2.5 Infective Endocarditis, Pericardial Disease, Myocarditis & Cardiomyopathies

Infective Endocarditis, Pericardial Disease, Myocarditis & Cardiomyopathies

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Infective Endocarditis (IE)

Infective endocarditis is infection of the endocardium, usually a heart valve. Risk factors include previous endocarditis, prosthetic valves, structural or congenital heart disease, intravenous drug use, indwelling lines, haemodialysis and poor dental health.

Organisms

Clinical Features

Fever with a new or changing murmur is endocarditis until proven otherwise. Other features include malaise, weight loss, splinter haemorrhages, Janeway lesions (painless palmar macules), Osler's nodes (painful finger-pulp nodules), Roth spots (retinal haemorrhages with pale centres), clubbing, splenomegaly, microscopic haematuria (glomerulonephritis) and embolic events (stroke, septic pulmonary emboli in right-sided disease).

Modified Duke Criteria

• Major: (1) typical organisms in two separate blood cultures (or persistently positive cultures); (2) evidence of endocardial involvement on echocardiography (vegetation, abscess, new prosthetic valve dehiscence) or new valvular regurgitation. The 2023 Duke-ISCVID update also accepts cardiac CT and PET-CT findings.
• Minor: predisposition (heart condition or IV drug use); fever of 38°C or higher; vascular phenomena (emboli, Janeway lesions, intracranial haemorrhage); immunological phenomena (glomerulonephritis, Osler's nodes, Roth spots, rheumatoid factor); positive cultures not meeting the major criterion.
• Definite IE: 2 major, or 1 major + 3 minor, or 5 minor.

Management

1. Take at least three sets of blood cultures from separate venepunctures before antibiotics (in a stable patient, they can be spaced out; do not delay treatment in sepsis).
2. Transthoracic echocardiography, then transoesophageal echocardiography if TTE is negative but suspicion remains, or for prosthetic valves and suspected abscess.
3. Empirical IV antibiotics per local microbiology guidance (for example amoxicillin with or without gentamicin for indolent native-valve disease; vancomycin plus gentamicin if acutely septic or if MRSA is possible; adding rifampicin for prosthetic valves), then targeted therapy for 4–6 weeks.
4. Surgery for heart failure from valve destruction, uncontrolled infection (abscess, persistent bacteraemia, fungal infection) or to prevent embolism from large vegetations.

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Acute Pericarditis

• Causes: viral (most common, including coxsackievirus), post-myocardial infarction (early, or Dressler's syndrome weeks later), uraemia, tuberculosis, malignancy, autoimmune disease, post-cardiac surgery.
• Features: sharp pleuritic chest pain relieved by sitting forward, radiating to the trapezius ridge; pericardial friction rub.
• ECG: widespread saddle-shaped (concave) ST elevation with PR depression, without reciprocal changes (unlike STEMI).
• Management: NSAID (for example ibuprofen) with gastroprotection, plus colchicine (usually for 3 months in a first episode) and restriction of strenuous exercise until symptoms and markers resolve. Admit high-risk patients (fever above 38°C, large effusion, tamponade, raised troponin, immunosuppression, anticoagulation or failure to respond).

Pericardial Effusion & Cardiac Tamponade

Tamponade occurs when fluid compresses the heart and impairs filling. Look for Beck's triad (hypotension, raised JVP, muffled heart sounds), pulsus paradoxus (a fall in systolic pressure of more than 10 mmHg on inspiration), tachycardia, and on ECG low voltages and electrical alternans. Echocardiography confirms it; the treatment is urgent pericardiocentesis (or surgical drainage).

Constrictive Pericarditis

A thickened, often calcified pericardium (after TB, radiotherapy or surgery) restricts filling, causing raised JVP that rises on inspiration (Kussmaul's sign), a pericardial knock, hepatomegaly, ascites and oedema. Treatment is pericardiectomy.

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Myocarditis

Inflammation of the myocardium, usually viral (for example coxsackievirus B), but also drug-related, autoimmune, or after mRNA COVID-19 vaccination (mainly young men). It presents with chest pain, breathlessness, palpitations or heart failure, with raised troponin and ECG changes. Cardiac MRI is the key non-invasive test. Management is supportive (heart failure treatment, arrhythmia monitoring) with avoidance of competitive sport for several months.

Cardiomyopathies

Acute Rheumatic Fever

An immune reaction 2–4 weeks after group A streptococcal pharyngitis. The revised Jones criteria need evidence of recent streptococcal infection plus 2 major, or 1 major and 2 minor, criteria. Major: carditis, polyarthritis, Sydenham's chorea, erythema marginatum, subcutaneous nodules. Minor: fever, arthralgia, raised ESR or CRP, prolonged PR interval. Long-term it causes mitral stenosis. Treat with penicillin and anti-inflammatory therapy, then secondary penicillin prophylaxis.