosis: need 2 major OR 1 major + 3 minor OR 5 minor

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43
Q

SUMMARY CARD:

Infective endocarditis Mx?

A

IV abx for 6 weeks
Start empirically as soon as cultures taken, then change according to sensitivities

Rule of thumbs:
ACUTE: flucloxacillin (cause staph aureus most common)
SUBACUTE: benzylpenicillin + gentamicin
Prosthetic valve: vancomycin + gentamicin + rifampicin

Consider surgical debridement

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44
Q

SUMMARY CARD:

What are the different pathogens that can cause infective endocarditis?

A
  1. ACUTE (high virulence bacteria = rapid onset of symptoms):
  • Streptococcus pyrogenes (Group A strep) = rheumatic fever
  • Staph aureus (most common in IVDU)
  • Coagulase-negative staphylococci (most common in prosthetic valve)
  1. SUBACUTE (low virulence bacteria = slower onset of symptoms):
  • Staphylococcus epidermidis (most common post-valvular surgery)
  • Streptococcus viridans (more common in low resource countries, dental work)
  • HACEK = do not grow on culture –> haemophilus, acinetobacter, cardiobacterium, eikinella, kingella
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45
Q

DISEASE:

PUO for last 8 weeks (>38°C)
Osler’s nodes on hands
New regurgitation murmur
post valvular surgery with prosthetic valve

  1. causative organism
  2. Mx?
A
  1. staphylococcus epidermidis (coagulase negative staphylococcus)
  2. Mx = IV vancomycin + gentamicin + rifampicin

BONUS: fulfils 1 major and 3 minor of Duke’s criteria

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46
Q

DISEASE:

fever for past 4 days, now septic
IVDU
Blood culture grows gram positive diplococci in clusters

  1. causative organism (+diagnosis)
  2. Mx?
A
  1. staph aureus (infective endocarditis)
  2. IV flucloxacillin
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47
Q

DISEASE:

Young patient with recent pharyngitis, fever, and new-onset murmur

  1. causative organism (+diagnosis)?
A
  1. Strep pyogenes AKA group A strep (AKA rheumatic fever)
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48
Q

DISEASE:

Middle-aged patient with dental procedure history, fever, and new-onset murmur

  1. causative organism (+ diagnosis)?
A
  1. streptococcus viridans (causing infective endocarditis)
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49
Q

SUMMARY CARD:

What are the different types of diarrhoea caused by GI infections?

BONUS: which organisms cause which?

A
  1. Secretory diarrhoea: watery diarrhoea, no fever
  • Toxin production causes Cl- to be secreted into the lumen which leads to diarrhoea = loss of water + electrolytes
  • Organisms: vibrio cholerae (rice water stool), enterotoxigenic Escherichia Coli (ETEC; traveller's diarrhoea), Enteropathogenic Escherichia coli (EPEC), bacillus cereus (reheated rice), staph aureus (short incubation period)
  1. Inflammatory diarrhoea: BLOODY diarrhoea w/ mucus (AKA dysentery), fever
  • Inflammation + bacteraemia
  • Organisms: CHESS
  • Campylobacter jejuni (complication = GBS), haemorrhagic E. coli, Entamoeba histolytica, Shigella, Salmonella
  1. Enteric fever: unwell with fever, GI symptoms
  • Organisms: salmonella typhi (typhoid fever), yersinia enterocolitica, brucella
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50
Q

SUMMARY CARD:

What are the gram +ve organisms that cause GI infections / diarrhoea?

3 types of clostridium, bacillus, staph, listeria

A
  1. Clostridium botulinum: toxin blocks Ach release from peripheral nerves = DESCENDING paralysis; toxin can be inactivated by cooking; from canned / vacuum packed foods (honey = kids, beans = students); Mx = antitoxin
  2. Clostridium perfringens: from reheated meats; 8-16hr incubation and lasts ~24hrs; watery diarrhoea + cramps; causes gas gangrene (alpha toxin in infected tissue necroses + releases foul smelling gas)
  3. Clostridium difficile: causes pseudomembranous colitis (looks like wet cornflakes on colonscopy); caused by the 4 C’s (cephalosporins, clindamycin, ciprofloxacilin, co-amoxiclav); Mx = IV metronidazole or oral vancomycin
  4. Bacillus cereus: cereulide toxin; reheated fried rice; watery non-bloody diarrhoea + vomiting within 4hrs; self-limiting
  5. Staphylococcus aureus: S. aureus enterotoxin = vomiting + watery non-bloody diarrhoea with SHORT incubation period (< 2hrs); self-limiting
  6. Listeria monocytogenes: microscopy shows tumbling motility; refrigerated food e.g. CHEESE (unpasteurised dairy); perinatal infection; severe infection in immunocompromised; Mx = ampicillin

NOTE: ALL are gram +ve bacilli except staph aureus (which is gram +ve diplococci in clusters)

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51
Q

SUMMARY CARD:

What are the gram -ve organisms that cause GI infections / diarrhoea?

4 E. coli, 2 Salmonella, 3 vibrio, campylobacter, shigella, Yersinia,

A
  1. (enterotoxigenic) Escherichia coli (ETEC): toxigen, traveller’s diarrhoea
  2. (enteropathogenic) Escherichia coli (EPEC): pathogenic, paediatric/infantile diarrhoea
  3. (enteroinvasive) Escherichia coli (EIEC): invasive; bloody diarrhoea w/cramps + N/V
  4. (enterohaemorrhagic) Escherichia coli (EHEC): haemorrhagic –> haemolytic uraemic syndrome (HUS) = triad of thrombocytopenia, MAHA (anaemia) and AKI; caused by Shiga toxin-producing E.coli (STEC) 0157:H7
  5. Salmonella typhi/ paratyphi: typhoid (/ paratyphoid) fever; faecal-oral route; rose spots, constipation > diarrhoea, multiplies in Peyer’s patches; Mx = IV ceftriaxone then PO azithromycin; complication = osteomyelitis in SCA
  6. Salmonella enteritides: contaminated poultry, eggs (BBQ); non-bloody diarrhoea, abdominal pain that comes and goes in waves; self-limiting (or ceftriaxone if required)

NOTE: vibrio = comma-shaped bacteria

  1. Vibrio cholera: comma-shaped bacteria; enterotoxin A + B; rice water stool, severe dehydration that leads to weight loss; Mx: self-limiting (or doxycycline if required)
  2. Vibrio parahaemolyticus: comma-shaped bacteria; cruise ships / Japan = undercooked / raw seafood; ~3 days of diarrhoea; Mx: doxycycline
  3. Vibrio vulnificus: comma-shaped bacteria; ; causes cellulitis in shellfish handlers; if PMH of HIV = can cause sepsis, D+V; Mx: doxycycline
  4. Campylobacter jejuni: also comma-shaped bacteria gram -ve, oxidase +ve; unpasteurised milk and poultry (mainly chicken); prodrome of headache and fever; watery diarrhoea that turns bloody; complication = Guillain-Barre syndrome; Mx = if in first 5 days, erythromycin or ciprofloxacin
  5. Shigella: Shiga toxin (inactivates 60S ribosome) ; bloody diarrhoea w/pain; Mx = if not self-limiting then ciprofloxacin
  6. Yersinia enterocolitica: faecal-oral route, Peyer’s patches, enterocolitis; complication = reactive arthritis

NOTE: ALL gram -ve bacilli

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52
Q

SUMMARY CARD:

What are the protozoa that cause GI infections / diarrhoea?

A
  1. Entamoeba histolytica: dysentery –> mobile trophozoite w/ 4 nuclei, main RF = MSM; if trophozoites enter portal vein it causes liver cyst/abscess (anchovy paste appearance); flask-shaped ulcer; Mx = metronidazole + paromomycin
  2. Giardia lamblia: pear-shaped trophozoite w/ 2 nuclei; prolonged smelly, explosive non-bloody diarrhoea; biopsy = partial villous atrophy; Mx = Metronidazole
  3. Cryptosporidium parvum: severe diarrhoea in immunocompromised; Kinyoun acid-fast stain w/oocytes in stool; Mx = Paromomycin
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53
Q

SUMMARY CARD:

What are the viruses that can cause GI infection / diarrhoea?

A
  1. Rotavirus: most common cause in children; w/ fever + vomiting, watery diarrhoea
  2. Norovirus: G2.4 predominant strain; lots of vomiting; can cause outbreaks in adults
  3. Adenovirus: infants (often immunocompromised); non-bloody diarrhoea
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54
Q

DISEASE:

Which is the most common cause of viral gastroenteritis in children?

schedule

A

Rotavirus

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55
Q

DISEASE:

45F - severe vomiting after family gathering
sudden onset nausea + watery diarrhoea

which cause of viral gastroenteritis is this?

A

norovirus

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56
Q

DISEASE:

Uni student
Had canned beans for mexican food night
descending paralysis (+ dysphagia + blurred vision)
microscopy: gram +ve bacilli

  1. causative organism?
  2. BONUS: Mx?
A

Clostridium botulinum –> botulism toxin
Mx = antitoxin

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57
Q

DISEASE:

reheated leftover sunday roast
watery diarrhoea and cramps for the past 10 hrs
complains of passing gas that is very foul smelling
microscopy: gram +ve bacilli

  1. causative organism?
  2. BONUS: what are the RFs?
A
  1. clostridium perfringens
  2. RFs = reheated meat; incubation period of 8-16hrs, Sx lasts 24hrs

NOTE: foul smelling gas suggestive of gas gangrene

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58
Q

DISEASE:

Severe diarrhoea
colonoscopy shows ‘wet cornflakes appearance’
recently finished a course of abx
microscopy: gram +ve bacilli

  1. causative organism?
  2. 4 C’s that can lead to overgrowth of this bacterium
  3. Mx?
A
  1. clostridium difficile –> causes pseudomembranous colitis (looks like wet cornflakes on colonscopy)

NOTE: other complications include toxic megacolon

  1. 4 C’s = cephalosporins, clindamycin, ciprofloxacilin, co-amoxiclav
  2. IV metronidazole or oral vancomycin
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59
Q

DISEASE:

Pt reheated leftover chinese takeaway
4hrs later, sudden vomiting + non-bloody diarrhoea
microscopy: gram +ve bacilli

  1. causative organism?
A

bacillus cereus –> self-limiting
RF = reheated rice, incubation period ~4hrs

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60
Q

DISEASE:

Pt went out for a meal and developed vomiting and water diarrhoea in < 2 hours

  1. causative organism?
  2. microscopy?
A
  1. staphylococcus aureus –> short incubation period + self-limiting
  2. gram +ve diplococci in clusters
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61
Q

DISEASE:

unpasteurised cheese in pregnancy
D&V
microscopy: gram +ve bacilli w/ tumbling motility

  1. causative organism?
  2. Mx?
A

listeria monocytogenes
Mx = ampicillin, ceftriaxone, co-trimoxazole

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62
Q

DISEASE:

traveller’s diarrhoea
e.g. watery diarrhea, abdominal cramps, and low-grade fever after consuming street food in SE asia

  1. causative organism?
A

ETEC (enterotoxigenic E. coli) –> gram -ve bacilli

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63
Q

DISEASE:

2 y/o child has severe watery diarrhoea and vomiting after attending daycare
microscopy: gram -ve bacilli

  1. causative organism?

type of E coli

A

EPEC (enteropathogenic E. coli) = paeds

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64
Q

DISEASE:

6 y/o w/ bloody diarrhoea, abdominal pain and decreased urine output
Lab tests show haemolytic anaemia + thrombocytopenia + AKI

  1. causative organism (+diagnosis)
A

haemolytic uraemic syndrome (HUS) –> caused by EHEC 0157:H7 (enterohemorrhagic Escherichia coli) which releases Shiga toxin

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65
Q

DISEASE:

constipation > diarrhoea
rose spots
splenomegaly

  1. causative organism (+ diagnosis)?
  2. complications?
  3. Mx?

causes osteomyelitis in SCA pts

A
  1. salmonella typhi (AKA typhoid fever)
  2. osteomyelitis in SCA pts
  3. IV ceftriaxone then PO azithromycin
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66
Q

DISEASE:

Recent BBQ (contaminated poultry)
fever, vomiting, malaise, followed by diarrhoea
abdominal pain that comes and goes in waves

  1. causative organism?
  2. Mx?
A
  1. Salmonella enterides
  2. self-limited, resolves in ~3 days (or ceftriaxone if required)
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67
Q

DISEASE:

comma-shaped bacteria
rice water stool + weight loss (due to dehydration)

  1. causative organism?
  2. toxins?
  3. Mx?
A
  1. Vibrio cholera
  2. enterotoxins A + B
  3. self-limiting (if not doxycycline)

NOTE: all vibrios are comma shaped

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68
Q

DISEASE:

cruise ships / Japan = undercooked / raw seafood
~3 days of diarrhoea

  1. causative organism?
  2. Mx?
A
  1. vibrio parahaemolyticus
  2. doxycycline
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69
Q

DISEASE:

Initially presented with cellulitis
As HIV +ve, quickly progressed to sepsis
Works as a shellfish handlers

  1. causative organism?
  2. Mx?
A
  1. Vibrio vulnificus
  2. Doxycycline
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70
Q

DISEASE:

Unpasteurised meat / milk products (esp. chickens)
bloody diarrhoea, foul smelling
bloating + cramps
microscopy: S / comma shaped, gram -ve, oxidase +ve

  1. causative organism?
  2. complication?
  3. Mx?
A
  1. Campylobacter jejuni
  2. complication = Guillain-Barre syndrome
  3. Mx = if in first 5 days, erythromycin or ciprofloxacin
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71
Q

DISEASE:

abdominal pain and watery diarrhoea after consuming undercooked pork
Peyer’s patches in terminal ileum
Complications = reactive arthritis

  1. causative organism?
A

Yersinia enterocolitica

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72
Q

DISEASE:

dysentry, flatulence, tenesmus
MSM
microscopy = mobile trophozoite w/ 4 nuclei,
liver cyst/abscess (anchovy paste appearance on USS)
flask-shaped ulcer

  1. causative organism?
  2. Mx?
A
  1. Entamoeba histolytica (protozoa)
  2. Mx = metronidazole + paromomycin
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73
Q

DISEASE:

pear-shaped trophozoite w/ 2 nuclei
flatulence, prolonged smelly, explosive non-bloody diarrhoea
RFs: travellers, MSM, campers, hikers
biopsy = partial villous atrophy

  1. causative organism?
  2. Mx?
A
  1. giardia lamblia (protozoa)
  2. Mx = oral Metronidazole
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74
Q

DISEASE:

severe diarrhoea in immunocompromised
oocytes seen in stool w/ Kinyoun acid-fast stain

  1. causative organism?
  2. Mx?
A
  1. Cryptosporidium parvum (protozoa)
  2. Mx = Paromomycin
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75
Q

SUMMARY CARD:

What are the different ways to classify UTIs?

Ix?

complicated vs uncomplicated; lower vs upper

A

Uncomplicated = women
Complicated = men, catheters, pregnancy, functionally / structurally abnormal tract

Lower = affects only the bladder
Upper = affects kidneys, systemically unwell

  • Urinalysis (not typically done in men, women > 65 y/o or catheterised): shows ↑ nitrites (specific for UTI) and ↑ leukocytes (founnd in any inflammatory condition of the urinary tract)
  • Urine culture: >10^4 colony forming units / ml = diagnostic (note: mixed growth or squamous cells suggests contaminated sample)

NOTE: >10^3 colony forming units / ml is used for E. coli and S. saprophyticus

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76
Q

SUMMARY CARD:

What is the management of UTIs?
1. Uncomplicated?
2. Complicated?
3. Pyelonephritis?
4. Pregnancy?
5. Catheter-associated?

