Write a short note on pericardial disease — acute pericarditis, pericardial effusion, tamponade and constrictive pericarditis.

Acute Pericarditis

Definition: inflammation of the pericardium. Diagnosis requires at least 2 of 4 criteria:

1. Characteristic chest pain — sharp, pleuritic, worse on inspiration and lying flat, RELIEVED BY SITTING FORWARD

2. Pericardial friction rub — a superficial scratchy sound, best heard at the left sternal edge with the patient leaning forward, and characteristically evanescent (may come and go within hours)

3. Characteristic ECG changes — WIDESPREAD (concave, "saddle-shaped") ST ELEVATION with PR DEPRESSION, not confined to a coronary territory

4. New or worsening pericardial effusion

Causes:

• Idiopathic / viral (the commonest in developed settings) — coxsackie, echovirus, adenovirus, influenza, HIV
• TUBERCULOSIS — the commonest identifiable cause in India and the leading cause of constriction
• Bacterial (purulent) — staphylococcal, pneumococcal; often from adjacent infection or septicaemia
• Post-myocardial infarction — early (epistenocardiac) and late (Dressler's syndrome, autoimmune, at 2–6 weeks)
• Uraemia — an indication for dialysis
• Malignancy — lung, breast, lymphoma, mesothelioma
• Autoimmune — SLE, rheumatoid arthritis, scleroderma
• Post-cardiac surgery or radiation; trauma; drugs (hydralazine, procainamide, isoniazid)
• Hypothyroidism (usually with effusion)

Distinguishing pericarditis from STEMI on ECG — a common and important problem:

Management:

• NSAIDs or high-dose aspirin (preferred after myocardial infarction) as first-line, PLUS COLCHICINE — which significantly reduces recurrence and should be given routinely for several months
• restrict strenuous exercise until symptoms resolve and inflammatory markers normalise
• corticosteroids only for specific indications (autoimmune disease, uraemic pericarditis, or failure of first-line therapy), since steroids increase the risk of recurrence
• treat the underlying cause — antitubercular therapy with steroids for tuberculous pericarditis, drainage and antibiotics for purulent disease, dialysis for uraemia.

Pericardial Effusion

Accumulation of fluid in the pericardial space. The haemodynamic consequence depends on the RATE of accumulation, not the volume — a rapidly accumulating 200 mL can cause tamponade, while a slowly accumulating 1–2 litres may be tolerated because the pericardium stretches.

Features:

• may be asymptomatic
• dyspnoea, chest discomfort, muffled heart sounds, Ewart's sign (dullness with bronchial breathing below the left scapula from compression of the left lower lobe). Chest X-ray shows a globular, "water-bottle" cardiac silhouette (with a clear lung field, distinguishing it from heart failure)
• ECG shows low voltage complexes and, in large effusions, ELECTRICAL ALTERNANS (beat-to-beat variation in QRS amplitude as the heart swings within the fluid).
• Echocardiography is the definitive investigation.

Cardiac Tamponade

Definition: a life-threatening condition in which pericardial fluid raises intrapericardial pressure sufficiently to impair diastolic filling of the heart, reducing stroke volume and cardiac output.

Clinical features:

• BECK'S TRIAD: hypotension, raised JVP, and muffled heart sounds
• Tachycardia with a thready pulse; cool peripheries; oliguria
• PULSUS PARADOXUS — an inspiratory fall in systolic blood pressure of more than 10 mmHg (an exaggeration of the normal fall). It results from ventricular interdependence within a fixed pericardial space: inspiratory increase in right ventricular filling pushes the septum leftwards and reduces left ventricular filling.
• Raised JVP with a PROMINENT X DESCENT and an ABSENT Y DESCENT — because filling is restricted throughout diastole
• KUSSMAUL'S SIGN IS CHARACTERISTICALLY ABSENT in tamponade but PRESENT in constrictive pericarditis — a valuable discriminator
• Dyspnoea, agitation, and progression to shock and pulseless electrical activity

Investigations:

• ECHOCARDIOGRAPHY — urgent and diagnostic: pericardial effusion with diastolic collapse of the right atrium and right ventricle, a dilated non-collapsing inferior vena cava, and marked respiratory variation in mitral and tricuspid inflow. ECG — low voltage, electrical alternans.
• Do not delay treatment for imaging in a peri-arrest patient.

Management:

• URGENT PERICARDIOCENTESIS — the definitive, life-saving treatment, performed under echocardiographic guidance where possible; surgical drainage (subxiphoid window) for loculated, recurrent or malignant effusions and for purulent pericarditis.
• Intravenous fluids to maintain preload as a temporising measure.
• AVOID diuretics, vasodilators and positive-pressure ventilation, all of which reduce preload and can precipitate cardiovascular collapse.
• Send the fluid for cell count, protein, glucose, cytology, Gram stain, AFB with CBCNAAT, ADA and culture — the diagnostic yield is high and, in India, tuberculosis must always be sought.
• Treat the underlying cause and arrange follow-up; recurrence is common with malignancy.

Constrictive Pericarditis

Definition: a rigid, thickened, often calcified pericardium encases the heart and restricts diastolic filling. Unlike tamponade, filling in early diastole is unimpeded (the ventricle fills rapidly until it reaches the limit of the shell), then abruptly halts.

Causes:

• TUBERCULOSIS — the commonest cause in India and other endemic regions
• post-cardiac surgery
• mediastinal radiation
• recurrent viral or idiopathic pericarditis
• connective tissue disease
• uraemia
• purulent pericarditis.

Clinical features — predominantly RIGHT heart failure with a "normal-sized" heart:

• Marked raised JVP with PROMINENT X AND Y DESCENTS (the rapid y descent reflecting rapid early filling)
• KUSSMAUL'S SIGN — a paradoxical RISE in JVP on inspiration (the rigid pericardium prevents the right heart from accommodating increased venous return)
• PERICARDIAL KNOCK — an early diastolic sound as filling stops abruptly
• Hepatomegaly, ASCITES (often disproportionate to peripheral oedema), and peripheral oedema; cachexia in chronic cases
• Pulsus paradoxus is usually ABSENT or mild (in contrast to tamponade)
• Fatigue and exertional dyspnoea; atrial fibrillation

Investigations:

• chest X-ray — PERICARDIAL CALCIFICATION (best seen on the lateral film; virtually diagnostic when present, and classically tuberculous)
• ECG — low voltage, atrial fibrillation, non-specific T changes
• echocardiography — septal bounce, respiratory variation in ventricular filling, dilated IVC
• CT or cardiac MRI — the best demonstration of pericardial thickening and calcification
• cardiac catheterisation — equalisation of diastolic pressures with the "square root" or "dip and plateau" sign.

Management:

• PERICARDIECTOMY — the definitive and potentially CURATIVE treatment, and it should not be delayed until the patient is cachectic and has hepatic dysfunction, since operative mortality rises steeply with advanced disease.
• Antitubercular therapy with corticosteroids where tuberculosis is the cause — and in early tuberculous constriction, medical therapy alone may prevent progression. Diuretics provide symptomatic relief while awaiting surgery.