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Question 1

Advantages vs disadvantages of thrombolysis for submassive PE

Answer 1

Advantages
- Patients appear to feel better quicker.
- Clots resolve faster (30% to 35% reduction in total perfusion defect at 24h, with minimal improvement if just anticoagulated) early reduction in PAP and RV strain
- Decreased recurrence of PE
- Decreased death or hemodynamic stability (composite endpoint) at 7 days (PEITHO trial)
- Improved functional outcome (unproven, TOPCOAT trial)
- less long term pulmonary hypertension (MOPETT trial)

Disadvantages
- risk of intracerebral haemorrhage (2% in >75y group in PEITHO)
- risk of other haemorrhage (major bleeding, i.e. transfusion needed, ~6% in PEITHO)
- similar improvement at 7 days overall (65% to 70% reduction in total defect regardless of whether thrombolysed or anticoagulated)
- Increased cost
- No mortality benefit proven (improved composite of mortality and haemodynamic stability in PEITHO, as yet unpublished)
- Catheter-directed thrombolysis, if available, may be safer and equally effective
- RV dysfunction can markedly improve over 24 to 48h with systemic anticoagulation (e.g. heparin) in some patients

Question 2

What are some CXR changes associated with PE

Answer 2

Westermark sign - increased translucency of pulmonary vasculature distal to the thrombosis
Has specificity of 92% (low sensitivity 14%)

Hampton Hump - well defined pleural opacity representing hemorrhage and necrotic tissue following pulmonary infarction. Specificity 82% but sensitivity 22%

Dilated pulmonary arteries
Raised hemidiaphragem with basal atelectasis

Question 3

What are the criteria for massive and submassive PE

Answer 3

Massive PE - sustained hypotension (SBP<90 for at least 15 minutes), pulselessness or persistent profound bradycardia (HR<40 with signs of shock)

Submassive PE - Without sustained hypotension but with either RV dysfunction or myocardial necrosis

RV dysfunction -
- RV dilation (>0.9 LV diameter) on either apical 4 chamber or CT
- RV systolic dysfunction on TTE
- Elevated BNP or pro BNP
- New ECG changes (RBBB, anteroseptal ST changes or anterolateral T wave inversion)

Question 4

What clinical factors suggest anaerobic pneumonia and which bugs are involved

Answer 4

Risk factors for aspiration (CNS depression or swallowing dysfunction)
Severe periodontal disease
Fetid sputum
Pulmonary abscess or empyema

Anaerobic pneumonias are typically polymicrobial
- Bacteroides
- Fusobacterium
- Prevotella
- Peptostreptococcus

Question 5

How does S.Aureus pneumonia present

Answer 5

Associated with influenza
IVDU with hematogenous spread to both lungs with multiple small infiltrates or abscess
Often necrotizing with cavitation and pneumatocele