Infectious Diseases Flashcards Preview

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Flashcards in Infectious Diseases Deck (54)
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1
Q

what is the definition of sepsis?

A

life threatening organ dysfunction caused by a dysregulated host response to infection

2
Q

what is the definition of septic shock ?

A

a subset of sepsis with profound circulatory cellualr and metabolic abnormalities, associated with greater risk fo mortality than sepsis alone

3
Q

what is the sepsis 6?

A
give O2 
give IV ABX 
Give fluids 
Measure lactate 
measure urine output 
take blood cultures
4
Q

what are teh most common tropical ifnections seen in lri?

A

typhoid (enteric) fever, dengue fever, and malaria

5
Q

what are teh commonest manifestations of travel related illnesses?

A
  • GI symptoms (D+V)
  • jaundice
  • reticuloendothelial change (lymphadenopathy, hepatosplenomegaly)
  • resp symptoms (cough, SOB)
  • rash
6
Q

what important questions in a Hx need to be asked to a perosn with a fever returnign from travel?

A
  • geographic region wihtin last 12 months !!!
  • duration and exact dates of travel
  • onset and nature of signs and symptoms
  • types of accom
  • exposures: insects, animals, freshwater lakes, canal warr
  • type of food/water consumed
  • sexual history,
  • PMHx and immunosuppressive therapy?
7
Q

what is the time frame of different infections? (dengue, viral, malaria, typhoid, HIV, baacterial, TB)

A

0-10 days: dengue, rickettsia, viral, gastrointestinal (bacteria, amoeba)
10-21 days: malaria, typhoid, primary HIV infection
>21 days: malaria, chronic bacterial infections, TB, parasitic infections

8
Q

what are some useful pre travel immunisations available?

A
vaccinations for: 
- Hep A, hep B 
- typhoid
- tetanus
- MMR 
- yellow fever
- rabies 
or malaria chemoprophylaxis
9
Q

what are some suggested investigations to do in a patient with fever and returned from travel?

A
  • FBC, LFTs, U+Es, electrolytes
  • malaria smears +/- antigen detection dipstick: at least 3 times over 24-48 hrs
  • blood cultures x2
  • urinalysis (+/- urine uclture)
  • stool culture +/- stool for ova, parasites, cysts
  • CXR
  • HIV, Hep B, Hep C, syphillis serology
  • acute serology tube to be saved in lab
10
Q

how is malaria transmitted?

A

night biting Anopheles mosquitoes

11
Q

what are the different types of plasmodium species of malaria?

A
plasmodium falciparum (90% africa)- most serious adn most common 
plasmodium vivax (SE asia)
plasmodium ovale (SE asia)
12
Q

what is teh presenation of a patient with malaria

A
  • abrupt onset of rigors
  • high fevers
  • malaise
  • severe headache
  • myalgia
  • vague abdo pain
  • nausea + vomiting
  • diarrhoea
  • jaundice and hepatosplenomegaly
13
Q

what are teh blood results like in a patient with malaria ?

A

anaemic
thrombocytopenic
leukopenic
abnormal liver enzymes

14
Q

what are teh complications that can occur with p. falciparum malaria when untreated?

A
  • hypoglycaemia
  • renal failure
  • pulmonary oedema
  • neurologic deterioation
  • death
15
Q

what is the treatment for malaria (specifying with plasmodium specied)

A

P. falciparum - IV artesunate (+quinine and doxycycline for 7 days)
P. vivax and P.ovale - chloroquine (3-4 days) and primaquine (14 days)

16
Q

where are the most common areas in the world to get typhoid fever?

A

SE asia

Southern and Central America

17
Q

what are the signs of symptoms of a patient with typhoid fever?

A
sustained fever
anorexia
malaise
vague abdo discomfort 
constipation 
diarrhoea
dry cough 

pulse temperature dissociation (low pulse)
heptosplenomegaly
rose spots (30-50% patients)

18
Q

what are the common blood test results for patients with typhoid fever?

A

leucopenia
lymphopenia
raised CRP

19
Q

what investigative results are needed to diagnose typhoid fever?