BONUS: what is trimethoprim CI against?

A
  1. Uncomplicated: nitrofurantoin (or trimethoprim) for 3 days
  2. Complicated (e.g. male or previous Hx w/resistant organisms): nitrofurantoin (or trimethoprim / cefalexin) for 7 days
  3. Pyelonephritis: admit + IV co-amoxiclav / amikacin / cefalexin
  4. Pregnancy: nitrofurantoin (but congenital malformations at 3rd trimester), at term = co-amoxiclav/cefalexin/trimethoprim

NOTE: nitrofurantoin can increase the risk of haemolytic anaemia in newborn if administered close to term; and trimethoprim (folate antagonist) can cause neural tube defects if administered in the first trimester

  1. Catheter-associated: remove catheter + aminoglycoside (e.g. gentamicin) OR if candida, then no antifungal unless awaiting renal transplant (then oral fluconazole)

BONUS: trimethoprim is a folate antagonist, therefore it is NOT prescribed if pt is on methotrexate!

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77
Q

SUMMARY CARD:

What are the different organisms that can cause UTIs and their features?

Hint: 3 gram +ve, 4 gram -ve, 1 fungus

3 staph, E.coli, klebsiella, enterobacter, proteus mirabilis, candida

A
  1. Escherichia coli (most common) = lactose fermenting gram -ve bacilli; classically young women who are sexually active);
  2. Staphylococcus saprophyticus = gram +ve cocci in clusters; 2nd most common in young women; catalase +ve, coagulase -ve; associated with catheters; has p-fimbriae (a protein) that allows adherence to the urinary tract
  3. Staphylococcus aureus = gram +ve cocci in clusters; catalase +ve, coagulase +ve; most common cause of haematogenous spread so take blood cultures as likely to have bacteraemia
  4. Staphylococcus epidermidis = gram +ve cocci; indwelling catheter; catalase +ve, coagulase -ve
  5. Proteus mirabilis = gram -ve bacilli; associated with kidney stones –> struvite stones (staghorn calculi), young boys

NOTE: this is because proteus mirabilis produce urease, which converts ammonia to urea, which leads to alkaline urine pH and struvite crystals

  1. Klebsiella = lactose fermenting gram -ve bacilli; associated w/ immunocompromised + indwelling catheter
  2. Enterobacter = lactose fermenting gram -ve bacilli; associated w/ immunocompromised
  3. Candida albicans = fungus; catheter-associated
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78
Q

DISEASE:

Which 3 UTI organisms are lactose fermenting?

A
  1. E. coli
  2. Klebsiella
  3. Enterobacter
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79
Q

DISEASE:

sexually active young woman w/ dysuria + frequency
urine dip: haematuria ++, nitrites ++

  1. causative organism?
  2. microscopy?
A
  1. E. coli
  2. gram -ve bacilli (lactose fermenting)
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80
Q

DISEASE:

young women w/ dysuria + frequency
urine dip: haematuria ++, nitrites ++
microscopy: gram +ve cocci

  1. causative organism?
  2. BONUS: coagulase & catalase?
  3. Mx?
A

Staphylococcus saprophyticus
catalase +ve, coagulase -ve
Mx = 3 days nitrofurantoin

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81
Q

DISEASE:

young boy
suprapubic tenderness, dysuria, foul smelling urine
alkaline urine pH

  1. causative organism?
  2. complication?
A
  1. proteus mirabilis (-ve bacilli)
  2. proteus mirabilis produces urease –> converts ammonia to urea, which leads to alkaline urine pH and struvite crystals (kidney stones - AKA staghorn calculi)
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82
Q

DISEASE:

Elderly pt w/ long-standing catheter
signs of confusion / delirium
microscopy: budding yeast cells

  1. causative organism?
  2. Mx?
A
  1. candida albicans
  2. remove catheter, no Mx unless pt awaiting renal transplant (then oral fluconazole)
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83
Q

DISEASE:

immunocompromised pt w/ catheter
suprapubic tenderness, cloudy urine
microscopy = lactose fermenting gram -ve bacilli

  1. causative organism?
A

Klebsiella

NOTE: enterobacter also lactose fermenting gram -ve bacilli found in immunocompromised pts (not associated with catheters though)

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84
Q

DISEASE:

30 y/o man with suprapubic tenderness, haematuria + dysuria
blood cultures: bacteraemia
microscopy: gram +ve cocci, catalase +ve, coagulase +ve

  1. causative organism?
  2. Mx?
A
  1. Staph aureus
  2. 7 days nitrofurantoin (because men = complicated = longer abx duration)
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85
Q

DISEASE:

State the most likely causative organisms, RFs and Mx of the following wound / bone / joint infections:

  1. Septic arthritis
  2. Osteomyelitis
  3. Prosthetic joint infection
  4. Surgical site infection
A
  1. Septic arthritis: neisseria gonorrhoea in young pts; staphylococcus aureus> strep > E. coli in older pts
  • RFs: pre-existing arthritis, diabetes, CKD, liver failure
  • S&S: pyrexia, swollen joint (knee most likely affected), red, hot and reduced movement
  • Ix: joint aspirate
  • Mx: drain joint + IV cefotaxime for N. gon; IV fluclox for staph
  1. Osteomyelitis: staphylococcus aureus, or salmonella if SCA, or pseudomonas if IVDU
  • S&S: lumbar most affected region = vertebral pain,
  • Mx = IV fluclox for staph aureus, IV piperacillin for pseudomonas cover
  • Radical debridement if chronic osteomyelitis
  1. Prosthetic joint infection: CoNS (coagulase-negative staphylococci) e.g. staph epidermis
  • Signs same as septic arthritis
  • Radiology would show loosening of the bone
  • Mx: remove prosthesis + IV vancomycin and oral rifampicin
  1. Surgical site infection: staph aureus > E. col > strep
  • 2nd most common HAI
  • Mx = oral/IV flucloxacillin OR if (suspected) MRSA = IV vancomycin/linezolid
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86
Q

DISEASE:

28 y/o sexually active man
severe pain and swelling in L knee joint + low-grade fever
Joint aspiration = purulent fluid

  1. diagnosis + causative organism?
  2. Mx?
A

Septic arthritis –> due to Neisseria gonorrhoea (gram -ve diplococci)
Mx = drain joint + IV cefotaxime

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87
Q

DISEASE:

50 y/o man w/ poorly controlled diabetes
Chronic lower back pain + difficulty walking for past month
Tenderness over the lumbar spine + limited ROM. X-ray = periosteal thickening + bone destruction

  1. diagnosis + causative organism?
  2. Mx?
A
  1. osteomyelitis (lumbar region most commonly affected) –> staph aureus = most common causative organism
  2. Mx = IV flucloxacillin; chronic osteomyelitis = surgical debridement
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88
Q

DISEASE:

  1. osteomyelitis in SCA –> causative organism?
  2. osteomyelitis in IVDU –> causative organism?
A
  1. salmonella typhi
  2. pseudomonas aureginosa
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89
Q

DISEASE:

65F w/ PMHx of RA has worsening pain + swelling of R hip joint, where she had a total hip replacement 6 months ago
Imaging = loosening of the prosthetic components

  1. diagnosis + causative organism?
  2. Mx?
A
  1. prosthetic joint infection –> staphylococcus epidermis (or other CoNS = coagulase neg staph)
  2. remove prosthesis + IV vancomycin and oral rifampicin
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90
Q

DISEASE:

45M - underwent elective abdo surgery for hernia repair
2 days post-op, develops increasing redness, warmth, and purulent discharge at the surgical incision site

  1. diagnosis + causative organism?
  2. Mx?
A
  1. surgical site infection –> staph aureus
  2. IV flucloxacillin
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91
Q

SUMMARY CARD:

What is the difference between meningitis & encephalitis?

definition, S&S

A

Meningitis = inflammation of meninges

  • S&S = meningism e.g. stiff neck, photophobia, headache
  • Ix = LP > abx; gram stain for bacteria, PCR for virus, India ink stain for cryptococcus, ZN stain for TB

VS

Encephalitis = inflammation of the brain parenchyma

  • S&S = meningism + altered mental status e.g. confusion, fluctuating consiousness
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92
Q

SUMMARY CARD:

Causative organisms for meningitis?

bacterial, viral, fungal, TB

A

1. Bacterial: CSF = very high neutrophils, high protein, low glucose

  • Neisseria meningitidis (gram -ve), streptococcus pneumoniae (gram +ve)
  • Ix = gram stain
  • Neonates: GBS, listeria monocytogenes, E. coli
  • Elderly: GBS, listeria monocytogenes
  • RFs for N. meningitidis = complement deficiency, hyposplenism (NHS), hypogammaglobulinaemia
  • RFs for strep. pneumoniae = complement deficiency, hyposplenism (NHS), immunosuppressed (alcoholic), infection (pneumonia), previous head trauma w/ CSF leak
  • Mx = IV ceftriaxone + corticosteroids (+ listeria cover for neonates / elderly w/ ampicillin)

2. Viral: CSF = very high lymphocytes, high protein, normal glucose

  • Enteroviruses e.g. coxsackie, echovirus
  • Mumps
  • HSV2
  • Ix = PCR

3. Fungal:

  • Cryptococcus neoformans (chronic) –> India ink stain

4. TB: CSF = high lymphocytes, VERY HIGH protein, low glucose

  • CHRONIC meningitis
  • Ix = Ziehl-Neelson stain
  • Mx: Dexamethasone w/anti-TB drugs
  • MRI: leptomeningeal enhancement
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93
Q

SUMMARY CARD:

Causative organism for encephalitis?

BONUS: Ix + Mx?

A

Most commonly caused by HSV 1
Ix = temporal + inferior frontal lobes affected
Mx = IV aciclovir

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94
Q

SUMMARY CARD:

Causative organisms and S&S of the following CNS infections:
1. myelitis
2. tetanus
3. brain abscess

HINT: 1. paralysis; 2. tetanospasmin; 3. TRIAD

A
  1. Myelitis: poliovirus; Sx = paralysis w/ preceding muscle fasciculations
  2. Tetanus: clostridium tetani; RFs = IVDU; tetanospasmin prevents GABA + glycine release, which leads to rigid spastic paralysis, lockjaw (trismus), opisthotonos (arched back); Mx = metronidazole
  3. Brain abscess: staph / strep; TRIAD: headache (dull, persistent), swinging fever + focal neurology (due to space occupying lesion); Ix = ring-enhancing lesion; Mx = craniotomy w/ IV ceftriaxone + metronidazole
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95
Q

SUMMARY CARD:

What is prion disease and what are the 3 different types?

sporadic (demented LAMB), genetic (2 types), acquired (moo)

A

1. Sporadic: codon 129 – MM polymorphism

  • Demented LAMB =lower motor neuron signs, akinetic mutism, myoclonic jerks and cortical blindness)
  • EEG = periodic triphasic sharp wave complexes
  • LP = 14-3-3 + S100 protein
  • Autopsy= spongiform vacuolation, PrP amyloid plaques

2. Genetic: PRNP P102L (GSS syndrome)/PRNP D178N (FFI) –> TWO types:

  • Gerstmann-Strausslet-Sheinker syndrome: ADD = slowly progressive ataxia, diminished reflexes, dementia
  • Familial fatal insomnia: untreatable insomnia (agrypnia excitata), dysautonomia, late cognitive decline, die from lack of sleep

3. Acquired: variant – Bohvine-Johne’s Disease in cows (Mad Cow Disease)

  • Young patients
  • Psychiatric Sx e.g. anxiety, paranoia and hallucinations, then dementia
  • Ix: tonsillar biopsy (gold-standard), pulvinar sign (nuclei in thalamus)
  • Autopsy = florid plaques
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96
Q

SUMMARY CARD:

CSF analysis for the different causative organisms of meningitis:
1. appearance
2. glucose
3. white cells
4. cell type
5. other

bacterial, partially treated bacterial, viral, TB

A
  • Bacterial: turbid CSF, LOW glucose, HIGH WCC (polymorphs AKA neutrophils)
  • Partially treated bacterial: turbid CSF, NORMAL glucose, HIGH WCC (polymorphs AKA neutrophils)
  • Viral: clear CSF, NORMAL glucose, HIGH WCC (mononuclear AKA lymphocytes)
  • TB: clear or turbid CSF, VERY LOW glucose, HIGH WCC (mononuclear AKA lymphocytes)
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97
Q

DISEASE:

2 month infant w/ fever, irritability, poor feeding, and lethargy
LP = turbid, ↓ glucose, ↑ neutrophils

  1. diagnosis + possible causative organisms?
  2. Mx?

BONUS: what test is done to identify the organism?

A
  1. bacterial meningitis (due to ↑ neutrophils in CSF) –> < 3 months so could be neisseria meningitidis, streptococcus pneumoniae OR listeria
  2. Mx = IV ceftriaxone AND ampicillin (for listeria cover)

BONUS: gram stain for bacterial causes

meow

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98
Q

DISEASE:

Unvaccinated child
recently recovered for parotitis (inflammed parotid glands)
S&S now = fever, headache, photophobia, lethargy
Kernig’s sign +ve
CSF: lymphocytic pleocytosis (aka ↑ lymphocytes)

  1. diagnosis + causative organism?
  2. Ix?
  3. Mx?
A
  1. viral meningitis (due to↑ lymphocytes in CSF) –> most likely due to mumps virus (unvaccinated, parotitis)
  2. Ix = IgM mumps detection
  3. Mx = supportive usually for viral

NOTE: could give IV aciclovir if herpes cause

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99
Q

DISEASE:

22F went to subsaharan africa with friends 3 weeks ago
Cough + haemoptysis
Now S&S = fever, +ve Kernig’s sign, headache, photophobia
CSF = clear, ↓↓↓ glucose, ↑ lymphocytes

  1. diagnosis + causative organism?
  2. Ix?
  3. Mx?
A
  1. TB meningitis –> mycobacterium tuberculosis (due to ↓↓↓ glucose, ↑ lymphocytes)
  2. Ziehl-Neelson = stain carbol fuschin & methylene blue –> AFB go red on a blue background
  3. Mx = dexamethasone w/ anti-TB drugs
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100
Q

DISEASE:

45M - 3/7 seizures, confusion, fever, photophobia
MRI: temporal + inferior frontal lobe involvement

  1. diagnosis + causative organism?
  2. Mx?
A
  1. encephalitis –> HSV1 (most common)
  2. IV aciclovir
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101
Q

DISEASE:

4M - travelled to Afghanistan 2 weeks ago
Not immunised
Sensitivity to touch, muscle spasms –> progressed to paralysis

  1. most likely diagnosis + causative organism?

BONUS: when are kids vaccinated for this virus usually?

