Pericarditis, pericardial effusion, tamponade and constriction

Overview

The pericardium is a double sac around the heart: an outer fibrous layer and an inner serous layer (parietal and visceral). A small amount of fluid lets the heart move freely.

Pericardial disease presents in four ways: acute pericarditis, pericardial effusion, cardiac tamponade and constrictive pericarditis. Tamponade is a life-threatening emergency; the other three are common MCQ themes because each has classic signs.

Acute pericarditis

Inflammation of the pericardium. It accounts for a small but real share of emergency chest pain, mostly in young men. Most cases are idiopathic (presumed viral).

Aetiology

Clinical findings

• Chest pain: sharp, central, pleuritic; worse lying flat, coughing and on deep breathing; eased by sitting up and leaning forward. May radiate to the trapezius ridge or shoulder tip (phrenic nerve supply of the parietal pericardium).
• Pericardial friction rub: scratchy sound, best heard at the left sternal edge with the patient leaning forward; may come and go.
• Fever, preceding viral illness.

Diagnosis

A diagnosis needs at least 2 of these 4:

1. Typical chest pain
2. Friction rub
3. Typical ECG changes
4. New or enlarging pericardial effusion

ECG

• Widespread concave-up ("saddle-shaped") ST elevation in many leads, not fitting a single coronary territory.
• PR segment depression (most specific early sign).
• Reciprocal ST depression only in aVR (and V1), with PR elevation in aVR.
• Later: ST returns to baseline, then T wave inversion; no Q waves.

Other investigations

• CRP and ESR raised (used to monitor response); white cell count may be raised.
• Troponin may rise if the myocardium is involved (myopericarditis).
• Echocardiography to look for effusion.
• Chest X-ray usually normal unless a large effusion.
• Urea and creatinine, TB tests, autoantibodies, thyroid function as guided by the history.

Management

• NSAID (ibuprofen 600–800 mg three times daily) or high-dose aspirin (750–1000 mg three times daily) for 1–2 weeks, plus colchicine (0.5 mg twice daily for about 3 months). Colchicine reduces recurrence.
• Add gastric protection.
• Avoid corticosteroids unless there is an autoimmune cause or the patient cannot take NSAIDs; steroids increase relapse.
• Restrict exercise until markers settle; competitive athletes wait at least 3 months.
• Admit high-risk patients: fever above 38°C, subacute onset, large effusion, tamponade, no response to treatment, or myopericarditis.
• Uraemic pericarditis: needs urgent dialysis.
• Post-MI (Dressler): aspirin; avoid other NSAIDs early after MI.

Tuberculous pericarditis

Rare in the West but a leading cause of pericarditis and large effusion in developing countries, including Pakistan, and very common with HIV. Presents with evening fever, night sweats, weight loss and features of pericarditis or effusion. Often leads to constriction. Treated with standard anti-TB drugs; prednisolone is sometimes added. Follow the current national TB programme guideline, which can change.

Pericardial effusion

Fluid in the pericardial space. It can be serous, purulent, blood-stained (malignancy, TB, trauma, aortic dissection) or chylous.

Acute vs chronic

• Rapid accumulation (trauma, cardiac rupture, dissection, after cardiac surgery): even a small volume can cause tamponade, because the stiff pericardium cannot stretch quickly.
• Slow accumulation (hypothyroidism, uraemia, malignancy, TB): the pericardium stretches, so large volumes collect with few symptoms.

Clinical features

• Symptoms of the cause; breathlessness and chest discomfort if large.
• Soft, distant heart sounds; impalpable apex.
• A rub can be heard early but fades as fluid separates the layers.
• Ewart's sign: dullness and bronchial breathing below the left scapula from compression of the lung base.

Diagnosis

• Echocardiography: the test of choice; shows the fluid as a dark space around the heart and its size.
• ECG: low-voltage QRS complexes, sinus tachycardia, electrical alternans (beat-to-beat change in QRS height) with large effusions.
• Chest X-ray: large, globular ("water bottle") heart with sharp borders and clear lung fields.
• CT or MRI for loculated or posterior effusions (for example after surgery).
• Pericardial fluid analysis (protein, cells, cytology, Gram stain, culture, ADA for TB) when the cause is unclear, especially if TB, malignancy or pus is suspected. Pericardial biopsy if TB is still suspected.

