Cardiology | SA/NT SAQ 2020.2 Q6

​Brain Food is a project to drip feed clinical knowledge (in the form of mock SAQs) to satisfy those hungry neurons. Sources are SA/NT Trial Exam 2020.2 and Monash 2022.1. Answers are prone to ageing. Leave a comment if you don't understand or something doesn't seem right...
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PS we don't use the mock questions uploaded to ACEMs official mock

​A 28 year old man presents to your regional emergency department with a two-day history of pleuritic central chest pain. He has no past medical history.

His vital signs are:
RR 28 / min
SaO2 99% on room air
HR 120 bpm (regular)
BP 90/60 mmHg
Temp 38.2oC

1. List two (2) important abnormalities on this ECG. (2 marks)

1. Sinus tachycardia
2. Widespread concave STE and PR depression (I, II, III, aVF, V4-6)
3. Reciprocal ST depression and PR elevation (V1 and aVR)

2. Apart from pericarditis, list two (2) other differential diagnoses and the most appropriate initial investigation for each in THIS patient. (4 marks)

1. Pneumonia - CXR
2. PE - D-dimer (no marks for CTPA)
3. Pneumothorax - CXR or lung USS
4. Aortic dissection - CT angiogram 
5. MI/myocarditis - troponin, TTE

He becomes distressed and hypotensive and is moved to the resus room where a cardiac ultrasound demonstrates a pericardial effusion. 

3. What are three (3) features of massive pericardial effusion causing tamponade on focused cardiac ultrasound? (3 marks)

1. Pericardial effusion >1.5cm
2. Diastolic right ventricular collapse
3. Systolic right atrial collapse
4. Plethoric IVC with minimal respiratory variation
5. Exaggerated respiratory cycle changes in mitral and tricuspid valve in-flow velocities as a surrogate for pulses paradoxus. 

An emergency pericardiocentesis is performed with improvement of his symptoms. He is admitted to hospital where he is subsequently diagnosed with myocarditis. 

4. In this patient, what are three (3) possible causes of myocarditis?

1. Viral - coxsackie B, HIV
2. Bacterial - TB, staph
3. Autoimmune - SLE
4. Giant cell
5. Toxins - amphetamines, cocaine, alcohol, heavy metals, electric shock