A

(polio)myelitis –> poliovirus

Normally, IPV (inactive polio vaccine) given as a part of 6 in 1 (2, 3, 4 months), 4 in 1 (3yrs + 4months), and 3 in 1 (14 years)

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102
Q

DISEASE:

30M - recent puncture wound in foot
IVDU
Severe muscle spasms + jaw stiffness (unable to open mouth)
Arched back (opisthotonos)

  1. diagnosis + causative organism?
  2. Mx?
A
  1. Tetanus –> clostridium tetani
  2. Mx = metronidazole
103
Q

DISEASE:

50M - 1/12 hx of dull persistent headache + intermittent fever + weakness in right arm & leg

  1. diagnosis + causative organism?
  2. Ix?
  3. Mx?

Ix - what is seen on brain MRI / CT?

A
  1. Brain abscess –> strep or staph
  2. Brain MRI = ring-enhancing lesion
  3. Mx = craniotomy w/ IV ceftriaxone + metronidazole
104
Q

DISEASE:

65M - rapidly progressive dementia (increasingly forgetful, struggling to speak)
blindness w/ normal pupillary reflexes to light
myoclonic jerks
decreased reflexes

  1. most likely diagnosis?
  2. What is seen on EEG / LP / autopsy?

EEG = tri; LP = protein; autopsy = plaques

A

1. Sporadic prion disease
NOTE: Sx = demented LAMB =lower motor neuron signs, akinetic mutism, myoclonic jerks and cortical blindness)
NOTE: cortical blindness is loss of vision w/o opthalmologic cause and preserved pupillary light reflexes

  1. EEG = periodic triphasic sharp wave complexes; LP = 14-3-3 + S100 protein; autopsy = spongiform vacuolation, PrP amyloid plaques
105
Q

DISEASE:

42f - ataxia, diminished reflexes, and cognitive decline (dementia) over the past year
FHx of progressive neurological symptoms

  1. diagnosis?
A

Genetic Gerstmann-Strausslet-Sheinker (one of the genetic prion diseases)

106
Q

DISEASE:

55F - 3/12 hx of worsening insomnia
Tried relaxation therapies, melatonin tablets, no screen time 4 hours before bed etc.
FHx of this leading to madness –> death
Genetic testing: PRNP D178N mutation

  1. diagnosis?
A

Familial fatal insomnia (UNTREATABLE insomnia)

107
Q

DISEASE:

30M - worsening anxiety, paranoia, + auditory & visual hallucinations
Exhibits cognitive decline
HPC: consumed beef products

  1. diagnosis?
  2. Ix - gold standard?
  3. Autopsy?
A
  1. variant of Bohvine-Johne’s Disease AKA Mad Cow Disease (acquired prion disease)
  2. Tonsillar biopsy –> abnormal prions (gold standard)
    note: can also do MR –> pulvinar sign (nuclei in thalamus)
  3. Autopsy = florid plaques
108
Q

SUMMARY CARD:

Name possible STIs based on presentation:
1. Discharge
2. Ulceration
3. Rashes, lumps/growths

A
  1. Discharge: gonorrhoea, chlamydia, trichomonas, candida, BV
  2. Ulceration: syphilis (painless chancre), chancroid, LGV, donovanosis
  3. Rashes, lumps/growths: genital warts (HPV 6 & 11), molluscum contagiosum, scabies, pubic lice
109
Q

SUMMARY CARD:

Name the causative organisms (+ Sx / Ix / Mx) of the following bacterial STIs:
1. Gonorrhoea
2. Genital chlamydia
3. Lympho-granuloma venereum
4. Syphilis
5. Chancroid
6. Donovanosis
7. Bacterial vaginosis

A

1. Gonorrhoea –> neisseria gonorrhoea (gram -ve cocci)

  • Urethritis / cervicitis, discharge, dysuria (rectal prostitis if MSM)
  • Mx = ceftriaxone

2. Genital chlamydia –> chlamydia trachomatis (-ve coccobacilli)

  • Often asymptomatic (esp. in women, so 1st presentation may be PID / infertility)
  • Yellow / green discharge
  • Serovars D-K cause genital chlamydia
  • NAAT (nucleic acid amplification test) from genital swabs / first void urine confirms diagnosis
  • Mx = doxycycline 100mg BD 7 days OR 1g azithromycin stat (e.g. in pregnancy because doxy is teratogenic)

3. Lympho-granuloma venereum –> chlamydia trachomatis (-ve coccobacilli) causes lymphatic infection

  • Serovars L1, L2 and L3
  • 3 stages: painless ulcer/papule on genitals; then painful inguinal lymphadenopathy; then proctocolitis
  • Dx = +ve urinary NAAT
  • Mx = doxycycline

4. Syphilis –> treponema pallidum (-ve spirochaete)

  • 1° = PAINLESS ULCER (chancre)
  • 2° = widespread rash + ”snail track” ulcers + condyloma acuminate (genital warts, hypopigmented lesions)
  • 3° = THREE different syndromes: gumma (gum-like pus lesion); CVS e.g. ascending aortic aneurysm (AAA), neurosyphilis e.g. arygyll-Robertson pupil + dementia + tabes dorsalis (spinal cord)
  • Spirochaetes in CSF in 3° syphilis
  • Ix = dark-field microscopy (for 1° chancre) shows treponemes
  • Treponemal = detects Abs against specific antigens which stays +ve long term even after Tx VS non-treponemal tests = detects Abs against non-specific antigens and titres fall w/ effective Tx
  • Mx = benzathine benzylpenicillin IM (doxy if allergic) – monitor with RPR titres + can cause Jarisch-Herxheimer reaction (rash, hypotension, fever)

5. Chancroid –> haemophilus ducreyi (-ve coccobacilli)

  • PAINFUL ulcer
  • unilateral painful inguinal lymphadenopathy
  • Ix = chocolate agar

6. Donovanosis –> klebsiella granulomatis (-ve bacilli)

  • Beefy red ulcers
  • Ix = Giemsa stain –> donavan bodies
  • Mx = azithromycin

7. Bacterial vaginosis –> gardnerella vaginalis (gram variable)

  • Smelly white creamy discharge
  • Ix: Amsel criteria (clue cells, pH >4.5, whiff test, abnormal vaginal discharge)
  • Mx: metronidazole (even in pregnancy)
110
Q

SUMMARY CARD:

Name the causative organisms (+ Sx / Ix / Mx) of the following STIs:
1. Trichomoniasis
2. Candidiasis
3. Molluscum contagiosum
4. Genital warts
5. Examples of viral STIs

A

1. Trichomoniasis –> trichomonas vaginalis (flagellated protozoa)

  • Men = asymptomatic usually (?urethritis); women = yellow/green discharge, offensive smelling
  • pH >4.5 (NOTE: BV is the only other condition w/ pH >4.5 asw)
  • Ix = speculum –> strawberry cervix
  • Ix = wet slide microscopy (motile trophozoites)
  • Mx = metronidazole
  • Associated w/ ↑ risk of HIV due to disrupted mucosa

2. Candidiasis/ thrush –> candida albicans (yeast)

  • ‘Cottage cheese’ (thick white) discharge
  • Mx = oral fluconazole (BUT cream / pessaries ONLY if pregnant, oral contraindicated)

3. Molluscum contagiosum –> poxvirus

  • Small papules w/ central punctum (widespread if immunocompromised)
  • Children: spread by skin-to-skin contact, spots on hands & face
  • Adults: spread via sexual contact, genital lesions
  • Supportive Mx / cryotherapy if persistent

4. Genital warts –> HPV 6 & 11

  • Mx = podophyllotoxin solution / cream (CI pregnancy); 2nd line = cryotherapy in clinic or Imiquimod

5. Examples of viral STIs:

  • Hepatitis, HBV, HCV (mainly in HIV +ve MSM), herpes, HIV
111
Q

DISEASE:

Unprotected intercourse w/ multiple partners
purulent yellow/green discharge from urethra
NAAT = gram -ve cocci

  1. diagnosis + causative organism?
  2. Mx?
A
  1. Gonorrhoea (due to neisseria gonorhoea)
  2. Mx = ceftriaxone
112
Q

DISEASE:

33F - recently changed partners
lower abdo pain + greyish white vaginal discharge
cervical excitation on bimanual

  1. diagnosis + causative organism?

BONUS: gram stain of organism?

  1. Mx?
A
  1. PID (due to chlamydia trachomatis)

BONUS: gram -ve coccobacilli

  1. Doxycycline 100mg BD 7 days (azithromycin 1g stat if pregnant)
113
Q

DISEASE:

Started off as painless ulcers on genitals, then developed painful inguinal lymphadenopathy
Now rectal discomfort –> inflammation of the anus & colonic mucosa (proctocolitis)

  1. diagnosis + causative organism?
  2. which specific serovars of the organism cause this?
  3. Mx?
A
  1. Lymphogranuloma venereum - LGV (due to chlamydia trachomatis) = infection in lymphatic system
  2. Serovars L1-L3
  3. Doxycycline 100mg BD 3 wks
114
Q

DISEASE:

15 years ago had painless genital ulcers (chancre) + rashes on palms + hypopigmental lesions (condyloma acuminate)
Now, tabes dorsalis + gum-like pus lesion + aortic root dilation

  1. diagnosis + causative organism?
  2. Ix?
  3. Mx?
A
  1. currently has 3° syphilis (due to treponema pallidum)

NOTE: Sx from 15 years ago are 1° + 2°
Currently pt has gumma (gum-like pus lesion) + spinal cord involvement (tabes dorsalis) + CVS involvement (AAA) = 3°

  1. Ix = dark-ground microscopy to see chancre (treponemes seen)
    for 3°, Ix = non-treponemal test (tests for Abs against non-specific antigens as the titres go down after Tx)

NOTE: treponemal test looks for Abs against specific antigens and this stays +ve for many years even after successful Tx

  1. Mx = single dose IM benpen (benzathine benzylpenicillin
115
Q

DISEASE:

32M - PMHx = syphilis, comes in for follow-up after initiating treatment with benzathine benzylpenicillin
Now has fever, chills, headache, + myalgia
low BP

  1. what is this reaction called?

JH

A

Jarisch-Herxheimer reaction

116
Q

DISEASE:

painful genital ulcer
painful R sided (unilateral) inguinal lymphadenopathy

  1. diagnosis + causative organism?
  2. what type of agar is it cultured on?

makes you cry; nom nom nom

A
  1. chancroid (due to haemophilus ducreyi = -ve coccobacilli)
  2. chocolate agar
117
Q

DISEASE:

beefy red ulcers
Giemsa staining of ulcer swabs reveals Donovan bodies; -ve bacilli

  1. diagnosis + causative organism?
  2. Mx?
A
  1. Donovanosis (due to klebsiella granulomatis)
  2. Azithromycin
118
Q

DISEASE:

smelly white creamy discharge after using fem hygiene soaps to clean the vagina

  1. diagnosis + causative organism?
  2. Ix?
  3. Mx?

cinderalla got this; criteria?

A
  1. Bacterial vaginosis (due to gardnerella vaginalis)
  2. Amsel criteria: clue cells, pH >4.5, whiff test, abnormal vaginal discharge
  3. Mx: metronidazole (even in pregnancy)
119
Q

DISEASE:

yellow/green discharge
strawberry cervix

  1. diagnosis + causative organism?
  2. Ix?
  3. Mx?

BONUS: associated with increased risk of which infection?

A
  1. Trichomoniasis (due totrichomonas vaginalis, a flagellated protozoa)
  2. Ix = wet slide microscopy –> motile trophozoites
  3. Mx = metronidazole

BONUS: associated w/ ↑ risk of HIV due to disrupted mucosa

120
Q

DISEASE:

cottage cheese thick white discharge after starting fem hygiene soaps
pruritic vulva / vagina (vulvovaginitis)

  1. diagnosis + causative organism?
  2. Mx?
A
  1. candidiasis (due to candida albicans, yeast)
  2. oral fluconazole (unless pregnant, then pessary / topical)
121
Q

DISEASE:

Small papules w/ central punctum
not itchy, apyrexial
widespread if immunocompromised

  1. diagnosis + causative organism?
  2. Mx?
A
  1. molluscum contagiosum
  2. supportive Mx (cryotherapy if persistent)
122
Q

DISEASE:

25F = missed her HPV vaccine in secondary school
new sexual partner last month
painful genital lesions

  1. diagnosis + causative organism(s)?
  2. Mx?
A
  • Genital warts (caused by HPV 6 & 11, which are normally in the HPV vaccine given at 13 years)

NOTE: oncogenic types are HPV 16 and 18

  • Mx = podophyllotoxin solution / cream (CI pregnancy); 2nd line = cryotherapy in clinic or Imiquimod
123
Q

SUMMARY CARD:

What are the causative organisms of each of the following zoonoses:

  1. Malaria
  2. Typhoid
  3. Dengue
  4. Spotty rocky mountain fever
  5. Rabies
  6. Q fever
  7. Brucellosis
  8. Leptospirosis
  9. Lyme disease
  10. Human plague
  11. Anthrax
  12. Leishmaniasis
  13. Sleeping sickness
  14. Catch scratch disease
A
  1. Malaria: malariae falciparum (most common), vivax, ovale, knowlesi, malariae
  2. Typhoid: salmonella typhi = gram -ve bacilli
  3. Dengue: flavivirus
  4. Spotty rocky mountain fever: rickettsial akari = gram -ve coccobacilli
  5. Rabies: rhabdovirus
  6. Q fever: coxiella burnetti (BBQ –> CBQ –> house of CB –> coxiella burnetti) = gram -ve coccobacilli
  7. Brucellosis: brucella miletensis = gram -ve coccobacilli
  8. Leptospirosis: leptospira interrogans = gram -ve spirochete
  9. Lyme disease: borrelia burgdorferi = gram -ve spirochete (Avril lavigne –> babiest baby –> BB –> borrelia burgdorferi)
  10. Human plague: yersinia pestis = gram -ve bacilli (yessir pestis)
  11. Anthrax: bacillus anthrax that release a tripartite protein toxin = gram +ve rods
  12. Leishmaniasis: leishmania major/tropica (most common); donovani (Kala Azar)
  13. Sleeping sickness: trypanosoma brucei and Trypanosoma cruzi (Chagas)
  14. Catch scratch disease: bartonella henselae = gram -ve bacilli (cats? chickens? henselae)
124
Q

SUMMARY CARD:

  • What are the features of malaria?
  • How does it spread (vector)?
  • How is it diagnosed and managed?
  • BONUS: what fever is a complication of malaria falciparum?
A
  • Plasmodium falciparum, vivax, ovale, knowlesi, malariae
  • Female anopheles mosquito
  • Endemic regions / recent travel (PUO in returning traveller from endemic region)
  • TIP: Ask if pt took malaria prophylaxis
  • Cyclical fevers (every 48 hrs in falciparum/vivax/ovale and 72 hrs in malariae)
  • NOTE: can also get cerebral malaria –> leads to coma
  • Sx of severe falciparum malaria = impaired conscious / seizures, renal impairment, acidosis, hypoglycaemia, pulmonary oedema, anaemia, DIC, shock, haemoglobinuria (without G6PDD)
  • NOTE: HLA-B53 is protective against severe malaria
  • Thick and thin blood films = 3x thick (to check for parasites) and thin (to quantify parasitaemia + demostrate the species; if >2% in children or >10% in adults –> severe)
  • Falciparum = Maurer’s clefts in RBCs
  • Ovale + Vivax = Schuffner dots in RBCs
  • Mx for Falciparum = oral malarone / IV artesunate (if severe)
  • Mx for Ovales + Vivax + Malariae = chloroquine
  • NOTE: antimalarials can cause acute haemolysis in people with G6PDD