Management

Treat the cause; many effusions settle. Drain if there is tamponade, or for diagnosis. Recurrent malignant effusions may need a pericardial window (fenestration).

Cardiac tamponade

Definition: pericardial fluid under pressure compresses the heart and prevents filling, so stroke volume and cardiac output fall. It is obstructive shock and an emergency.

Signs and symptoms

• Breathlessness, chest discomfort, dizziness, collapse.
• Beck's triad: hypotension, raised JVP, muffled (quiet) heart sounds.
• Tachycardia and cold peripheries.
• Pulsus paradoxus: an exaggerated fall in systolic BP on inspiration, 10 mmHg or more. On inspiration the right ventricle fills more, the septum bulges left, and left ventricular output falls.
• JVP with a prominent x descent and an absent y descent.

Investigations

• Echocardiography (do not delay treatment if the patient is crashing): effusion with diastolic collapse of the right atrium and right ventricle, septal shift into the left ventricle on inspiration, and a dilated IVC that does not collapse on breathing.
• ECG: low voltage, electrical alternans, tachycardia.

Treatment

• Urgent pericardiocentesis: a needle is passed from the subxiphoid region, aiming towards the left shoulder, ideally under echo guidance. A drain can be left in.
• Support with IV fluids to keep filling pressure up while arranging drainage.
• Avoid diuretics and vasodilators: they reduce filling and worsen shock.
• Surgical drainage for trauma, cardiac rupture, aortic dissection, posterior or clotted collections.

Constrictive pericarditis

The pericardium becomes thick, fibrous and often calcified, encasing the heart and limiting diastolic filling. It develops slowly, so it is less acute than tamponade.

Causes

• Tuberculosis (commonest in developing countries).
• After cardiac surgery or mediastinal radiotherapy.
• Any previous pericarditis, haemopericardium, purulent pericarditis.
• Connective tissue disease; idiopathic.

Clinical features

Mainly right-sided congestion with relatively clear lungs:

• Raised JVP with a steep, deep y descent (Friedreich's sign).
• Kussmaul's sign: the JVP rises on inspiration instead of falling.
• Pericardial knock: an early diastolic sound (filling stops abruptly).
• Hepatomegaly, ascites (often out of proportion to leg oedema), peripheral oedema.
• Fatigue, low output, atrial fibrillation in some.
• Pulsus paradoxus can occur but is less common than in tamponade.

Investigations

• Chest X-ray: pericardial calcification (best seen on the lateral view) and a small or normal-sized heart despite heart failure.
• ECG: low voltage, T wave flattening or inversion, AF.
• Echocardiography: thick pericardium, small ventricles, septal bounce.
• CT or MRI: pericardial thickening (4 mm or more) and calcification.
• Cardiac catheter: equal diastolic pressures in all chambers with a "dip and plateau" (square root) pattern.

Treatment

Pericardiectomy (surgical stripping of the pericardium). Diuretics help symptoms only. Treat TB if present.

Tamponade vs constriction vs restrictive cardiomyopathy

Quick revision

• Pericarditis: pleuritic pain eased sitting forward, rub, saddle ST elevation, PR depression.
• Treat with NSAID or aspirin plus colchicine; avoid steroids; dialysis for uraemic pericarditis.
• Dressler syndrome: autoimmune pericarditis weeks after MI.
• Effusion: soft heart sounds, low voltage, globular heart on X-ray; echo confirms.
• Tamponade: Beck's triad, pulsus paradoxus, electrical alternans, RA and RV diastolic collapse.
• Tamponade treatment: urgent echo-guided subxiphoid pericardiocentesis; no diuretics.
• Constriction: Kussmaul's sign, steep y descent, pericardial knock, calcification, small heart.
• TB is a major cause of effusion and constriction in Pakistan.

Written by The House Job from standard references (Kumar and Clark's Clinical Medicine).

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