Myocarditis

Question 1

Define

Answer 1

DEFINITION: acute inflammation and necrosis of cardiac muscle (myocardium)

Question 2

Causes

Answer 2

Usually IDIOPATHIC

• Viruses (Coxsackie B, EBV, CMV, Adenovirus, Influenza
• Bacteria (Post-streptococcal, Tuberculosis, Diphtheria, Fungal, Candidiasis
• Protozoal (Trypanosomiasis (Chagas disease)
• Helminths (Trichinosis)

Non-infective

Systemic: SLE, sarcoidosis, polymyositis

Hypersensitivity myocarditis: sulphonamides

Drugs :Chemotherapy agents (e.g. doxorubicin, streptomycin)

Others : Cocaine, heavy metals, radiation

Question 3

Epidemiology

Answer 3

Incidence is difficult to measure accurately

Coxsackie B virus is most common in Europe and USA

Chagas disease is most common in South America

Question 4

Symptoms

Answer 4

Prodromal flu-like illness with:

• Fever
• Malaise
• Fatigue
• Lethargy

Breathlessness (due to pericardial effusion/myocardial dysfunction)

Palpitations

Sharp chest pain (suggesting there is also pericarditis)

Question 5

Signs

Answer 5

Signs of pericarditis

Signs of complications (e.g. heart failure, arrhythmia)

Question 6

Investigations

Answer 6

Bloods

FBC - raised WCC if infective cause

U&E

ESR/CRP - raised

Cardiac enzymes - may be raised

Tests to identify cause (e.g. viral/bacterial serology, ANA, TFT)

ECG

Non-specific T wave and ST changes

PERICARDITIS: widespread saddle-shaped ST elevation

H 5 ㄒ R P
CXR

May be NORMAL

May show cardiomegaly

Pericardial Fluid Drainage

Measure glucose, protein, cytology, culture and sensitivity

Helps identify causative organism

Echocardiography

Assesses systolic/diastolic function

Wall motion abnormalities

Pericardial effusions

Myocardial Biopsy

Rarely required