Infectious Diseases Flashcards

1
Q

What organism causes Rheumatic fever?

A

Group A streptococcus

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2
Q

What are the major features of acute rheumatic fever?

A
  • Carditis
  • Poly arthritis
  • Chorea - abnormal mvmt
  • Subcutaneous Nodules
  • Erythema Marginatum
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3
Q

What is the treatment for ARF?

A
  • single dose benthazine penicillin or 10 days penicillin oral
  • arthritis/fever - paracetamol or aspirin/naproxen once diagnosis confirmed
  • carditis HF - bed rest, diuretics and restrict fluids
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4
Q

What is the vegetation in endocarditis? where are they most common?

A

(1) endothelium damage leads to platelet-fibrin deposition
(2) trauma and bacteraemia
both lead to adherence, colonisation and a mature vegetation
commonly aortic or mitral

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5
Q

What are high risk cardiac lesions that increase the chance of vegetations?

A
  • Prosthetic heart valves
  • Cyanotic congenital heart disease
  • Previous infective endocarditis
  • Mitral valve prolapse with significant regurgitation
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6
Q

What is the progression of infection that leads to heart failure?

A
  • Infection spreads from base of vegetation forming abscesses
  • Valve failure - perforation of leaflets and chord tendinae rupture
  • Heart failure secondary to severe regurgitation
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7
Q

What are some classical features of endocarditis?

A
  • Splinter haemorrhages
  • sub-conjunctival haemorrhages
  • Clubbing of the fingers
  • Splenomegaly
  • Osler’s Nodes
  • Janeway lesions
  • Roth spots
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8
Q

What investigations are required for a definitive diagnosis of endocarditis?

A
Routine blood tests - CRP/ESR
Urine sediment
Cxr
ECG
Echocardiography
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9
Q

Common causes of infectious rhinitis, pharyngitis and layrngitis

A

Rhinitis - adenovirus, rhinovirus
Pharyngitis - RSV, influenza, staph aureus, beta haemolytic strep
Laryngitis - RSV, H influenza, beta haemolytic strep

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10
Q

Routes of infection in respiratory tract infection

A
  • aspiration
  • inhalation
  • haematogenous
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11
Q

Normal defence mechanisms of resp tract

A
  • mucocilliary apparatus
  • intact epithelial surfaces
  • alveolar macrophage/inflammatory cells
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12
Q

How might pneumonia be classified?

A

Aetiological agent: strep pneumoniae, H influenza, moraxella catarrhalis, mycoplasma
Pathological/anatomical: lobar, bronchopneumonia
Syndromes: CAP, HCA, HA, chronic, necrotising and lung abscess

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13
Q

Bacterial cause of community acquired pneumonia

A
  • strep pneumoniae
  • haem influenza
  • mortadella catarrali
  • staph aureus
  • klebsiella pneumoniae
  • pseudomonas pneumoniae
  • legionella pneumoniae
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14
Q

4 Stages of inflammatory response in acute bacterial pneumonia

A
  1. congestion - lung is heavy and boggy
  2. red hepatisation - firm, red, airless, exudate of RBC
  3. grey hepatisation - grey brown and dry lungs, persistence of fibrin and neutrophils
  4. resolution - exudate undergoes enzymatic digestion and debris absorbed
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15
Q

Atypical community acquired pneumonia causes

How do they manifest?

A
  • mycoplasma pneumoniae
  • influenza
  • adenovirus
  • rhinovirus
  • VZV
  • Chlamydia pneumoniae
    May present as severe URTI, varied features
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16
Q

Health care associated pneumonia causes

A
  • MRSA

- P. aeruginosa

17
Q

Hospital acquired pneumonia causes

A
  • enterobacteriaecea
  • pseudomonas spp
  • MRSA
  • Strep pneumoniae
18
Q

Which type of pneumonia is commonly polymicrobial?