BONUS: blackwater fever severe complication of plasmodium falciparum malaria characterised by haemoglobinuria (AKA dark urine –> ‘blackwater’)

125
Q

SUMMARY CARD:

  • What are the features of typhoid fever?
  • How does it spread?
  • How is it diagnosed and managed?
  • BONUS: can you vaccinate against this?
A
  • Salmonella typhi (or paratyphi) = gram -ve bacilli
  • Faeco-oral spread (contaminated food / water) - 1-2 wks incubation
  • Enteric fever (fever + GI Sx) –> due to Peyer’s patches
  • High prolonged fever + headache
  • Constipation > diarrhoea
  • Rose spots
  • Relative bradycardia (AKA Faget sign) –> with high temperature you expect ↑HR, but pt actually has normal HR
  • GOLD STANDARD = blood culture (+/- stool culture)
  • Mx = IV ceftriaxone, then PO azithromycin

BONUS: typhoid vaccine vaccinates against S. typhi

126
Q

SUMMARY CARD:

  • What are the features of dengue?
  • How does it spread?
  • How is it diagnosed and managed?
  • BONUS: what other types of dengue can you get?
A
  • Flavivirus
  • Female aedes mosquito - short incubation period (days)
  • SE asia, urban environments
  • NOTE: rare in travellers (unlike malaria) as uncommon to be re-infected
  • Sx: fever, myalgia, sunburn rash, retroorbital headache
  • Fever then fucked (critical) before recovery
  • Ix = ↓Hb, ↓WCC, ↓platelets
  • Councilman bodies (inclusion bodies) in hepatocytes
  • Supportive Mx

BONUS: dengue haemorrhagic fever = ↑ bleeding; dengue shock syndrome = ↓ BP

127
Q

SUMMARY CARD:

  • What are the features of ** Rocky Mountain spotted fever**?
  • How does it spread?
  • How is it diagnosed and managed?
A
  • Rickettsial akari - gram negative coccobacilli
  • Liponyssoides sanguineus (tick)
  • Fever + headache + rash that starts peripherally (maculopapular to vasculitic)
  • Myalgia
  • Black eschars
  • Mx = doxycycline
128
Q

SUMMARY CARD:

  • What are the features of rabies?
  • How does it spread?
  • How is it diagnosed and managed?

BONUS: what is found in the infected neurons?

A
  • Lyssa virus / rhabdovirus
  • Dogs or bats
  • Prodrome: fever + headache + sore throat
  • Migration to CNS (after months - years) = hypersalivation, hydrophobia, acute encephalitis (agitation, seizure)
  • NOTE: nearly 100% mortality once CNS Sx
  • Therefore, MUST take prophylactic rabies vaccine! –> rabies IgG post-exposure vaccination course
  • Ix = IgM

BONUS: negri bodies in infected neurons

rabies = rhabovirus

129
Q

SUMMARY CARD:

  • What are the features of Q fever?
  • How does it spread?
  • How is it diagnosed and managed?

BONUS: what is found in the infected neurons?

house of CB

A
  • Coxiella burnetti = gram -ve coccobacilli
  • Cattle / sheep
  • Fever
  • Atypical pneumonia (dry cough) or endocarditis
  • CXR = ground-glass appearance
  • Ix = serology
  • Mx = doxycycline
130
Q

SUMMARY CARD:

  • What are the features of brucellosis?
  • How does it spread?
  • How is it diagnosed and managed?

BONUS: what are the complications (HINT: MEOw)?

anti-O-polysaccharide antibody

A
  • Brucella melitensis = gram -ve bacilli
  • Unpasteurised dairy, direct animal contact (farmers)
  • SUDDEN onset ↑ fever
  • Returning traveller with orchitis + back pain (sacroiliitis) with psoas + liver abscesses
  • Brucella serology: anti-O-polysaccharide antibody
  • Castenada’s medium
  • Mx = 4-6 weeks of doxycycline + gentamicin/streptomycin
  • Complications = MEO(W): meningoencephalitis, endocarditis, osteomyelitis
131
Q

SUMMARY CARD:

  • What are the features of leptospirosis?
  • How does it spread?
  • How is it diagnosed and managed?

BONUS: what are the symptoms of severe disease?

Hint: interrogate; weil’s disease

A
  • Leptospiroma interrogans = gram -ve spirochaete
  • Rat urine
  • Fever + jaundice + conjunctival haemorrhages
  • RFs = sewage workers, farmers
  • Mx = doxycycline (or erythromycin)
    BONUS: in severe disease (Weil’s disease) = AKI, aspetic meningitis
132
Q

SUMMARY CARD:

  • What are the features of lyme disease?
  • How does it spread?
  • How is it diagnosed and managed?

Hint: babiest baby (BB) loves avril lavigne –> BB = ?

A
  • Borrelia burgdorferi = spirochaete
  • Ixodes ticks –> RFs = hiking
  • EARLY (localised) = bull’s eye rash (erythema chronicum migrans), flu-like Sx
  • EARLY disseminated = fevers, myalgia, arthralgia, CNS/heart block Sx
  • LATE (persistent) = carditis, malaise, meningitis, 3rd degree heart block / CNS signs
  • Ix: ELISA to BB then immunoblot
  • Mx = doxycycline (amoxicillin in pregnancy OR ceftriaxone if disseminated)
133
Q

SUMMARY CARD:

  • What are the features of human plague?
  • How does it spread?
  • How is it diagnosed and managed?

Yessir pestis; causes dry gangrene slowly

A
  • Yersinia pestis = gram -ve bacilli, lactose fermenter
  • Rats = resevoir, transmission by fleas
  • NOTE: still seen in some American national parks e.g. Yosemite
  • Swollen LN = bubo
  • Dry gangrene
  • Ix = PCR
  • Mx = causes dry gangrene slowly: chloramphenicol + doxycycline + gentamicin + streptomycin
134
Q

SUMMARY CARD:

  • What are the features of athrax?
  • How does it spread?
  • How is it diagnosed and managed?
A
  • Bacillus anthracis = gram +ve rods with tripartite protein toxin
  • Cows
  • Cutaneous = painless black eschars
  • Pulmonary = massive lymphadenopathy + mediastinal haemorrhage (CP + SOB + haemoptysis)
  • GI = necrotic ulcers, perforation
  • Mx = doxycycline / ciprofloxacin
135
Q

SUMMARY CARD:

  • What are the features of leishmaniasis?
  • How does it spread?
  • How is it diagnosed and managed?

3 types: cutaenous, muco-cutaneous, + visceral

A
  • Leishmania major/tropica (most common) = causes cutaenous
  • Leishmania brazilensis = muco-cutaenous
  • Leishmania donovani = causes visceral
  • Sandfly
  • Cutaneous (most common) = scaly ulceration at sandfly bite site
  • Muco-cutaenous = starts off as dermal ulcer, then months-years later ulcerative mucous membrane destruction in nose / mouth
  • Visceral (Kala Azar) = massive splenomegaly, usually young malnourished child, gradual onset fever, abdo discomfort, anorexia / weight loss
  • Ix: NMN (Novy-Macneal-Nicolle); splenic aspirate
  • Mx = amphotericin B
136
Q

SUMMARY CARD:

  • What are the features of sleeping sickness?
  • How does it spread?
  • How is it diagnosed and managed?

2 types of brucei = GG + RR

A
  • Trypanosoma brucei and Trypanosoma cruzi (chagas)
  • NOTE: African sleeping sickness = Brucei gambiense
  • Tsetse fly (sleeping sickness)
  • Brucei gambiense (African) = gradual infection (GG)
  • Brucei rhodesiense = rapid infection (RR)
  • Cruzi = acutely Romana’s sign (purple eyelid); chronically dysphagia due to formation of megaoesophagus and megacolon
  • Mx (early disease) = IV pentamidine; later disease = IV melarsoprol
137
Q

SUMMARY CARD:

  • What are the features of cat scratch disease?
  • How does it spread?
  • How is it diagnosed and managed?

cat –> chicken –> hen

A
  • Bartonella henselae = gram -ve bacilli
  • Kitties
  • NOTE: cat scratch disease is a severe form of bacillary angiomatosis (a cutaneous infection caused by bartonella)
  • RFs = immunocompetent
  • Macule at site of bite
  • Mx = erythromycin/doxycycline
138
Q

DISEASE:

23M - recently returned from medical elective in Africa
1/52 Hx of of fever + myalgia + headaches

What diagnostic investigation should be requested?

A

Thick + thin blood films
* 3x thick = to check for parasites
* Thin = to quantify parasitaemia + demostrate the species; if >2% in children or >10% in adults –> severe

139
Q

DISEASE:

What is the management of severe malaria?

BONUS: if a patient develops haemoglobinuria - what is the complication called?

A

IV artesunate

BONUS: blackwater fever

140
Q

DISEASE:

BONUS q:
Most common cause of neutropenic sepsis in PUO?

haven’t covered this yet

A

Pseudomonas

141
Q

DISEASE:

20F - Enteric fever (AKA fever + GI Sx)
Constipation
Rose spots
Relative bradycardia

  1. Diagnosis (+ causative organism)?
  2. How does it spread?
  3. Ix?
  4. Mx?
A
  1. Typhoid fever –> salmonella typhi (or paratyphi)
  2. faeco-oral (contaminated food)
  3. Ix = blood culture +/- stool culture (GOLD STANDARD)
    Mx = IV ceftriaxone, then PO azithromycin
142
Q

DISEASE:

25F - severe headache, retro-orbital pain, myalgia + maculopapular rash
Fever
Travelled SE asia
leukopenia + thrombocytopenia

  1. Diagnosis (+ pathogen)?
  2. Vector?
  3. What is seen on microscopy of the liver?
  4. Mx?

hint: inspection of liver

A
  1. Dengue fever = flavivirus
  2. Female aedes mosquito
  3. Councilman bodies in hepatocytes
  4. Supportive Mx
    NOTE: bloods show ↓Hb, ↓WCC, ↓platelets
143
Q

DISEASE:

50M - returned from hiking trip 1/52
fever + headache + myalgia
Maculopapular rash on wrists + ankles initially, now spread to trunk
Black dots on skin

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Mx?

rocky = rickets

A
  1. Rocky Mountain Spotted Fever = rickettsial akari
  2. Ticks (liponyssoides sanguineus)
  3. Sx = fever + headache + rash that starts peripherally (maculopapular to vasculitic) + black eschars
  4. Mx = doxycycline
144
Q

DISEASE:

55M - homeless man w/ agitation, confusion, and hydrophobia
Bitten by dog 1 month ago
febrile + hypersalivation

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Mx?
A
  1. Rabies = rhabdovirus
  2. Dogs or bats
  3. 100% mortality if CNS S&S

NOTE: normally give prophylactic vaccination course with IgG

145
Q

DISEASE:

33F - farmer
2/52 Hx of high fever + severe headache + myalgia, + non-productive cough
Helped deliver livestock 2/52 ago
febrile + mild hepatomegaly

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Ix?
  4. Mx?
A
  1. Q fever = coxiella burnetti
  2. Cattle (farmers at risk, esp with fluid transmission)
  3. CXR = ground glass appearance (due to atypical pneumonia presentation); serology
  4. Mx = doxycycline
146
Q

DISEASE:

32M - recent trip to cheese factory + ate unpasteurised cheese
sudden onset fever
orchitis
back pain (sacroiliitis)

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Ix?
  4. Mx?
A
  1. Brucellosis = brucella melitensis
  2. unpasteurised dairy / farm animals
  3. Ix = brucella serology; anti-O-polysaccharide antibody (NOTE: castenada medium)
  4. Mx = doxycycline + gentamicin
147
Q

DISEASE:

60M - 4/7 flu-like Sx
myalgia + abdo pain + jaundice
retro-orbital headaches + conjunctival haemorrhages
febrile
ECG + U&Es normal

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Mx?

BONUS: what is the severe form of this disease called?

interrogate on elective

A
  1. Leptospirosis = leptospiroma interrogans
  2. rat urine
  3. Mx = doxycycline

BONUS: Weil’s disease (presets with AKI + aseptic meningitis)

148
Q

DISEASE:

38F - recent hiking trip
fever + myalgia + arthralgia
ECG shows 3rd degree heart block

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Ix?
  4. Mx?
A
  1. Lyme disease = borrelia burgdorferi
  2. Ixodes ticks
  3. Ix = ELISA
  4. Mx = doxycycline

NOTE: bull’s eye rash (erythema chronicum migrans) is seen in EARLY disease (pt is presenting with late S&S)

149
Q

DISEASE:

Cause of human plague + management?

yessir

A
  • Yersinia pestis
  • RFs = Yosemite (reside in rats, spread by fleas)
  • Mx = causes dry gangrene slowly –> chloramphenicol + doxycycline + gentamicin + streptomycin

NOTE: enlarged LNs called buboes (AKA bubonic plague)

150
Q

DISEASE:

45M - painless black eschars
farmer
now presenting with CP + SOB + haemoptysis

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Ix?
  4. Mx?
A
  1. Anthrax = bacillus athracis
  2. Cows
  3. CXR = mediastinal haemorrhage; colonoscopy = GI ulcers + perforation
  4. Mx = doxycycline / ciprofloxacin
151
Q

DISEASE:

35F - non-healing scaly ulceration at bite site

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Ix?
  4. Mx?
A
  1. Leishmaniasis (cutaenous = leishmania major/tropica)
  2. Sandfly
  3. Ix: NMN (Novy-Macneal-Nicolle); splenic aspirate
  4. Mx = amphotericin B
152
Q

DISEASE:

How is sleeping sickness spread?
What is the causative organism for:
1. gradual fever onset?
2. rapid fever onset?
3. purple eyelid + chronic dysphagia?

