Myocarditis

Question 1

What is myocarditis?

Answer 1

Inflammation of cardiac muscle (myocardium).
- Usually young patients(19-35y/o) with acute history of recent flu-like illness and new onset chest pain.

Question 2

Summarise the epidemiology of myocarditis

Answer 2

● Incidence is difficult to measure accurately
- Predominantly affects young people aged 19 to 35 years old.
● Coxsackie B virus is most common in Europe and USA
● Chagas disease is most common in South America

Question 3

What causes myocarditis?

Answer 3

Usually IDIOPATHIC 

1. Viral: Coxsackie B (most common), EBV, CMV (Cytomegalovirus), influenza
2. Bacteria: Post-streptococcal, TB, diphtheria
3. Fungal: candidiasis
4. Protozoal: Chagas disease
5. Non-infective: SLE, sarcoidosis, polymyositis, hypersensitivity.
6. Drugs: chemotherapy
7. Cocaine, radiation

Question 4

What are the presenting symptoms of myocarditis?

Answer 4

1. Prodromal flu-like illness with:
   o Fever
   o Malaise
   o Fatigue
   o Lethargy
2. Breathlessness (due to pericardial effusion/myocardial dysfunction)
3. Palpitations
4. Sharp chest pain (suggesting there is also pericarditis)

Question 5

What signs of myocarditis can be found on physical examination?

Answer 5

● Signs of pericarditis
● Tachycardia
● Soft S1
● S4 gallop
● Signs of complications (e.g. heart failure, arrhythmia)

Question 6

What investigations are used to diagnose/ monitor myocarditis?

Answer 6

1. Endomyocardial Biopsy
2. 12-Lead ECG → ordered immediately in anyone with chest pain or cardiac symptoms. May see ST elevation and T wave inversion.
3. Bloods → increased cardiac enzymes (CK, CK-MB, Troponin), increased ESR, increased BNP
4. CXR → cardiac enlargement, pleural effusions, bilateral pulmonary infiltrates (pulmonary oedema)

Question 7

How is myocarditis managed?

Answer 7

1. Supportive Treatment → cardiac monitoring, oxygen administration, analgesics
2. Treat Cause → antibiotics for bacterial myocarditis, antimycotics for fungal infections
   - Patients with severe myocarditis may require ITU support and vasopressors
   - Patients with viral acute myocarditis may benefit from a course of corticosteroids.