Pericardial effusion

The amount of fluid may range in volume from a few millilitres up to 2 litres. It may be a transudate (hydropericardium), exudate (pyopericardium) or haemopericardium.

• Large effusions are common with neoplastic, tuberculous, uraemic pericarditis, myxoedema and parasitic infections.

• Loculated effusions are more common when scarring is present - eg, post-surgery, post-trauma, post-purulent pericarditis.

• Massive chronic pericardial effusions are rare and make up only 2-3.5% of all large effusions.

Pericardial effusion (epidemiology)¹

• Small pericardial effusions are often asymptomatic and pericardial effusion has been found in 3.4% of general autopsy studies.¹

• Studies in the pre-highly active antiretroviral therapy (HAART) era reported an incidence of 11% of pericardial effusion in HIV patients. However, post-HAART the incidence is much reduced (only 2 patients in a cohort of 802 in one study).²

• 10.7% of autopsies of cancer patients show pericardial effusion.

What causes pericardial effusion (aetiology)

There are many causes of a pericardial effusion which may be either local, as in acute pericarditis or chronic pericarditis, or systemic. Among the causes of pericardial effusion are:

• Idiopathic.

• Infectious pericarditis: viral - eg, HIV, tuberculosis (TB), fungi, parasites, syphilis, bacterial.

• Acute myocardial infarction.

• Acute kidney injury or chronic kidney disease.

• Malignancy (both primary and secondary): may develop from direct extension or metastatic spread of the underlying malignancy, from an opportunistic infection, or from a complication of radiotherapy or chemotherapy.³

• Benign tumours.

• Hypothyroidism.

• Trauma.

• Familial Mediterranean fever.

• Whipple's disease.

• Ruptured aortic aneurysm with leakage into the pericardial sac.

• Severe chronic anaemia.

• Sarcoidosis.

• Post-radiotherapy.

• Post-cardiac surgery:⁴
  

  • After open-heart surgery, a localised effusion at the posterior wall can be found, with complete compression of the right atrium.

  • This leads to cardiac tamponade.

  • This may be misinterpreted as atrial myxoma or other cardiac tumour.

• Autoimmune diseases: systemic lupus erythematosus, rheumatoid arthritis, ankylosing spondylitis, acute rheumatic fever, granulomatosis with polyangiitis, scleroderma.

• Drug-induced - eg, hydralazine, isoniazid, minoxidil, phenytoin, anticoagulants, methysergide.

Pericardial effusion symptoms

The symptoms produced by a pericardial effusion depend on the speed with which the effusion is formed, as well as the size of the effusion. Many small-to-moderate effusions formed over a long period of time will be relatively asymptomatic.⁵ However, even small effusions which have occurred rapidly may compromise the circulation and cause tamponade.⁶

Symptoms

• Chest pain, pressure, discomfort: pericardial pain may be relieved by sitting up and leaning forward and is intensified by lying supine.

• Light-headedness, syncope.

• Palpitations.

• Cough, shortness of breath, hoarseness.

• Anxiety and confusion.

• Hiccoughs.

Signs

• Classic triad of pericardial tamponade: hypotension, muffled heart sounds, jugular venous distention.

• Pulsus paradoxus: exaggeration of the normal respiratory variation in systemic blood pressure (defined as a decrease in systolic blood pressure of more than 10 mm Hg with inspiration). A pulsus paradoxus in patients with a pericardial effusion helps distinguish those with cardiac tamponade from those without.⁷

• Pericardial friction rub: the most important physical sign of acute pericarditis. High-pitched and most often heard during expiration with the patient upright and leaning forward.

• Tachycardia.

• The heart may move within the pericardial cavity ('swinging heart') where there is a large pericardial effusion. This unusual motion of the heart creates 'pseudo' conditions like pseudomitral valve prolapse, pseudosystolic anterior motion of the mitral valve, paradoxical motion of the interventricular septum and midsystolic aortic valve closure.⁸

• Respiratory signs include tachypnoea, decreased breath sounds and Ewart's sign (dullness to percussion beneath the angle of the left scapula due to compression of the left lung by pericardial fluid).

• Other signs include hepatosplenomegaly, weakened peripheral pulses, oedema and cyanosis.

Differential diagnosis

Differential diagnosis will include the causes of right and left heart failure including:

• Cardiac tamponade.

• Pulmonary embolus.

• Constrictive pericarditis.

• Ventricular aneurysm.

• Myocardial infarction.

• Cardiomyopathy.

Investigations

• FBC (white cell count raised, or cytopenia as a sign of underlying disease - eg, cancer or HIV).

• Renal function tests and electrolytes (uraemia may be present).

• TFTs: TSH.

• Cardiac enzymes (troponin level is often minimally elevated in acute pericarditis).

• Auto-antibodies - eg, rheumatoid factor, antinuclear antibody.

• Blood cultures.