A
  • Tsetse fly
  1. Trypanosoma brucei gambiense (African) = gradual infection (GG)
  2. Trypanosoma brucei rhodesiense = rapid infection (RR)
  3. Trypanosoma cruzi = acutely Romana’s sign (purple eyelid); chronically dysphagia due to formation of megaoesophagus and megacolon
153
Q

DISEASE:

8F - playing with new kitten
macule at bite site

  1. Diagnosis (+ causative organism)?
  2. Vector?
  3. Mx?
A
  • Cat scratch disease = bartonella henselae
  • Cats
  • Mx = doxycycline
154
Q

SUMMARY CARD:

What are the causative organisms of the following worms:

  1. Tapeworm from pork
  2. Tapeworm from beef
  3. Tapeworm from dogs
  4. Schistomiasis
  5. Ascariasis
  6. Hookworm infection
  7. Threadworm
  8. Strongyloidiasis
  9. Elephantiasis
  10. Onchocerciasis (or river blindness)
A
  1. Tapeworm from pork = taeniae solium
  2. Tapeworm from beef = taeniae saginata
  3. Tapeworm from dogs = echinococcus granulosus
  4. Schistomiasis = schistosoma haematobium (flukes)
  5. Ascariasis = ascaris lumbricoides (roundworm)
  6. Hookworm infection = ancyclostoma duodenale (roundworm)
  7. Threadworm = enterobius vermicularis (sounds italian)
  8. Strongyloidiasis = strongyloides stercoralis (roundworm)
  9. Elephantiasis = wuchereria bancrofti (roundworm)
  10. Onchocerciasis (or river blindness) = onchocerca volvulus (roundworm)
155
Q

SUMMARY CARD:

What are the S&S (+/- Ix +/- Mx) of each of the following tapeworms:

  1. From pork
  2. From beef
  3. From dogs

solium, saginata, lots of c’s for liver cysts

A
  1. Tapeworm from pork (taeniae solium)
    AND 2. from beef (taeniae saginata):
  • Mass lesions in the brain w/ swiss cheese appearance
  • Mx: -bendazoles
  1. Tapeworm from dogs (echinococcus granulosus):
  • Liver cysts
  • If cyst ruptures, then anaphylactic like reaction
  • Mx = -bendazoles
156
Q

SUMMARY CARD:

What are the S&S (+/- Ix +/- Mx) of each of:

  1. Flukes
  2. Threadworms
A
  1. Flukes = schistosoma haematobium (AKA schistomiasis)
  • Itchy rash + painless haematuria
  • RFs = swimming
  • Katayama fever (fever, rash, myalgia, hepatosplenomegaly)
  • Bladder calcification
  • ↑ risk of bladder SCC
  • Mx: Praziquantel (increases permeability towards Ca2+)
  1. Threadworms = enterobius vermicularis
  • Perianal itching especially at night
  • Vulval symptoms in females
  • Ix = sticky plastic tape to perianal area
  • Mx = mebendazole for patient + family members
157
Q

SUMMARY CARD:

What are the S&S (+/- Ix +/- Mx) of each of the following roundworms:

  1. Ascariasis
  2. Hookworm
  3. Strongyloidiasis
  4. Elephantiasis
  5. Onchocerciasis
A
  1. Ascariasis = ascaris lumbricoides
  • Soil transmitted helminth (giant roundworm)
  • Intestinal obstruction
  • Loffler’s syndrome = eosinophilic pneumonia
  1. Hookworm infection = ancyclostoma duodenale
  • Larvae penetrate skin of feet (transdermal)
  • Causing GI infections (which lead to anaemia as worms attach to the intestinal wall + feed on blood, causing chronic intestinal blood loss)
  • Mx = albendazole, mebendazole
  1. Strongyloidiasis = strongyloides stercoralis (roundworm)
  • Diarrhoea + abdominal pain
  • Papulovesicular lesions where the skin has been penetrated by infective larvae, larva currens
  • Mx = ivermectin (activated glutamate-gated chloride channels)
  1. Elephantiasis = wuchereria bancrofti
  • Transmission by female mosquito
  • Causes blockage of lymphatics → fluid accumulation + swelling (elephantiasis)
  • Mx = dietylcarbamazine (inhibits arachidonic acid metabolism)
  1. Onchocerciasis (or river blindness) = onchocerca volvulus
  • **River blindness **(visual impairment due to ocular lesions + inflammation) + hyperpigmented skin
  • Allergic reaction to microfilaria (AKA larvae)
  • Mx = IVERmectin for rIVERblindness
158
Q

DISEASE:

What is the characteristic appearance of brain lesions caused by Taeniae solium and Taeniae saginata infection?

A

swiss cheese

159
Q

DISEASE:

Burst liver cyst causes anaphylactic-like reaction

  1. Diagnosis?
  2. Mx?
A
  • Tapeworm infection = echinococcus granulosus
  • Mx = mebendazole
160
Q

DISEASE:

Itchy rash after swimming
fever + hepatosplenomegaly

  1. diagnosis?
  2. Mx?

BONUS: ↑ risk of which cancer?

A
  1. Schistomiasis = schistosoma haematobium (flukes)
  2. Mx = Praziquantel

BONUS: ↑ risk of bladder cancer

161
Q

DISEASE:

Which syndrome, characterized by eosinophilia pneumonia, is associated with ascaris lumbricoides infection?

A

Loeffler’s syndrome

162
Q

DISEASE:

How do larvae of ancyclostoma duodenale typically enter the human body

(AKA hookworm)

A

Hookworm –> penetration through the skin

163
Q

DISEASE:

What is the primary symptom of Enterobius vermicularis infection in children?

A

perianal itching

Mx = mebendazole for WHOLE household

164
Q

DISEASE:

What is the primary mode of transmission of strongyloides stercoralis infection to humans?

A

Penetration through skin

165
Q

DISEASE:

Elephantiasis is caused by which organism?

A

Wuchereria bancrofti

Mx = diethylcarbamazine

166
Q

DISEASE:

Which medication is the primary treatment for Onchocerca volvulus infection?

AKA river blindness

A

Ivermectin (cause river blindness)

167
Q

SUMMARY CARD:

What is the causative organism + Sx (+/- Ix +/- Mx) of the following superficial fungal infections?

  1. Athlete’s foot
  2. Tinea capitis
  3. Pityriasis versicolor
A

1. Athlete’s foot = tinea dermatophyte (ringworm)

  • Specifically trichophyton rubrum causes athlete’s foot
  • Scaly / peeling / cracked skin between toes
  • Mx = topical antifungal e.g. clotrimazole (oral considered if complex e.g. multiple sites of infection or toe nail infection)
  • NOTE: Potassium hydroxide mixed with nail/skin clippings is a decent diagnostic test for the presence of tinea or trycophyton

2. Tinea capitis = tinea dermaphyte on scalp (scalp ringworm)

  • Scaly + itchy patches + well defined patches of hair loss
  • Painful, swollen lymph nodes
  • Mx = systemic antifungals (e.g. terbinafine) + anti-fungal shampoos to reduce transmission
  • NOTE: always order LFTs before starting terbinafine as it is metabolised by the liver

3. Pityriasis versicolor = malassezia furfur

  • Flaky discolouration (hypopigmentation); asymptomatic
  • Microscopy = spaghetti + meatballs appearance
  • Wood’s Lamp = patches that fluoresce a faint orange colour
  • Mx = topical antifungal e.g. ketoconazole
168
Q

SUMMARY CARD:

What is the causative organism + Sx (+/- Ix +/- Mx) of the following deep seated fungal infections?

  1. Candidiasis
  2. Cryptococcis
  3. Histoplasmosis
  4. Aspergillosis
  5. Mucormycosis
  6. Onychomycosis
  7. Sporotrichosis
A

1. Candidiasis = candida albicans (yeast)

  • Deep-seated infections (e.g. oesophagitis = odynophagia) in the immunocompromised
  • ‘Cottage cheese’ like
  • Ix = Germ tube test (for albicans)
  • Mx = fluconazole (or amphotericin B for invasive disease)
  • NOTE: if non-albicans disease, use caspofungin (type of echinocandin)

2. Cryptococcis = cryptococcus neoformans (yeast)

  • Found in pigeon droppings
  • Main RF = immunosuppression
  • Sx = insidious onset meningitis in HIV
  • Ix = India ink stain → yeast cells surrounded by halos
  • Mx = amphotericin B

3. Histoplasmosis = histoplasma capsulatum

  • Found in bird / bat droppings
  • Causes chronic progressive lung disease (Sx = cough, chest pain, + fever)
  • Endemic to the Mississippi River region

4. Aspergillosis = aspergillus

  • Aspergillus flavus = stored grains/peanuts + produces aflatoxin that can lead to hepatocellular carcinoma
  • Ix = galactomannan ELISA (part of aspergillus cell wall)
  • Staining = methenamine silver stain
  • Mx = amphotericin B (longer course than cryptococcus)
  • Aspergillus fumigatus = causes allergic bronchopulmonary aspergillosis, aspergilloma, + invasive aspergillosis in those with cystic fibrosis
  • NOTE: its burkholderia cepecia that is CI for lung transplant in CF pts

5. Mucormycosis = rhizopus + mucor (AKA ‘black fungus’)

  • Black pus from nose/mouth
  • Very severe in immunocompromised/poorly controlled diabetes
  • Sx = cellulitis, necrotic destructive lesions around the face e.g. jaw
  • Mx = surgical debridement + amphotericin B

6. Onychomycosis

  • Thickened nails
  • Mx = Nail lacquers / turbinafine

7. Sporotrichosis = sporothrix schnekenii

  • Caused by rose pricks
  • RF = rose gardeners
  • Painless nodular lesion, rash + ascending lymphadenopathy
  • May lead to bone/joint/muscle involvement
169
Q

DISEASE:

What organism causes athlete’s foot?

BONUS: if the infection is in the nails, what test can you do for a quicker result than culture?

A

Trichophyton rubrum

BONUS: KOH → mixed with nail/skin clippings can test for presence of tinea or trycophyton

170
Q

DISEASE:

18M - well-defined areas of hair loss with broken hair shafts

  1. Diagnosis?
  2. Mx?
    BONUS: what to order on blood test before starting the Mx?
A
  1. Tinea capitis
  2. Mx = systemic antifungals (e.g. terbinafine) + anti-fungal shampoos to reduce transmission

BONUS: order LFTs before starting terbinafine as it is metabolised in the liver

171
Q

DISEASE:

20M - rash on back after holiday in humid country (+ didn’t shower)
Scaly hypopigmented areas
Asymptomatic
Under Wood’s Lamp = faint orange fluorescence

  1. Diagnosis?
  2. Mx?
A
  1. Pityriasis versicolor (AKA tinea versicolor) = malassezia furfur
  2. Topical antifungal e.g. ketoconazole
172
Q

DISEASE:

35M - HIV-positive patient has odynophagia
White, ‘cottage cheese’ patches in the mouth

  1. Diagnosis?
  2. Ix?
  3. Mx?
A
  1. Candidiasis = candida albicans
  2. Ix = Germ tube test (for albicans)
  3. Mx = fluconazole
173
Q

DISEASE:

46M - neck stiffness, fever, and photophobia
PMHx = HIV, poor compliance to medications

LP + India ink stain = CSF positive for yeast cells w/ a gelatinous capsule and a positive halo sign

  1. Diagnosis?
  2. Mx?
A
  1. Cryptococcus neoformans
  2. Amphotericin B
174
Q

DISEASE:

50M - farmer presents with chronic cough + chest pain + fever
He resides near the Mississippi River

  1. Diagnosis?
  2. Vector?
A
  1. Histoplasmosis = Histoplasma capsulatum
  2. Found in bird/bat droppings → causes chronic progressive lung disease; endemic to Mississippi river
175
Q

DISEASE:

What fungal antigen may be detected in blood samples in a patient with invasive aspergillosis?

A

Galactomannan

176
Q

DISEASE:

60M - severe haemoptysis
PMHx = COPD + poorly controlled HIV
CT scan = multiple large bullae + large left upper lobe rounded mass with surrounding air crescent Serum galactomannan = positive

  1. Diagnosis?
  2. Increase in risk of which type of cancer?
A
  1. Aspergilloma = aspergillus
  2. If aspergillus flavus → produces aflatoxin that can lead to hepatocellular carcinoma (HCC)
177
Q

DISEASE:

65F - black pus from the nose + severe facial cellulitis on the jaw
PMHx = diabetes
O/E = necrotic lesions around the face

  1. Diagnosis?
  2. Mx?
A
  1. Mucormycosis = rhizopus and mucor
  2. Surgical debridement (+ amphotericin B)
178
Q

DISEASE:

45F - thickened nails on her hands and feet

Diagnosis?

A

Onychomycosis

179
Q

DISEASE:

40F - gardener
Painless nodular lesions on arm following rose prick injury

Diagnosis?

A

Sporotrichosis = sporothrix schnekenii

NOTE: may also present with ascending lymphadenopathy

180
Q

SUMMARY CARD:

What is the mechanism of action (+/- adverse effects) of the following anti-fungal medications:

  1. -azoles
  2. Amphotericin B (polyene)
  3. Terbinafine
  4. Griseofulvin
  5. Flucytosine
  6. Caspofungin
  7. Nystatin
A

1. -azoles

  • Targets cell membrane synthesis → inhibits 14α-demethylase which produces ergosterol
  • AEs = P450 inhibition, liver toxicity
  • Indications = yeast

2. Amphotericin B (polyene)

  • Targets cell membrane integrity → binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+ and Cl) leakage
  • AEs = nephrotoxicity, flu-like symptoms, hypokalaemia, hypomagnaseamia
  • Indications = systemic fungal infections e.g. cryptococcus, aspergilloma

3. Terbinafine

  • Targets cell membranes → inhibits squalene epoxidase
  • Indications = oral form used to treat nail infections

4. Griseofulvin

  • Interacts w/ microtubules to disrupt mitotic spindle
  • AEs = induces P450 system, teratogenic

5. Flucytosine

  • Inhibits DNA synthesis → converted by cytosine deaminase to 5-fluorouracil, which inhibits thymidylate synthase and disrupts fungal protein synthesis
  • AE = vomiting

6. Caspofungin (echinocandin)

  • Targets cell wall → inhibits synthesis of beta-glucan (fungal cell wall component)
  • AEs = flushing
  • Indications = yeast infections (less toxic SEs)

7. Nystatin

  • Targets cell membrane integrity → binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+ and Cl) leakage
  • Due to toxicity, can only be used topically (e.g. for oral thrush)
181
Q

SUMMARY CARD:

What are the causative organisms of the following congenital infections:

  1. Toxoplasmosis
  2. Neonatorum opthalmia
  3. Parvovirus
  4. Varicella Zoster Virus
  5. Rubella
  6. Cytomegalovirus
  7. Herpes Simplex Virus
  8. HIV
  9. Syphilis
  10. Congenital zika

TORCH (Toxoplasmosis, Other (HIV, HBV), Rubella, CMV, HSV)

A
  1. Toxoplasmosis → toxoplasma gondii
  2. Neonatorum opthalmia → chlamydia trachomatis / neisseria gonorrhoeae
  3. Parvovirus → parvovirus B19
  4. Varicella Zoster Virus → VZV (HHV3 is the most common VZV)
  5. Rubella → Rubella
  6. Cytomegalovirus → CMV (HHV5 is the most common CMV)
  7. Herpes Simplex Virus → HSV
  8. HIV → HIV
  9. Syphilis → treponema pallidum
  10. Congenital Zika → zika virus
182
Q

SUMMARY CARD:

  • What are the features of congenital toxoplasmosis?
  • How is it diagnosed +/- managed?
A
  • Toxoplasma gondii
  • 60% asymptomatic at birth (but later develop low IQ + deafness)
  • 40% symptomatic → cerebral calcification triad = seizures, hydrocephalus, chorioretinitis (+ cataracts)
  • NOTE: Seize (seizures) High (hydrocephalus) Colours (chorioretinitis)
  • Mx = pyrimethamine
183
Q

SUMMARY CARD:

  • What are the features of neonatorum opthalmia?
  • How is it diagnosed +/- managed?
A
  • Chlamydia trachomatis / Neisseria gonorrhoeae
  • Newborn conjunctivitis → same-day ophthalmology assessment
184
Q

SUMMARY CARD:

  • What are the features of congenital parvovirus?
  • How is it diagnosed +/- managed?
A
  • Parvovirus B19
  • Can cross the placenta in pregnant women
  • Causes severe anaemia and consequent heart failure in the foetus, leading to hydrops fetalis (ascites, pleural +/- pericardial effusions)
  • Ix = maternal serology to check for IgM against parvovirus B19; PCR to detect parvovirus B19 DNA
  • Mx = regular monitoring for complications
185
Q

SUMMARY CARD:

