Myocarditis

Question 1

Define myocarditis

Answer 1

Inflammation of myocardium, associated with pericardial inflammation, in the absence of the predominant acute or chronic ischaemia characteristic of coronary artery disease.

Question 2

Aetiology of myocarditis

Answer 2

Idiopathic (50%)
Viral e.g. Enteroviruses, adenoviruses, Influenza A and B, coxsacki B virus, Dengue, Hepatitis, mumps, rubeola, Polio, Rubella, EBV
Bacterial e.g. mycobacterial, streptococcal species, mycoplasma pneumoniae, treponema pallidum, TB, staphylococcus, Clostridium species, diptheria
Spirochaetes e.g. Leptospirosis, syphilis, Lyme disease
Protozoa e.g. Chagas, Leishmania, toxoplasmosis
Drugs e.g. cyclophosphamide, trastuzumab, penicillin, chloramphenicol, sulphonamides, methyldopa, spironolactone, phenytoin, carbamazepine
Toxins e.g. cocaine, lithium, alcohol, lead, arsenic
Immunological e.g. SLE, sarcoid, Kawasaki, scleroderma, heart transplant rejection

Question 3

Symptoms of myocarditis

Answer 3

Flu-like prodrome (due to viral cause)

Chest pain
Dyspnoea
Orthopnoea
Fatigue
Palpitations
Syncope

Question 4

Signs of myocarditis on examination

Answer 4

Obs:
- Hypotension
General
- Elevated neck veins
- Lymphadenopathy
- Altered sensorium
Cardio
- Pericardial friction rub
- S3 gallop
- Sinus tachycardia
- Atrial and ventricular arrythmias
Resp
- Rales (abnormal

Question 5

investigations for myocarditis

Answer 5

ECG: non-specific ST-segment changes (Looks like pericarditis) + T wave abnormalities

Troponin: raised (differentiates from pericarditis)
CRP/ESR: raised
Serum CK/CK-MB: raised
BNP: raised

CXR: bilat. pulmonary infiltrates due to CHF
Echo: Global and regional left ventricular motion abnormalities and dilatation + Diastolic dysfunction
Cardiac MRI: early enhancement
Biopsy; myocardial cellular infiltrates +/- myocardial necrosis
Coronary angiography: exclude MI

Question 6

Management for myocarditis

Answer 6

Haemodynamically stable
No evidence of LV dysfunction: supportive

LV dysfunction:
- ACEi/RB
- Treat underlying cause e.g. steroids for hypersensitivity, autoimmune
- Consider IVIG
- Consider beta bloc

Unstable: arterial vasodilator e.g. sodium nitroprusside

Question 7

Complications of myocarditis

Answer 7

Atrial fibrillation
Ventricular tachyarrhythmias
Dilated cardiomyopathy
Sudden cardiac death
Multisystem organ failure