A

Aspiration - often from gastric contents

Often causes necrotising pneumonia with abscess

19
Q

Causes of pneumonia in immunocompromised host

A
  • pseudomonas aeruginosa
  • mycobacterium
  • legionella listeria monocytogenes
  • herpes
  • CMV
20
Q

Common agents of chronic pneumonia

A
  • bacterial Mycoplasma tuberculosis
  • actinomycetes
  • nocardia
  • fungal
21
Q

What is primary, secondary, progressive and milliary tuberculosis?

A

Primary: inhaled bacilli implant and Ghon Focus forms, 95% of the time CMI controls it
Progressive primary - massive haematogenous dissemination
Or can remain latent until secondary TB
Secondary: apical consolidation, progressive fibrosis
Progressive pulmonary TB: expanded area of caseation, erosion into airway creates cavity
Milliary: systemic/pneumonia

22
Q

HACEK organisms

A
Haemophilic parainfluenza 
Aggregatibacter actinomycetemcomitans
Cardiobacterium hominis 
Eikenella corrodes 
Kingella Kingae
23
Q

Common causes of bacterial endocarditis

A
  • streptococci viridans

- Staph. aureus

24
Q

Subacute and acute presentation of bacterial endocarditis

A

Subacute - weeks of low grade fever, anaemia, weight loss

Acute neurological event - CVA, meningitis, toxic encephalopathy

25
Q

Classical features of bacterial endocarditis

A
  • splinter haemorrhages
  • clubbing
  • splenomegaly
  • Osler’s nodes
  • Janeway lesions - palms/soles
  • roth spots - eyes
26
Q

Duke’s criteria for definitive diagnosis of endocarditis

A

2 major criteria: + blood culture for infective endocarditis, and evidence of endocardial involvement
OR 1 major and 3 minor OR 5 minor
Minor criteria: predisposition, fever, vascular phenomenon, immunologic phenomena, ECG, microbiological evidence

27
Q

Empiris bacterial endocarditis treatment for native and prosthetic valve:

A

Native: IV ben.pen, + IV fluclox, + IV gentamicin

Prosthetic: IV vancomycin + IV gentamicin

28
Q

Rheumatic fever

A

Post infectious immune mediated disease 2-4 weeks after GAS pharyngitis

29
Q

Modified Jones criteria for RF

A
MAJOR
Carditis
Arthritis 
Subcutaenous nodules 
Syndenhams chorea
Erthema margintum
MINOR: arthralgia, fever, elevated ACP, evidence of GAS on culture, prolonged PR, previous ARF
---- NEED: 2 major or 1 major + 2 minor
30
Q

Typical and atypical symptoms of pneumonia

A

Typical: fever, chills, cough, chest pain
Atypical: myalgia, arthralgia, headache, GI

31
Q

Physical examination of pneumonia

A
  • tachycardia
  • elevated RR
  • reduced O2 saturation
  • reduced air flow in affected lung
  • added sounds - crepitations etc
32
Q

3 components in diagnosis of pneumonia

A
  1. blood test - FBC, inflamm markers, blood culture
  2. Radiology - CXR, CT
  3. Microbiological - sputum gram stain and culture, serological for antibodies 4x rise in IgM, and molecular like throat swab for PCR
33
Q

Treatment for mild CAP

A

Amoxicillin oral

- use doxycycline or clarithromycin if atypical suspected

34
Q

Treatment of moderate CAP

A
IV penicillin (ceftriaxone if allergy)
- oral doxycycline/clarithromycin if atypical suspected
35
Q

Treatment of severe CAP

A

IV ceftriaxone or penicillin
+ Azithromycin to cover atypical
+ Gentamicin often added IV

36
Q

Treatment for aspiration pneumonia

A

IV metronidazole

Tazocin covers all

37
Q

Health care associated pneumonia treatment

A

IV pipericillin-tazobactam (tazocin) OR IV cefepime

AND

IV gentamicin + IV vancomycin if MRSA suspected