A
isolation of organism in cultures of blood (80% if 2 cultures taken) - gram negative rod of salmonella typhi 
stool 
urine 
bone marrow 
duodenal aspirates
20
Q

what is the treatment for typhoid fever?

A
  • IV ceftriaxone 2g OD

- switch to PO ciprofloxacin 500mg BD or PO azithromycin 500mg OD once sensitivities known

21
Q

what is enteric fever?

A

overarching name including typhoid fever

it encapsulates the bacterial infections caused by salmonell atyphi and salmonella paratyphi

22
Q

what is the classical definition of pyrexia of unknown origin?

A
  • temp >38 on multiple occasions
  • illness of >3 wks
  • no diagnosis despite >1 wks worth of inpatient

most commonly occurs when patients appear on ward afetr being transferred from other specialities

23
Q

what are the common cuases of pyrexia of unknown origin?

A

infective - TB, abcesses, infection endocarditis, brucellosis
autoimmune/connective tissue - adult onset Stills disease, temporal arteritis, Wegeners granulomatosis
neoplastic - leukamias, lymphomas, renal cell carcinoma
other - drugs, thromboembolism, hyperthyroidism, adrenal insufficiency

24
Q

what are teh common examination findings in a patient with fever of unknown orgin?

A
  • enlarged lymph nodes
  • stigmata of endocarditis (janeway lesions, roth spots, osler nodes, splinter heamorrhages)
  • evidence of weight loss
  • joint abnormalities
25
Q

what are teh managment points for a patient with fever of unknown origin?

A
  • establish diagnosis !
  • get seen by rheumatology or heamatolog y
  • stable patients can be managed as outpatients
  • stay up to date on tests done
26
Q

what is the pathogenesis of TB?

A
  • transmitted by aerosol inhalation and cuases pulmonary infection, then spreads via heamatogenous sread to any site in body
  • initial infection can be asymptomatic - lie dormant for years (latent) then reactivate to cuase active infection
  • lifetime reactivation risk = 10-15% (usually due to immunosuppression, HIV infection or advancing age)
  • common to experience reactivation when migrating to UK from endemic areas
27
Q

what are the screenign tests of identifying latent TB?

A

CXR and measurement of interferon gamma (quantiFERON or T spot)

28
Q

what is the quantiFERON test?

A

assesses the amount of interferon gamma released by T cells when they are exposed to proteins found on mycobacterium. pre exposed cells release more interferon
DOES NOT DIFFERENTIATE between active and latent TB and is not used to diagnose active TB
(patients with immunosupression may not release interferon gamma)

29
Q

what is the T spot test?

A

similar to quantiFERON test but instead of testing whole blood, lymphocytes are isolated and tested directly

30
Q

what are teh risk factors for having latent TB?

A
  • immigrants from high prevalence coutnries
  • healthcare workers
  • HIV +ve patients
  • patients starting on immunisuppression
31
Q

what is teh treatment for latent TB?

A

3 months rifampicin and isoniazid or 6 months rifampicin alone

  • treatment reduces risk for reactivation - needs to be balances against risk fo heptotoxicity
  • pts age > 35 increaed risk of hepatotoxicity therefore advise against nto treating unless have TB risk factors
32
Q

what are teh common symptoms of active TB?

A
  • non resolving cough
  • unexplained persistant fever
  • drenching night sweats
  • weight loss
33
Q

what are the common signs of active TB?

A
  • clubbing
  • cachexia
  • lymphadenopathy
  • hepato/splenomegaly
  • erythema nodosum
  • crepitations or bronchial breathing with pleural effusion
  • pericardial rub
34
Q

what investgiations should be doen when active TB is suspected?

A

CXR: mediastinal lymphadenopathy or a cavitating pneumonia or pleural effusion among other signs
CT: lymphadenopathy. nodes with central necrosis and lesions in viscera
MRI: leptomeningeal enhancement in TB meningitis

35
Q

what biopsy/samples need to be taken when an active TB infection is suspected? (for diff types of TB)

A

NEED TO CULTURE BACTERIA - culutres cna take 6 wks so ATT is usually started after samples taken:

  • pulmonary TB: sputum samples and bronchoscopy (+/- EBUS) on pulmonary lymph nodes if ‘smear negative’
  • meningeal TB: lumbar puncture for TB culture and TB PCR
  • lymph node TB: core biopsy of lymph node
  • pericardial TB: pericardiocentesis
  • gastrointestinal TB: coloscopy and bowel biopsy
36
Q

what is the main distinguishing feature found on histology which diagnoses active TB

A

caseating/necrotising granulomatous inflammation

37
Q

what is the paradoxical reaction from TB treatment?