  • What are the features of congenital VZV?
  • How is it diagnosed +/- managed?
A
  • Varicella Zoster Virus (most common = human herpes virus 3)
  • Congenital varicella syndrome only occurs if mother infected within 20 weeks gestation
  • Infections Can Cause Many Lifelong Complications
  • IUGR (Intrauterine Growth Restriction)
  • Cataracts
  • Chorioretinitis
  • Microcephaly
  • Limb hypoplasia
  • Cutaneous scarring
  • NOTE: maternal infection during time of delivery can lead to severe, disseminated infection in the newborn
  • Mx = check maternal IgG antibody to varicella zoster → if negative, oral aciclovir
186
Q

SUMMARY CARD:

  • What are the features of congenital rubella?
  • How is it diagnosed +/- managed?
A
  • Rubella virus
  • RARE due to MMR vaccine
  • Triad = cataracts, patent ductus arteriosus, sensorineural deafness
  • NOTE: mnemonic for triad = Child Protective Services
  • Most common in first trimester, low risk after 20 weeks
  • Ix = maternal IgM + IgG serology; PCR for rubella virus RNA
  • Mx = supportive
187
Q

SUMMARY CARD:

  • What are the features of congenital CMV?
  • How is it diagnosed +/- managed?

hoot hoot

A
  • Cytomegalovirus (human herpes virus 5 = most common)
  • Great Mothers Protect Every Half Sibling
  • Growth retardation
  • Microcephaly
  • Pinpoint petechial ‘blueberry muffin’ skin lesions
  • Encephalitis (seizures)
  • Hepatosplenomegaly
  • Sensorineural deafness
  • NOTE: complications in the baby are uncommon if infection occurs beyond 20 weeks’ gestation
  • Histology = “Owl’s eye” appearance → intranuclear inclusion bodies
  • Mx = ganciclovir
188
Q

SUMMARY CARD:

  • What are the features of congenital HSV?
  • How is it diagnosed +/- managed?
A
  • Herpes simplex virus
  • Most likely transmitted to neonate in the third trimester
  • 3 forms of neonatal herpes simplex infection:
  • Localised to SEM (skin, eye, and mouth) disease causing a blistering rash
  • Localised to CNS causing meningoencephalitis
  • Disseminated infection casuing multiple organ involvement
  • Mx = IV aciclovir
189
Q

SUMMARY CARD:

  • What are the features of congenital HIV?
  • How is it diagnosed +/- managed?
A
  • Human immunodeficiency virus
  • ↑ risk of intrauterine transmission from HIV-positive mother to child
  • Newborn with HIV = failure to thrive, developmental delay, recurrent / opportunistic infections, progressive encephalopathy
  • Mx = ART (zidovudine) for mother to get viral load < 50 HIV RNA copies/mL at 36 weeks’ gestation; neonatal ART prophylaxis should be commenced within 4 hours after birth + given for 4 weeks
  • NOTE: maternal viral load is the most predictive factor for perinatal HIV transmission
190
Q

SUMMARY CARD:

  • What are the features of congenital syphilis?
  • How is it diagnosed +/- managed?
A
  • Treponema pallidum
  • Mnemonic: Syphilis Really Has Ugly Hidden Markers
  • Saddle-rash deformity
  • Rash on hands and soles
  • Hepatosplenomegaly
  • Unilateral enlargement of clavicle
  • Hutchinson’s teeth
  • Mulberry molars
  • Ix = syphilis screening assay
191
Q

SUMMARY CARD:

  • What are the features of congenital zika virus?
  • How is it diagnosed +/- managed?
A
  • Zika virus (enveloped flavivirus)
  • Severe microcephaly + skull deformity
  • Secreased brain tissue, subcortical calcification
  • Retinopathy + deafness
  • Talipes (feet turned in like club foot)
  • Hypertonia
192
Q

SUMMARY CARD:

What are the causes of early vs. late onset neontal sepsis?

A

Neonatal = < 6 weeks old

Early onset sepsis = < 48hrs after birth

  • Pathogens = Group B streptococcus, E. coli, Listeria monocytogenes
  • Maternal Sx = (P)PROM, fever, foetal distress
  • Neonatal Sx = respiratory distress, acidosis, fever, clinically unwell
  • Ix = SEPTIC SCREEN (FBC, CRP, blood culture, ABG, urinalysis, LP, CXR)
  • Mx = Benzyl penicillin + gentamicin + amoxicillin/ampicillin (for listeria cover)

Late onset sepsis = > 48hrs after birth

  • Pathogens = Coagulase -ve staph (e.g. epidermidis, haemolyticus, saphrophyticus), Group B streptococcus, E. coli, Listeria monocytogenes
  • Neonatal Sx = bradycardia, apnoea, poor feeding, irritability
  • Ix = SEPTIC SCREEN (FBC, CRP, blood culture, ABG, urinalysis, LP, CXR)
  • Mx = benzylpenicillin + gentamicin (2nd line: Tazocin + vancomycin)
  • Mx for late onset from community = amoxicillin + cefotaxime
193
Q

SUMMARY CARD:

Most common causative organisms of bacterial meningitis in:

  1. > 3 months of age
  2. < 2 years old
  3. < 3 months old + unvaccinated
  4. 1-3 months old
A
  1. > 3 months of age = neisseria meningitidies (non-blanching petechial rash AKA meningococcal septicicaemia)
  2. < 2 years old = streptococcus pneumoniae
  3. < 3 months old + unvaccinated = haemophilus influenzae
  4. 1-3 months old = GBS / E.coli / listeria
194
Q

DISEASE:

What is the triad of symptoms caused by toxoplasmosis?

seize high colours

A

TRIAD = seizures, hydrocephalus, chorioretinitis

Mnemonic = Seize (seizures) High (hydrocephalus) Colours (chorioretinitis)

(still waiting for a better one sigh)

195
Q

DISEASE:

Newborn - bilateral purulent eye discharge
Born to a mother with no prenatal care or STI screening
Vaginal delivery

  • Likely causative pathogen?
A

Neisseria gonorrhoea or chlamydia trachomatis

196
Q

DISEASE:

What condition is a foetus at risk of if its mother is infected by Parvovirus B19?

A

Hydrops fetalis (effusions + ascites)

197
Q

DISEASE:

What are the features of congenital VZV?

Infections Can Cause Many Lifelong Complications

A

Infections Can Cause Many Lifelong Complications

  • IUGR (Intrauterine Growth Restriction)
  • Cataracts
  • Chorioretinitis
  • Microcephaly
  • Limb hypoplasia
  • Cutaneous scarring
198
Q

DISEASE:

What is the triad of Sx in congenital rubella?

child protective services

A

Child Protective Services

  • Cataracts
  • PDA (patent ductus arteriosus)
  • Sensorineural deafness
199
Q

DISEASE:

Newborn - bilateral cataracts + retinopathy
Heart murmur (continuous, “machinery” murmur below the clavicle)
Bilateral hearing loss on otoacoustic emission test
Abdominal mass
Mother has no known past medical history

  • Likely viral exposure during pregnancy?
A

Rubella

200
Q

DISEASE:

2 wk old neonate - microcephaly + petechial rash + hepatosplenomegaly
Peripheral blood leukocytes reveals intranuclear inclusion bodies

  • What congenital virus is the most likely cause of these findings?
A

Cytomegalovirus (CMV)

NOTE: Great Mothers Protect Every Half Sibling
* Growth retardation
* Microcephaly
* Pinpoint petechial ‘blueberry muffin’ skin lesions
* Encephalitis (seizures)
* Hepatosplenomegaly
* Sensorineural deafness
* Histology = “Owl’s eye” appearance → intranuclear inclusion bodies

201
Q

DISEASE:

Rash on baby’s face

The examination notes made by the neonatologist: ‘10-hour old baby. Widespread vesicles and pustules on face, lips involved. Eyes not involved. Salmon patch on left eyelid. Milia on nose. No other abnormalities. Obs reviewed and normal.’

  • What is the most likely causative organism?
A

Neonatal herpes simplex infection - characterised by vesicles and pustules involving the face + mouth

Neonatal herpes simplex infection can manifest in 3 forms: localised to the skin, eyes and mouth (SEM), localised to the central nervous system (i.e. encephalitis) and disseminated infection.

202
Q

DISEASE:

What is the tooth deformity in congenital syphilis?

A

Hutchinson’s teeth
Mulberry molars

203
Q

DISEASE:

Newborn - rash on the hands + soles, saddle-rash deformity, + hepatosplenomegaly
O/E = unilateral enlargement of the clavicle

  • Which congenital infection?
A

Syphilis

204
Q

DISEASE:

28F - antenatal scan at 32 weeks
Recent travel to South America
USS shows: foetal microcephaly + skull deformity w/ intracranial calcifications + club feet

  • What is the most likely congenital infection?
A

Zika virus

205
Q

SUMMARY CARD:

What are some examples of viruses in:

  1. Herpesviridae (cause latent infections)
  2. Polyomaviridae
  3. Respiratory viruses
  4. Hepatitis viruses

BONUS: how do viral infections affect the immunocompromised differently?

A
  1. Herpesviridae (may cause latent infections): CMV, EBV, HSV, HHV6, HHV8, VZV
  2. Polyomaviridae: JC (John Cunningham) virus (leads to PML if given mycophenolate mofetil) + BK (Human polyomavirus 1) virus
  3. Respiratory viruses: influenza A + B, parainfluenzae, Respiratory
    Syncytial Virus (RSV), adenovirus, coronavirus
  4. Hepatitis viruses: A (normally vaccinate prior to immunosuppression), B, C, D, E

BONUS: 4 D's = Dissemination, Different organs, Disastrous severity, Dysplasia

206
Q

SUMMARY CARD:

Virology basics:

  • All DNA viruses are double stranded EXCEPT…
  • All RNA viruses are single stranded EXCEPT…
A
  • Parvovirus = DNA virus that is single stranded
  • Reoviridae (e.g. rotavius) = RNA virus that is double stranded

NOTE: RNA viruses can be +ve sense or -ve sense → +ve sense means the RNA can be directly translated, whereas -ve sense means the RNA cannot be directly translated

207
Q

SUMMARY CARD:

What are some features of the following herpesviridae:

  1. CMV
  2. EBV
  3. HSV
  4. HHV6
  5. HHV8
  6. VZV
A

1. CMV

  • Enveloped, dsDNA genome
  • Lies latent in monocytes + dendritic cells
  • CMV cells = “owls eye” (inclusion bodies)
  • Sx in immunocompromised (affects esp. transplant patients) = encephalitis, retinitis, pneumonitis, colitis, marrow suppression, oesophagitis (LINEAR ulcers)
  • Mx = IV Ganciclovir / PO valganciclovir (1st line); IV Foscarnet (2nd line)

2. EBV

  • Enveloped, dsDNA genome
  • Lies latent in B cells
  • NOTE: EBV not dangerous in pregnancy!
  • Glandular fever = TRIAD of fever, pharyngitis, lymphadenopathy
  • Ix = blood film (atypical lymphocytes peripherally - stretched out cytoplasm), EBV serology
  • Monospot agglutination (AKA heterophile antibody test AKA Paul-Bennell test) = diagnostic
  • Mx = supportive
  • Mx w/ penicillins in glandular fever may provoke a morbilliform eruption (widespread maculopapular rash)
  • As EBV can lie dormant in B-cells, it predisposes to Burkitt’s lymphoma
  • Post-transplant Lymphoproliferative Disease (PTLD) in immunocompromised Patients → Mx w/ Rituximab (anti-CD20 monoclonal Ab)
  • Mnemonic: BBB → EBV, resides in B cells, predisposes to Burkitt’s lymphoma

3. HSV

  • Enveloped, dsDNA genome
  • Lies latent in sensory neurons
  • HSV-1 → herpes labialis (cold sores) = severe painful ulceration, erythematous base +/- fever + submandibular lymphadenopathy
  • Differential – Herpangina (Coxsackie A)
  • HSV-2 → genital ulceration = fever, dysuria, malaise, Inguinal lymphadenopathy, pain, + vesicular rash
  • HSV-2 may cause sacral radiculomyelitis → urinary retention (self limiting)
  • NOTE: HSV-1 more likely to cause encephalitis, whereas HSV2 is more likely to cause meningitis
  • Sx in immunocompromised: cutaneous dissemination, oesophagitis causing odynophagia (CIRCULAR ulcers), hepatitis, viraemia, herpetic whitlow (HSV skin infection)
  • Mx = aciclovir (or valaciclovir, ‘val’ meaning ucreased bioavailability to take orally)

4. HHV6

  • AKA roseola virus
  • Latent in monocytes / lymphocytes
  • Roseola infantum ( = exanthum subitum, Sixth disease) → FEVER then sudden appearance of a maculopapular rash (starts on trunk + spreads to face / extremities)
  • Most common cause of febrile convulsions
  • Transmits via droplet infection
  • Supportive Mx

5. HHV8

  • AKA Kaposi’s sarcoma
  • Enveloped, dsDNA genome
  • Genital transmission
  • Kaposi’s sarcoma seen in immunocompromised, esp. due to HIV
  • Mx = chemoradiotherapy + surgical excision + HAART for underlying HIV
  • If HHV8 associated with EBV co-infection → primary effusion lymphoma

6. VZV

  • Enveloped, dsDNA genome
  • Lies latent in sensory neurons; hence dermatomal distribution when it is reactivated
  • Chickenpox Sx = fever + headache followed by itchy rash
  • Eye involvement = opthalmic herpes zoster
  • Facial palsy (unilateral facial drooping) + vesicles in ear = Ramsay hunt syndrome
  • Shingles (reactivation) RFs = older, stress, ↓ immunity
  • Shingles Sx = painful rash in specific dermatome
  • In immunocompromised, more likely to cause retinal necrosis + multidermatomal shingles
  • Mx w/ aciclovir if adult / immunocompromised neonate / eye involvement
208
Q

SUMMARY CARD:

What are some features of the following polyomaviridae:

  1. JC (John Cunningham) virus
  2. BK (Human polyomavirus 1) virus
A

1. JC (John Cunningham) virus

  • Unenveloped, dsDNA genome
  • In immunocompromised (especially AIDS): Progressive multifocal leukoencephalopathy (PML)
    + rapidly demyelinating disease (+ neurological deficits)
  • Mx = HAART for HIV

2. BK (Human polyomavirus 1) virus

  • Unenveloped, dsDNA genome
  • In immunocompromised (esp. transplant): BK haemorrhagic cystitis + BK nephropathy (as it lies dormant in kidneys)
  • Mx = Cidofovir
209
Q

SUMMARY CARD:

What are some features of the following respiratory viruses:

  1. Influenzae virus
  2. Adenovirus
  3. Coronavirus
A

1. Influenzae virus

  • Enveloped, negative sense segmented genome (8 segments)
  • Antigenic DRIFT = point mutations
  • Antigenic SHIFT = segments rearrange (can cause pandemics)
  • Sx = URTI + systemic features include muscle aches
  • Haemagglutinin activity = binds to sialic receptors + allows for virus ENTRY
  • Neuraminidase activity = cleaves sialic acid + allows for EXIT of virions from host cell
  • Mx = oral oseltamivir (neuraminidase inhibitor) - AKA Tamiflu
  • Other Mx = polymerase inhibitor (e.g. Baloxavir)

