Uraemic Pericarditis

Uraemic pericarditis is inflammation of the pericardium in patients with severe kidney failure. Two entities exist. True uraemic pericarditis occurs in untreated or inadequately dialysed patients, typically with urea above 60 mmol/L, and responds to dialysis. Dialysis associated pericarditis occurs in patients on adequate dialysis, often with volume overload, infection or missed sessions.

Frequency has fallen from about 40% to under 5% since dialysis became widely available. The pericardium shows fibrinous, haemorrhagic inflammation of both visceral and parietal layers. Effusions may be large and haemorrhagic, and tamponade is the major hazard.

Differences between forms. Uraemic pericarditis improves with intensified dialysis; dialysis pericarditis may need drainage. Pericardial fluid is exudative and often blood stained.

• Pleuritic precordial chest pain relieved by sitting forward (may be absent), fever (uncommon in uraemic pericarditis; present in infection), dyspnoea, cough.
• Pericardial friction rub (one to three components) loudest at the left sternal edge, may be transient.
• Tamponade: hypotension (especially intradialytic hypotension), tachycardia, raised jugular venous pressure with absent y descent, pulsus paradoxus (inspiratory fall in systolic pressure above 10 mmHg), muffled heart sounds, narrow pulse pressure, oliguria.
• ECG: diffuse ST elevation is often absent in uraemic pericarditis because inflammation spares the myocardium; electrical alternans with large effusions.

Red flags

• Hypotension, tachycardia, pulsus paradoxus or raised venous pressure: tamponade.
• Fever above 38°C and rising CRP: infective pericarditis.
• Haemorrhagic effusion on anticoagulation, or recent heparin based dialysis.
• Failure to improve after 7 to 14 days of daily dialysis.

• Echocardiogram: size of effusion (small under 10 mm, moderate 10 to 20 mm, large above 20 mm), right atrial and ventricular diastolic collapse, respiratory variation of mitral and tricuspid inflow (greater than 25% and 40% respectively), dilated inferior vena cava.
• ECG, chest radiograph (globular heart), troponin (mild rise), CRP, urea (usually above 60 mmol/L in true uraemic pericarditis), blood cultures if febrile.
• CT or cardiac MRI for loculated effusion, thickening or constriction.
• Pericardial fluid (when drained): cell count, protein, culture, acid fast bacilli and cytology.

Differential diagnosis

• Viral or idiopathic pericarditis, tuberculous, bacterial, myocardial infarction, malignancy, systemic lupus erythematosus and other autoimmune disease, drug induced (hydralazine, minoxidil, isoniazid), radiation, hypothyroidism, constrictive pericarditis, heart failure with effusion.

First line: intensify dialysis

• Daily haemodialysis for 7 to 14 days, 3 to 4 hours each session, with heparin free or minimal heparin technique (saline flushes 100 mL every 30 minutes) to prevent haemopericardium. Avoid excessive ultrafiltration, because hypovolaemia can precipitate tamponade; ultrafiltrate to dry weight cautiously.
• Peritoneal dialysis patients: transfer to haemodialysis temporarily.
• Correct volume overload, anaemia, hypoalbuminaemia, acidosis and hyperkalaemia.

Analgesia

• Paracetamol 1 g four times daily (maximum 4 g daily). NSAIDs: avoid in patients with residual kidney function; indometacin 25 mg three times daily has been used in dialysis patients for short courses (3 to 5 days) with gastric protection. Colchicine is avoided when eGFR is under 30. Systemic glucocorticoids (prednisolone 1 mg/kg daily for 1 to 2 weeks, then taper) are used for refractory disease after infection is excluded.

Pericardial drainage

• Indicated for tamponade (emergency), large effusions (above 20 mm) persisting after 7 to 14 days of intensive dialysis, purulent pericarditis, or suspected malignancy or tuberculosis.
• Emergency pericardiocentesis under echocardiographic control for tamponade; give 250 mL of 0.9% sodium chloride while preparing, avoid diuretics and vasodilators, and avoid ultrafiltration.
• Prolonged catheter drainage (2 to 3 days) with intrapericardial triamcinolone 50 mg every 6 hours for 2 to 3 days. Subxiphoid pericardial window or video assisted thoracoscopic window for recurrent effusion; pericardiectomy for constriction.

Monitoring. Echocardiography at 1 week, then at 4 to 6 weeks, to document resolution; watch for constriction at 6 to 12 months.

Referral and escalation. Immediate cardiology and critical care for tamponade; cardiothoracic surgery for recurrent or loculated effusion or constriction; nephrology to adjust dialysis dose.

Special groups

• Patients on anticoagulation: stop and reverse if tamponade (vitamin K and prothrombin complex concentrate).
• Transplant recipients: consider infection, mycophenolate and other immunosuppression related causes.
• Pregnancy: intensified dialysis and echocardiographic follow up.