A

when there is an increase in inflammation as bacteria die causing worsening symptoms - usually occurs at start of treatment and steroids can sometimes be given

this reaction can be fatal if in TB meningitis (therefore alwasy give steroids at start of TB meningitis treatment)

38
Q

what are the symptoms of TB meningitis?

A

personality change
headache
meningitis symptoms
comatosed

need lumbar puncture ! - shows high protein, low glucose and lymphocytosis

39
Q

what is miliary TB?

A

miliary Tb is widespread and found in multiple sites ( CNS/bone marrow/pericardium)
all pts. need neuroimaging +/- lumbar puncture to exclude CNS involvment
treatment started ASAP

40
Q

what is the treatment for TB?

A

2 months - RIPE (plus pyridoxine)
+ 4 months - RI (plus pyridoxine

Rifampicin
Isoniazid
Ethambutol
Pyrazinamide

41
Q

what are the main side effects of rifampicin?

A
  • causes urine/tears to turn orange

- drug induced hepatitis +

42
Q

what are the mian side effects of isoniazid?

A
  • peripheral neuropathy
  • colour blindness
  • drug induced hepatitis ++
43
Q

what are the main side effects of ethambutol?

A

optic neuropathy/reduced visual acuity

44
Q

what are teh main side effects of pyrazinamide?

A

drug induced hepatitis +++

45
Q

what monitoring is needed throughout TB treatment?

A

before: measure baseline LFTs and visual acuity
during: monitor LFTs

46
Q

what kind of infection control is important with a pt. withh TB?

A
  • side room !
  • after 2 weeks of treatment then considered non infectious to immunocompetent ppl (stay away from immunocompromised still!!)
  • smear +ve can be discharged but need to isolate @ home for first 2 wks still
47
Q

when should screening for bacterial STIs be performed in patients?

A
  • all patinets who are already knwon to have an STI
  • all patinets who request testing
  • any patient indentified to be at high risk of STI from their history
48
Q

what different swabs are used to test for gonorrhoea and chlamydia?

A
  • first pass urine (men only) - urethral GC/CT
  • vulvovaginal swab - vaginal/cervical GC/CT
  • pharyngeal swab - GC/CT of throat
  • rectal swab - GC/CT of rectum
49
Q

what then happens to the swabs taken from the patients?

A

sent to virology -> NAATs (PCR) confirms/denies presence of batceria

50
Q

what additionnal testing for STIs can be done for other particualr symptoms ?

A
  • urethral discharge (gonococcal culture)
  • vaginal discharge (swab from cervical os and post. fornix)
  • oral/genital ulceration (viral swab fro HSV1+2)
  • anal discharge (gonococcal culture)
  • conjuctivitis (GC/CT form conjuctiva + gonococcal culture)
51
Q

what are the baseline investgiations for a patient with newly diagnosed HIV/

A
  • confirmatory HIV test
  • CD4 count
  • HIV viral load
  • HIV resistance profile
  • serology for syphilis, hep B, hep C, hep A
  • toxoplasma IgG, measles IgG, varicella IgG, rubella IgG
  • FBC, U+Es, LFTs, bone profile, lipid profile
  • schistosoma serology (if spent >month in subsaharan africa)
  • ## annual cervical cytology
52
Q

what vaccinations do patients with HIV need?

A
  • hep B
  • pnuemococcus
  • annual flu vaccine
53
Q

what medication is given to patients with HIV?

A

antiretrovirals

54
Q

what is teh treatment for patients with low CD4 counts?

A
  • CD4<200 = co trimoxazole 480mg PO OD to prevent PC PCP

- CD4<50 = azithromycin 1250mg PO once weekly to prevent MAI (also need to be assessed for CMV retinitis)