• Elevated carcinoembryonic antigen (CEA) levels in pericardial fluid have a high specificity for malignant effusion.

• Echocardiogram:
  

  • Transoesophageal echocardiography is particularly useful in postoperative loculated pericardial effusion, or in identifying metastases and pericardial thickening.

• CXR:
  

  • May show increased cardiothoracic ratio.

  • Large effusions are depicted as globular cardiomegaly with sharp margins.

  • On well-penetrated lateral films, pericardial fluid is suggested by lucent lines within the cardiopericardial shadow.

• ECG:
  

  • May show raised ST segments with myocardial infarction or pericarditis.

  • There may also be diminished QRS and T-wave voltages, PR-segment depression, ST-T changes, bundle branch block and electrical alternans.

• Pericardial fluid aspiration for analysis:
  

  • Protein level, cell count, culture.

  • Smear for acid-fast bacilli in suspected TB infection, especially in patients with HIV.

• MRI/CT scan:
  

  • MRI can detect as little as 30 ml of pericardial fluid.

  • Both MRI and CT scan may be superior to echocardiography in detecting loculated pericardial effusions and pericardial thickening.

• Pericardioscopy and pericardial biopsy, especially if malignant pericardial effusion is suspected.⁹

Pericardial effusion treatment and management

Pericardial effusions can occur in the absence of cardiac tamponade. However, nearly one third of patients with large idiopathic pericardial effusions develop cardiac tamponade unexpectedly. Some authorities recommend that large pericardial effusions be drained if the effusion persists for more than a month or if there is right-sided heart collapse. If smaller pericardial effusions recur and the patient remains asymptomatic without haemodynamic compromise, regular follow-up with clinical examination and/or echocardiography is recommended.⁷

Pharmacological

Oxygen therapy will help to relieve symptoms in patients whose circulation is compromised by a pericardial effusion.

• Treatment of the underlying condition - eg, with cytotoxic agents for malignancy, or steroids and non-steroidal agents for rheumatoid arthritis, will help to reduce the volume of fluid in the pericardial sac.

• Patients with dehydration and hypovolaemia may temporarily improve with intravenous fluids improving ventricular filling.

Surgical

• Pericardiocentesis may be used to reduce the volume of fluid in the pericardial sac:⁸
  

  • It may not be necessary when the diagnosis can be made based on other systemic features, or the effusions are very small or resolving under anti-inflammatory treatment.

  • Pericardiocentesis is contra-indicated in wounds, ruptured ventricular aneurysm, or dissecting aortic haematoma.

  • Needle evacuation is impossible and surgical drainage is mandatory.

• A surgical approach is recommended only in patients with very large chronic effusion, for whom repeated pericardiocenteses have been unsuccessful:
  

  • Subxiphoid pericardial window creation with pericardiostomy is used as an alternative to pericardiocentesis in some centres:
    

    • This procedure is associated with low morbidity, mortality and recurrence rates and it can be performed under local anaesthesia.

    • However, it may be less effective when effusion is loculated.

    • Studies found no difference in mortality between the two procedures. Pericardiotomy may produce more procedural complications, whilst pericardiocentesis may be associated with a higher recurrence rate.¹⁰

    • Pericardiotomy has a higher success rate in preventing recurrence in malignant pericardial effusion than pericardiocentesis.¹¹

  • In patients with persistent effusions, a pleuropericardial window may be created, either by means of video-assisted thoracic surgery (VATS) or a thoracotomy:
    

    • The pleuropericardial window will allow for drainage of the fluid into the pleura from where it is more easily reabsorbed.

    • It allows resection of a wider area of pericardium than the subxiphoid approach. It also allows the surgeon to deal with any concomitant pleural pathology.

    • However, it does require general anaesthesia with single lung ventilation

  • If the effusion recurs, balloon pericardotomy may also be considered:
    

    • A catheter is placed in the pericardial space under fluoroscopy which, after inflation of the balloon, creates a channel for passage of fluid into the pleural space, where reabsorption occurs more readily.

    • This may be useful for recurrent effusions

  • An alternative is pericardial sclerosis:
    

    • Several sclerosing agents have been used with differing success rates - eg, tetracycline, doxycycline, cisplatin and 5-fluorouracil.

    • The catheter may be left in place for repeat instillation, if necessary, until the effusion resolves.

    • Complications include severe pain, fever, infection and atrial dysrhythmias.

    • Success rates are reported as >90% at 30 days.¹²

  • Resistant neoplastic processes may require intrapericardial treatment.

Complications

• Pericardial tamponade. This can lead to severe haemodynamic compromise and death.

• Chronic pericardial effusion. These are effusions lasting longer than six months and they are usually well tolerated.

Prognosis

• The prognosis for a patient with a pericardial effusion will depend on the underlying cause. Large effusions generally indicate more serious disease.

• If the precipitating cause is not life-threatening, small, chronic effusions are usually well tolerated.