Key Facts

Acute pericarditis is inflammation of the pericardial layers (visceral and parietal pericardium). It is the most common pericardial disease encountered in clinical practice, presenting with chest pain, friction rub, and characteristic ECG changes.

Epidemiology

• Accounts for ~5% of emergency chest pain presentations
• More common in men (3:1)
• Peak incidence: young adults (20-50 years)
• Most common in spring/autumn (viral aetiology)

Aetiology

• Idiopathic/viral (~80-90%): Coxsackie B, echovirus, adenovirus, EBV, CMV, HIV, influenza, SARS-CoV-2
• Bacterial/purulent: S. aureus, S. pneumoniae, TB (especially in immunocompromised/developing countries)
• Autoimmune: SLE, rheumatoid arthritis, Dressler syndrome (post-MI, 2-10 weeks)
• Post-cardiac injury: post-pericardiotomy syndrome, post-MI (Dressler), post-traumatic
• Uraemic: CKD/dialysis
• Malignancy: lung, breast, lymphoma, melanoma
• Drugs: hydralazine, isoniazid, procainamide (drug-induced lupus)
• Radiation: post-mediastinal radiotherapy
• Hypothyroidism: myxoedema pericarditis

Pathophysiology

• Inflammation of pericardial layers causes exudation of fluid, fibrin, and inflammatory cells
• Friction between inflamed pericardial surfaces produces the friction rub
• Pericardial inflammation causes characteristic diffuse ST elevation (due to epicardial myocardial inflammation)
• Accumulation of fluid → pericardial effusion → risk of tamponade if large/rapid

Typical Presentation

• Chest pain: sharp, pleuritic, retrosternal or left precordial
  • Worse lying flat, on inspiration, coughing, swallowing
  • Relieved by sitting forward and leaning forward
• Fever (low-grade, especially viral)
• Preceding viral illness (1-2 weeks before) in many cases
• Dyspnoea (if significant effusion)

Examination Findings

• Pericardial friction rub: scratchy, high-pitched; best heard with diaphragm at left sternal edge, patient leaning forward in expiration
  • Classically has 3 components: atrial systole, ventricular systole, early diastole
  • May be intermittent
• Tachycardia
• Features of tamponade if large effusion (see Cardiac Tamponade)

Red Flags

• Haemodynamic compromise (tamponade)
• High fever (>38°C) with leucocytosis (suggests purulent pericarditis)
• Subacute onset (weeks) — consider TB or malignancy
• Immunosuppression
• On anticoagulants (risk of haemopericardium)
• Myopericarditis (troponin elevation — suggests myocardial involvement)
• Large pericardial effusion (>20 mm)
• Failure to respond to NSAIDs within 7 days

Bedside

• 12-lead ECG: widespread concave-upward (saddle-shaped) ST elevation in most leads; PR depression (especially lead II); reciprocal ST depression and PR elevation in aVR
  • Stage 1: diffuse ST elevation + PR depression
  • Stage 2: ST normalises, T-wave flattening
  • Stage 3: diffuse T-wave inversion
  • Stage 4: normalisation
• Observations: temperature, HR, BP, SpO₂

Bloods

• CRP/ESR: elevated (diagnostic criterion and guides duration of treatment)
• FBC: leucocytosis (may be normal in viral)
• Troponin: elevated in myopericarditis (~30%); indicates myocardial involvement
• U&Es: uraemia
• TFTs: hypothyroidism
• ANA, anti-dsDNA: if autoimmune cause suspected
• Blood cultures: if purulent pericarditis suspected

Imaging

• Echocardiography: pericardial effusion (may be absent in dry pericarditis); assess for tamponade features
• CXR: may be normal; enlarged cardiac silhouette if large effusion (flask-shaped heart)
• Cardiac MRI: confirms pericardial inflammation (late gadolinium enhancement of pericardium); differentiates from myocarditis
• CT chest: pericardial thickening, effusion, associated pathology

Special Tests

• Pericardiocentesis: if tamponade, suspected purulent/tuberculous pericarditis, or diagnostic uncertainty — send fluid for biochemistry, cytology, culture, PCR, adenosine deaminase (TB)

Non-pharmacological

• Exercise restriction: avoid strenuous physical activity until symptoms resolve and CRP normalises (typically 4-6 weeks for non-athletes; 3 months for athletes)
• Monitor for complications (effusion, tamponade)

Pharmacological

First-line (idiopathic/viral):

• Ibuprofen 600mg TDS for 1-2 weeks, then taper over 2-4 weeks
  • OR aspirin 750-1000mg TDS (preferred if concurrent ACS/post-MI)
• PLUS colchicine 500mcg BD (or 500mcg OD if <70 kg) for 3 months
  • COPE trial: colchicine halved recurrence rate
  • CORE trial: confirmed benefit in recurrent pericarditis
• PPI cover: with NSAID use (e.g., omeprazole 20mg OD)
• Avoid corticosteroids as first-line: associated with higher recurrence rate
• Corticosteroids reserved for: autoimmune/connective tissue disease, uraemic pericarditis, contraindications to NSAIDs/colchicine, pregnancy

Recurrent pericarditis:

• NSAIDs + colchicine (restart or extend)
• Low-dose corticosteroids: prednisolone 0.25-0.5 mg/kg/day with slow taper (months)
• Anakinra (IL-1 receptor antagonist) 100mg SC OD: for colchicine-resistant recurrent pericarditis (AIRTRIP trial)
• Azathioprine, IVIG: refractory cases

Specific causes:

• TB pericarditis: standard anti-TB therapy (RIPE) ± corticosteroids
• Purulent pericarditis: IV antibiotics + urgent pericardial drainage
• Uraemic: intensify dialysis

Surgical/Interventional

• Pericardiocentesis: therapeutic for tamponade; diagnostic for suspected TB/purulent/malignant
• Pericardiectomy: for refractory recurrent pericarditis or constrictive pericarditis

Referral Criteria

• High-risk features (fever, large effusion, tamponade, immunosuppression, troponin rise): hospital admission
• Low-risk idiopathic pericarditis: outpatient management with close follow-up
• Recurrent pericarditis: specialist referral

• Idiopathic/viral pericarditis: excellent prognosis; ~70-90% resolve within 1-2 weeks
• Recurrence: ~30% without colchicine; ~15% with colchicine
• Tamponade: rare in viral pericarditis (<5%); more common in purulent, malignant, or TB pericarditis
• Constrictive pericarditis: rare complication (~1% of idiopathic; higher with TB/purulent/radiation)
• Purulent pericarditis: mortality ~20-40% despite treatment
• Myopericarditis: generally good prognosis if LV function preserved; small risk of DCM

ECG Stages of Pericarditis

Pericarditis vs STEMI ECG