2. Adenovirus

  • Unenveloped, dsDNA genome
  • In immunocompromised (especially transplant): encephalitis, pneumonitis, colitis, haemorrhagic cystitis
  • Supportive Mx, unless multi-organ involvement, then Cidofovir +/- IVIG

3. Coronavirus

  • Positive sense ssRNA genomes
  • URTI +/- systemic symptoms e.g. myalgia
  • Severe infections can cause ARDS, respiratory failure, shock, multiple organ dysfunction
  • Mx = supportive OR dexamethasone + remdesivir if severe
210
Q

SUMMARY CARD:

What are some features of the following hepatides:

  1. Hepatitis A
  2. Hepatitis B
  3. Hepatitis C
  4. Hepatitis D
  5. Hepatitis E
A

1. Hepatitis A

  • Unenveloped picornavirus, positive sense ssRNA genome
  • Acute infection
  • Faeco-oral transmission
  • Acute hepatitis = 2-6 weeks incubation, severe in elderly
  • Ix = anti-HAV IgM in acute infection (IgM persists up to 14wks)
  • Mx = supportive; Hep A vaccine available

2. Hepatitis B

  • Enveloped hepadnavirus (reversivirus); hybrid
    genome, mostly DNA
  • Transmission via bodily fluids i.e. sexual, vertical, blood products
  • Acute (90% resolve in >5 y/o) or chronic
  • HBV at risk of reactivation in immunocompromised e.g. Rituximab
  • HBV serology
  • HbsAg (surface antigen) = present in acute or chronic infection, but negative in previous or vaccinated
  • Anti-HBs (hep B surface antibody) = negative in acute or chronic infection, but positive in previous or vaccinated
  • NOTE: vaccine does NOT have core antigen!
  • So to differentiate between vaccine vs previous infection → vaccine does not have anti-HBc IgG but if previously infected, you would
  • To differentiate between acute vs chronic infection → anti-HBc IgM in acute and anti-HBc IgG in chronic
  • HBe = infectivity
  • Mx = interferon alpha, lamivudine (nucleoside analogue), entecavir (nucleoside analogue), telbivudine (nucleoside analogue), tenofovir (nucleoTide analogue)

3. Hepatitis C

  • Enveloped flavivirus, positive sense ssRNA genome
  • Mainly a chronic disease (acute less common) - hep C for Chronic
  • Blood borne = infected needles, blood transfusions etc.
  • Complications = cirrhosis, cryoglobulinaemia, glomerulonephritis
  • Measure HCV RNA to confirm infection and assess treatment response (anti-HCV Ab develops after acute infection)
  • Mx = Peg INF alpha
  • Curative Mx = NS3/4 protease inhibitors (-previrs, block translation e.g. telaprevir, boceprevir) + NS5A inhibitors (-asvirs, block release e.g. ledipasvir, daclatasvir) + direct polymerase inhibitors (-buvirs,
    block replication e.g. sofosbuvir, dasabuvir)

4. Hepatitis D

  • Deltavirus, enveloped virus, negative sense,
    single-stranded circular RNA
  • Can only infect those with Hep B
  • Transmission = sexual, perinatal
  • May be a coinfection (simultaneously) with Hep B OR superinfection (on top of chronic) Hep B (more severe – often leads to cirrhosis within 2-3yrs)
  • Mx = Peg INF alpha

5. Hepatitis E

  • Unenveloped positive sense ssRNA genome
  • Acute infection
  • Faeco-oral transmission
  • RFs = India
  • Rare complications: CNS disease e.g. Bell’s palsy, Guillain Barre, other neuropathy
  • Mx = supportive
211
Q

SUMMARY CARD:

What are the susceptible infections in HIV based on CD4+ count:

  1. CD4+ < 500
  2. CD4+ < 200 (NOTE: this is considered AIDS)
  3. CD4+ < 100
A

1. CD4+ < 500

  • EBV (hairy leukoplakia)
  • HHV-8 (Kaposi sarcoma)
  • HPV (SCC)
  • Candida (thrush)

2. CD4+ < 200 (NOTE: this is considered AIDS)

  • JC virus (reactivation = progressive multifocal leukoencephalopathy)
  • Pnuemocystitic jeroveci (pneumonia)
  • Histoplasma capsulatum (systemic Sx)

3. CD4+ < 100

  • Bartonella henselae (cat scratch disease)
  • Nontuberculous mycobacteria (lymphadenitis)
  • CMV (colitis, retinitis, oesophagitis)
  • Aspergillus (haemoptysis, pain, fever)
  • Candida (oesophagitis)
  • Cryptococcus neoformans (meningitis)
  • Cryptosporidium parvum (severe non-bloody darrhoea; Kinyoun acid fast stain)
  • Toxoplasma (brain abscess)
212
Q

SUMMARY CARD:

What are the susceptible infections in the following immunocompromised states:

  1. Cystic fibrosis
  2. Sickle cell disease
  3. Splenectomy
A

1. Cystic fibrosis

  • Aspergillus fumigatus
  • Burkholderia cepecia (CI for lung transplant)
  • Pseudomonas aeruginosa
  • Mycobacterium abscessus

2. Sickle cell disease

  • Salmonella typhi (osteomyelitis)

3. Splenectomy

  • NHS = neisseria meningitides, haemophilus influenzae, streptococcus pneumoniae
213
Q

SUMMARY CARD:

What are the following features of HIV:

  1. Structure
  2. Entry
  3. Sx / antibodies
  4. Management
A

1. HIV structure

  • 2 copies of a ssRNA genome within a conical capsid of p24 (which is surrounded by a matrix of viral protein p17)
  • Viral envelope contains glycoproteins gp120 and gp41
  • Pol gene encodes for reverse transcriptase, integrase and HIV protease

2. HIV entry

  • HIV can infect CD4 T cells, macrophages and dendritic cells
  • Gp120 binds to CD4 and CXCR4 on T cells and CD4 and CCR5 on macrophages
  • NOTE: mutations in CCR5 can give immunity to HIV

3. HIV Sx / antibodies

  • Sx = glandular fever-like illness
  • Ix = HIV antibodies using ELISA first, confirmed by Western Blot
  • p24 antigen positive from 1 week to 3-4 weeks after infection
  • Standard Ix for diagnosis = combination of antibodies + p24 antigen

4. Management

  • 2 NRTIs + 1 NNRTI / PI
  • Entry inhibitors e.g. maraviroc (binds to CCR5) or enfuvirtide (binds to gp41)
  • Nucleoside analogue reverse transcriptase inhibitor (NRTI) e.g. zidovudine (SE = anaemia), tenofovir (recommended NRTI)
  • NOTE: SEs of NRTIs = peripheral neuropathy, black nails
  • Non-nucleoside reverse transcriptase inhibitors (NNRTI) e.g. nevirapine (P450 enzyme inducer)
  • Protease inhibitors (-navir) e.g. ritonavir (potent inducer of P450 system)
  • Integrase inhibitors (-gravir) e.g. raltegravir (blocks integrase, the enzyme that inserts viral genome into DNA of host cell)
214
Q

DISEASE:

40M - purple papules + plaques on his skin and oral mucosa
PMHx = HIV-positive w/ poor compliance to HAART
Recent onset of cough and haemoptysis
CXR = pleural effusion

  • Which virus is most likely associated with his condition?
  • What is the appropriate management?
A

HHV-8 (Kaposi sarcoma) = a type of cancer that forms in the lining of blood vessels and lymph vessels

Sx = reddish purple skin lesions, in the lungs can cause SOB + haemoptysis

Mx = radiotherapy and resection

215
Q

DISEASE:

35M - progressively worsening blurred vision bilaterally
PMHx = HIV-positive w/ poor compliance to HAART
Fundoscopy = retinal hemorrhages and areas of necrosis resembling a “pizza” appearance

  • Diagnosis? (virus)
  • Mx?
A

CMV retinitis

Mx = IV ganciclovir (1st line)

216
Q

DISEASE:

Patient undergoing allogeneic stem cell transplantation requires a blood transfusion

All blood products are routinely screened for HIV, Hepatitis B and C

  • What other virus must be screened for in the donor blood products prior to giving it to this patient?
  • What Sx can this virus cause in the immunocompromised?
A

CMV

(affects esp. transplant patients)

Sx in immunocompromised = encephalitis, retinitis, pneumonitis, colitis, marrow suppression, oesophagitis (LINEAR ulcers)

217
Q

DISEASE:

Presence of atypical lymphoycytes on a peripheral blood film suggests what diagnosis?

A

EBV

Ix for EBV:
* Blood film = atypical lymphocytes peripherally - stretched out cytoplasm
* EBV serology
* Monospot agglutination (AKA heterophile antibody test AKA Paul-Bennell test) = diagnostic

218
Q

DISEASE:

What is the triad of Sx seen in EBV?

BONUS: what is the rash from penicillin reaction in EBV called?

BONUS 2: what cancer does EBV predispose in the immunocompromised?

A

TRIAD of fever + pharyngitis + lymphadenopathy

BONUS: morbilliform eruption (widespread maculopapular rash)

BONUS 2: As EBV can lie dormant in B-cells, it predisposes to Burkitt’s lymphoma

Mnemonic: BBB → EBV, resides in B cells, predisposes to Burkitt’s lymphoma

219
Q

DISEASE:

25F - new sexual partner
Painful genital ulceration, fever, dysuria, malaise, + inguinal lymphadenopathy
O/E - vesicular rash in the affected area

  • Which virus is most likely responsible for her symptoms?
  • What is the appropriate treatment?

BONUS: what type of oesophageal ulcers can it cause in the immunocompromised?

A

HSV-2 (causes genital ulcers)
Mx = aciclovir

BONUS: in the immunocompromised it can cause oesophagitis with CIRCULAR ulcers (unlike CMV which causes linear ulcers)

NOTE: HPV genital warts are usually painless, without ulceration

220
Q

DISEASE:

60F - painful, vesicular rash on the left forehead extending to the nose (following dermatomal distribution)
Fever, headache + reduced vision in her left eye

  1. Diagnosis (+ virus)?
  2. Mx?

BONUS: complications?

Ramsay hunt syndrome; opthalmic herpes zoster

A

Shingles (VZV)

Mx = aciclovir

Complications:

  • Eye involvement = opthalmic herpes zoster
  • Facial palsy (unilateral facial drooping) + vesicles in ear = Ramsay hunt syndrome
221
Q

DISEASE:

55M - progressive weakness in his limbs and difficulty walking
PMHx = HIV/AIDs
Brain MRI = multiple white matter lesions
LP + PCR = JC virus DNA

  • Diagnosis?
  • Mx?
A

Progressive multifocal leukoencephalopathy (PML)
no specific Mx for JC virus → supportive care + optimal HAART for HIV

222
Q

DISEASE:

Which organ does the BK virus primarily affect in the immunocompromised?

A

Lies dormant in the kidneys → BK nephropathy

Mx = Cidofovir

NOTE: BK virus = human polyomavirus

223
Q

DISEASE:

What is the medication given to treat influenza?

A

Oseltamivir (neuraminidase inhibitor)

224
Q

DISEASE:

Which hepatitis is chronic?
How is it spread?

A

Hepatitis C (for chronic)

Spread via infected blood e.g. sharing needles, blood transfusions

225
Q

DISEASE:

Interpret the following HBV serology:
HBsAg = +ve
Anti-HBs = -ve
Anti-HBc IgM = +ve
Anti-HBc IgG = -ve
Anti-HBe = +ve

A

Acute infection + high infectivity

HBsAg +ve = current infection
Anti-HBc IgM +ve and IgG -ve = acute infection
Anti-HBe +ve = high infectivity

226
Q

DISEASE:

Which are the acute Hepatides and how are they transmitted?

A 
Hep A + E
faeco-oral
227
Q

DISEASE:

What are some CNS complications of Hep E?

A

Bell’s palsy, Guillain Barre

228
Q

DISEASE:

Mutation in what can be protective against HIV?

A

Mutations in CCR5 can give immunity to HIV

NOTE: HIV infects macrophages via CCR5

229
Q

DISEASE:

  • Which gene in HIV codes for: reverse transcriptase, integrase and HIV protease?
  • How is HIV diagnosed?
A
  • Pol gene
  • ELISA Anti-HIV antibodies = screening (NB: unreliable in babies as IgGs maybe passed vertically)
  • Western Blot = confirmatory (15-45 days since infection)
  • Viral load using PCR = very sensitive
  • Flow cytometry for CD4 count (< 200 = AIDS)
  • ART resistance assays
230
Q

DISEASE:

How is HIV managed?

A
  • HAART = 3+ ART drugs needed
  • Usually: 2 NRTIs + 1x NNRTI OR boosted PI
  • Indications for immediate HAART = SYMPTOMATIC, CD4+ < 200 cells/ul, consider if CD4 between 200 and 350

Nucleoside reverse transcriptase inhibitors (NRTI) e.g. Zidovudine/Abacavir (OR nucleotide RTI e.g. tenofovir)
NNRTI e.g. efavirenz
Boosted PI e.g. ritonavir
2nd line = integrase inhibitors (-gravir)
2nd line = entry / attachment inhibitors (e.g. maraviroc)
2nd line = fusion inhibitors (e.g. enfuvirtide)

231
Q

DISEASE:

Niche:
Pt on HAART for HIV taking abacavir (NRTI) + tenofovir (NRTI) + efavirenz (NNRTI)
HOWEVER, their HTN is poorly managed on amlodipine

WHY?

A

Due to efavirenz being a P450 inducer

232
Q

SUMMARY CARD:

What is the MOA (+ AEs) of the following anti-virals:

  1. Aciclovir
  2. Ganciclovir
  3. Ribavirin
  4. Amantadine
  5. Oseltamivir
  6. Foscarnet
  7. Interferon-α
  8. Cidofovir
A

1. Aciclovir

  • Guanosine analogue, phosphorylated by thymidine kinase
  • Inhibits the viral DNA polymerase
  • Used to Mx HSV, VZV
  • AE = crystalline nephropathy

2. Ganciclovir

  • Guanosine analogue, phosphorylated by thymidine kinase
    Inhibits the viral DNA polymerase
  • Used to Tx CMV
  • AE = myelosuppression / agranulocytosis

3. Ribavirin

  • Guanosine analogue that inhibits inosine monophosphate (IMP) dehydrogenase → interferes with the capping of viral mRNA
  • Used to Tx chronic hepatitis C, RSV
  • AE = haemolytic anaemia

4. Amantadine

  • Inhibits uncoating (M2 protein) of virus in cells
  • Also releases dopamine from nerve endings
  • Used to Tx Parkinson’s, influenza
  • AEs = confusion, ataxia, slurred speech

5. Oseltamivir

  • Inhibits neuraminidase
  • Used to Tx Influenza

6. Foscarnet

  • Pyrophosphate analogue which inhibits viral DNA polymerase
  • Used to Tx CMV, HSV if not responding to aciclovir
  • AEs = nephrotoxicity, hypocalcaemia, hypomagnasaemia, seizures

7. Interferon-α

  • Human glycoproteins that inhibit synthesis of mRNA
  • Used to Tx chronic hepatitis B & C, hairy cell leukaemia
  • AEs = flu-like symptoms, anorexia, myelosuppression

8. Cidofovir

  • Acyclic nucleoside phosphonate
  • NOTE: it is therefore independent of phosphorylation by viral enzymes (compare and contrast with aciclovir/ganciclovir)
  • Used to Tx CMV retinitis in HIV
  • AE = nephrotoxicity
233
Q

DISEASE:

25F - painful vesicular rash on her lip
She has had similar episodes in the past
?recurrent herpes simplex infection

  • Most appropriate antiviral Mx?
A

Aciclovir

234
Q

DISEASE:

30M - HIV-positive patient
Diagnosed with cytomegalovirus (CMV) retinitis

  • Most appropriate antiviral Mx?
A

Cidofovir (or ganciclovir)

235
Q

SUMMARY CARD:

How can gram +ve pathogens be split?

What are some gram +ve pathogens?

HINT: into cocci + rods

A
  1. Cocci

Catalase +ve = staphylococcus

  • Co-agulase +ve = staphylococcus aureus
  • Co-agulase -ve = staphylococcus saprophyticus, epidermidis

Catalase -ve = streptococcus → blood agar

  • Alpha haemolytic (PARTIAL haemolysis - green agar) = streptococcus pneumoniae (optochin sensitive), streptococcus viridans (optochin resistant)
  • Beta haemolytic (COMPLETE haemolysis) = streptococcis pyogenes (GAS, bactracin sensitive), streptococcus agalactaei (GBS, bacitracin resistant)
  • Gamma haemolytic (NO haemolysis) = enterococcus
  1. Rods
  • Actinomyles
  • Bacillus cereus
  • Clostridium
  • Diphtheria
  • Listeria monocytogenes
236
Q

SUMMARY CARD:

How can gram -ve pathogens be split?

What are some gram -ve pathogens?

macConkey agar / blood agar

A

Growth on MacConkey Agar = YES

Lactose fermenter on MacConkey Agar

  • Indole test +ve = Escherichia coli
  • Indole test -ve = Klebsiella pneumoniae

Non-Lactose fermenter on MacConkey Agar

  • Oxidase +ve = pseudomonas, vibrio
  • Oxidase -ve = salmonella, shigella, yersinia, proteus mirabilis

Growth on MacConkey Agar = NO

  • Growth on Blood Agar = brucella, eikenella (human bite), pasteurella (dog bite)
  • No growth on Blood Agar = haemophilus
237
Q

SUMMARY CARD:

Another gram -ve bacteria diagram:

A

Cocci:

  • Neisseria meningitides, gonorrhoea
  • Moraxella cararrhalis

Coccobacilli:

  • Haemophilus influenzae, ducreyi
  • Bordetella pertussis
  • Pseudomonas aeruginosa
  • Chlamydia trochamatis

Rods:

  • Enterobacteriacaea
  • Escherichia coli
  • Salmonella
  • Shigella
  • Klabsiella
  • Yersinia

Spirochaetes:

  • Treponema pallidum
  • Leptospirosis
  • Borrelia
238
Q

SUMMARY CARD:

What are some obligate intracellular microbes?

bacteria; protozoa; fungi

A

Bacteria:

  • Chlamydia trochamatis
  • Rickettsia
  • Coxiella (Q fever)
  • Mycobacteria laprae

Protozoa:

  • Toxoplasma
  • Cryptosporidium
  • Leishmania

Fungi:

  • Pneumocystitis jeroveci
239
Q

SUMMARY CARD:

Summary of the antibiotics and what pathogens they cover:

A
240
Q

SUMMARY CARD:

What is the MOA (+ indications + SEs) of the following beta-lactam antibiotics:

  1. Penicillins (-cillin)
  2. Carbapenems (-penem)
  3. Cephalosporins
A

1. Penicillins (-cillin)

  • E.g. amoxicillin, piperacillin (against pseudomonas)
  • Broad spectrum
  • Inhibits transpeptidase, the enzyme that forms crosslinks during cell wall formation
  • Indications = pneumonia, acute otitis media, susceptible infections
  • SEs = GI (e.g. diarrhoea/vomiting), Morbiliform rash (if given in EBV)

2. Carbapenems (-penem)

  • E.g. ertapenem, meropenem
  • Broad spectrum
  • Inhibits transpeptidase, the enzyme that forms crosslinks during cell wall formation
  • Indications = HAIs
  • SEs = injection site reactions, GI ( e.g. diarrhoea/vomiting)

3. Cephalosporins

  • E.g. ceftriaxone, cefalexin
  • Broad spectrum
  • Inhibits transpeptidase, the enzyme that forms crosslinks during cell wall formation
  • Indications = meningitis
  • SEs = Low toxicity but GI disturbances common
241
Q

SUMMARY CARD:

What is the MOA (+ indications + SEs) of the following TAMCO antibiotics:

  1. Tetracyclines (-cycline)
  2. Aminoglycosides
  3. Macrolides (-mycin)
  4. Chloramphenicol
  5. Oxazolidinones (-zolid)

TA= 30S, MC = 50S, O = 23S of 50S

A
  1. Tetracyclines (-cycline)
  • E.g. doxycycline, lymecycline
  • Broad spectrum
  • Bind to the 30S subunit of ribosomes
  • Indications = mycoplasma, rosacea, acne, lyme disease
  • AEs = Teratogenic + light-sensitive rash, contraindicated in < 12 y/o due to teeth discolouration
  1. A**minoglycosides **
  • E.g. gentamicin, amikacin
  • Gram -ve and/or anaerobes
  • Bind to 30S ribosomal subunit, preventing elongation of polypeptide chain
  • Indications = meningitis, endocarditis, acute pyelonephritis, catheter-associated UTI
  • SEs = ototoxic + nephrotoxic
  1. Macrolides (-mycin)
  • E.g. azithromycin, clarithromycin
  • Gram -ve
  • Bind to the 50S subunit of ribosomes
  • Indications = mild staph/strep infection if allergic to penicillin, specifically useful against Campylobacter + Legionella
  • SEs = nausea (especially erythromycin), P450 inhibitor, prolonged QT interval
  1. Chloramphenicol
  • Potent broad-spectrum antibiotic
  • Indications = conjunctivitis, plague (Causes dry gangrene slowly)
  1. Oxazolidinones (-zolid)
  • E.g. Linezolid
  • Binds to the 23S portion of the 50S ribosome subunit to prevent 70S subunit formation
  • Indications = highly active against gram +ve organisms - especially MRSA and VRE
  • SEs = thrombocytopaenia + neurological side effects
242
Q

SUMMARY CARD:

What is the MOA (+ indications + SEs) of the following antibiotics:

  1. Glycopeptide
  2. Nitroimidazoles (-dazole)
  3. Fluoroquinolone (-floxacin)
  4. Sulfonamides (-xazole)
A

1. Glycopeptide

  • E.g. vancomycin, teicoplanin
  • Gram +ve
  • inhibits cell wall formation by binding to D-Ala-D-Ala moieties, preventing polymerisation of peptidoglycans
  • Indications = MRSA infection
  • SEs = Nephrotoxic; Red man syndrome (on rapid infusion)

2. Nitroimidazoles (-dazole)

  • E.g. metronidazole, tinidazole
  • Anaerobes + Protozoa
  • Under anaerobic conditions, an active intermediate is produced which causes DNA strand breakage
  • Indication = anaerobic infections, H.pylori eradication, BV / TV, PID
  • SEs = dry mouth, myalgia and nausea; disulfiram reaction w/alcohol

3. Fluoroquinolone (-floxacin)

  • E.g. levofloxacin, ciprofloxacin
  • Broad spectrum
  • Act on alpha subunit of DNA gyrase
  • Indication = UTI, pneumonia, bacterial gastroenteritis, neutropenic sepsis prophylaxis
  • SEs = GI disturbances (C.difficile infection), CNS disturbances

4. Sulfonamides (-xazole)

  • Sulfamethoxazole (component of co-trimoxazole)
  • Broad spectrum
  • Inhibiting dihydropteroate synthetase
  • Indications = pneumocystis jirovecii (co-trimoxazole)
  • SEs = hyperkalaemia, headache, SJS rash
243
Q

DISEASE:

What are the MOAs for TAMCO?

A
  1. Tetracyclines (-cycline) = 30S
  2. Aminoglycosides = 30S
  3. Macrolides (-mycin) = 50S
  4. Chloramphenicol = 50S
  5. Oxazolidinones (-zolid) = 23S + 50S → 70S
244
Q

DISEASE:

22F - sore throat, fever, and difficulty swallowing
Dx = streptococcal pharyngitis

  • Which abx is most appropriate?
A

Penicillins e.g. amoxicillin

245
Q

DISEASE:

45M - Admitted to the hospital with sepsis
Causative organism = MRSA

  • Which abx is most appropriate?
A

Vancomycin

246
Q

DISEASE:

30F - UTI caused by pseudomonas aeruginosa

  • Which abx is most appropriate?
A

Piperacillin (+ tazobactam)

247
Q

DISEASE:

28M - returned from hiking trip
Sx = fever, headache, bull’s eye rash
Dx = Lyme disease

  • Which abx is most approrpiate?
A

Doxycycline

248
Q

DISEASE:

35F - lower abdominal pain + foul-smelling vaginal discharge
Microscopy - flagellated protozoa

  • Which abx is most appropriate?
A

Metronidazole (Dx = TV)

249
Q

SUMMARY CARD:

What is the typical organism + abx used at each of the following sites:

  1. Skin
  2. Pharyngitis
  3. CAP
  4. HAP
  5. Bacterial meningitis
  6. UTI
  7. Sepsis
  8. Colitis
A
  1. Skin → S. aureus → flucloxacillin
  2. Pharyngitis → beta-haemolytic strep → benzylpenicillin
  3. CAP → mild = amoxicillin; moderate = amoxicllin + clarithromycin
  4. H**AP → severe = co-amoxiclav + clarithromycin
  5. Bacterial meningitis → meningococcus / streptococcus → Ceftriaxone (+ amox/ampicillin for young/old for listeria cover)
  6. UTI → community → trimethoprim / nitrofurantoin (if HAI = co-amoxiclav or cephalexin)
  7. Sepsis → severe → tazocin / ceftriaxone, metronidazole + gentamicin (if neutropenic then tazocin + gentamicin)
  8. Colitis → C. diff → metronidazole or vancomycin
250
Q

SUMMARY CARD:

What microbes are the following stains used to detect?

  1. Giemsa
  2. India ink
  3. Periodic acid-Schiff stain
  4. Silver stain
  5. Ziehl-Neelsen
  6. Auramine-Rhodamine
  7. Kinyoun Acid Fast
  8. Field’s stain
A

1. Giemsa

  • Nuclei stain purple, cytoplasm stain blue to pale pink, eosinophils stain orange
  • Trypanosomes (e.g. Trypanosoma brucei, Trypanosoma cruzi, Leishmania spp)
  • Chlamydia
  • Cytomegalovirus (owl-eye viral inclusions)

2. India ink

  • Cryptocccus neoformans (halo sign)

3. Periodic acid-Schiff stain

  • Candida
  • Tropheryma whippelii (AKA Whipple’s disease) shows deposition of macrophages

4. Silver stain

  • Pneumocystis jiroveci
  • Legionella pneumophilia
  • Helicobacter pylori
  • Aspergillus
  • HIV
  • NOTE: the methenamine silver stain is used for FUNGI e.g. pneumocystitis, candida, aspergillus

5. Ziehl-Neelsen

  • Acid fast bacilli turn red, if not, stain remains blue
  • Mycobacterium tuberculosis
  • Cryptosporidium spp.

6. Auramine-Rhodamine

  • Mycobacterium = red/yellow
  • Not as specific as ZN stain, but more affordable and more sensitive

7. Kinyoun Acid Fast

  • AKA modified ZN test
  • Cryptosporidium parvum (causes diarrhoea in immunocompromised)

8. Field’s stain

  • Stain is made up of Methylene blue + Eosin Y
  • Plasmodium (thick blood films)
251
Q

SUMMARY CARD:

What are some tests for the following fungal infections:

  1. Tinea / trychophyton
  2. Cryptococcus
  3. Pneumocystitis
  4. Candida
  5. Aspergillus
  6. Histoplasmosis

think stains, antigens etc.

A

NOTE: gold standard for fungal infections is culture, however, takes many weeks to grow so these tests can be done in the mean time:

1. Tinea / trychophyton = KOH mixed with nail clippings

2. Cryptococcus = India ink stain, glucuronoxylomannan antigen test

3. Pneumocystitis = periodic acid-schiff (PAS) stain or silver stain, beta-D-glucan antigen test

4. Candida = methenamine silver stain or PAS, beta-D-glucan antigen test

5. Aspergillus = methenamine silver stain or PAS, galactomannan antigen test

6. Histoplasmosis = fungal serology

252
Q

DISEASE:

Guess the microbe seen with the following stains:

  1. Owl eyes on Giemsa stain
  2. KOH with nail clippings
  3. Zielh-Neelson - turns red
  4. Kinyoun acid fast
  5. Auramine-rhodamine - turns bright yellow
  6. Field’s stain
  7. Methenamine silver
  8. Periodic acid-Schiff stain
  9. India-ink with halo sign
  10. Beta-D-glucagon antigen
  11. Galactomannan antigen
  12. Glucoronoxylomannan antigen
A
  1. CMV
  2. Tinea / trychophyton
  3. Mycobacterium tuberculosis
  4. Cryptosporidium parvum
  5. Mycobacterium tuberculosis
  6. Plasmodium (thick film)
  7. Pneumocystitis, candida, aspergillus
  8. Candida, pneumocystitis, aspergillus, whipple’s disease
  9. Cryptococcus neoformans
  10. Pneumocystitis, candida
  11. Aspergillus
  12. Cryptococcus
253
Q

SUMMARY CARD:

What microbes are grown on the following agars:

  1. Buffered charcoal yeast extract
  2. Bordet-Gengou (potato) agar
  3. Eaton Agar
  4. Chocolate agar
  5. Thayer Martin media (chocolate agar variant)
  6. Castaneda medium
  7. Lowenstein Jensen media
  8. Blood agar
  9. MacConkey agar
  10. Czapek Dox Agar
  11. Novy-Macneal-Nicolle medium
  12. Sabouraud agar

Nice Homes have chocolate; * Lactating pink monkeys; BORDETella

A

1. Buffered charcoal yeast extract = legionella pneumophila

2. Bordet-Gengou (potato) agar = bordetella pertussis

3. Eaton agar = mycoplasma pmeumoniae

4. Chocolate agar = haemophilus influenzae, haemophilus ducreyi

5. Thayer Martin media (chocolate agar variant) = neisseria meningitidis, neisseria gonorrhoeae

NOTE: for thayer-martin, add vancomycin (inhibits Gram positives) + polymyxin (inhibits gram negatives) + nystatin (inhibits fungi)

6. Castaneda medium = brucellosis

7. Lowenstein Jensen media = mycobacterium species → brown coffee coloured (buff), bread-crumb like (rough), sticks to bottom of growth plate (tough) = Mycobacterium tuberculosis

8. Blood agar = alpha haemolytic (green agar - partial) = streptococcus pneumoniae + viridans; beta haemolytic (pale agar - partial) = GAS, GBS

9. MacConkey agar = pink with lactose fermenters e.g. E.coli, Klebsiella, Enterobacter

10. Czapek dox agar = aspergillus

11. Novy-Macneal-Nicolle medium = leishmania

12. Sabouraud agar = fungi

  1. Tellurite agar or Loeffler’s media = corynebacterium diptheriae

Year 5: Pathology (5 decks)

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