The causes of acute pericarditis are widespread and are listed in Table 1:

Table 1: Causes of acute pericarditis (this is not exhaustive)
Idiopathic Most likely to be viral in origin
Viral e.g.
CMV (immunocompromised patients)
Hep B
Infectious mononucleosis
Bacterial e.g.
Characterised by purulent effusion. Commonest cause is by direct extension from a pneumonia or empyema
Tuberculous 1-8% of patients with pulmonary TB.
Characterised by a more indolent course and non-specific features of fever, malaise and dyspnoea [5]
Post Acute Myocardial Infarction Early (1-3 days): transmural necrosis causing adjacent pericarditis
Late (1 week to a few months): Dressler’s Syndrome (autoimmune)
Trauma / Post Cardiac Surgery Blunt or penetrating injury
Neoplastic Predominantly from secondary metastatic tumours
Uraemia Pathophysiology unknown
Inflammatory/ Autoimmune Rheumatoid arthritis
SLE: the most common cardiac manifestation (40 % patients with SLE get pericarditis at some time5) Scleroderma
Following chest wall irradiation Early: acute illness
Late: can occur years after exposure
Drug induced Isoniazid

Most cases are ‘idiopathic’ (80-90%) [5]. Although labelled as idiopathic, the majority of these are likely to be viral in origin, but viral testing is not routinely done as it rarely alters the management and is not cost-effective.

The incidence of viral pericarditis is higher in young previously healthy adults and is lower in those patients who are subsequently found to need inpatient management. Patients with tuberculous pericarditis present with a less acute course. Patients with bacterial pericarditis present more acutely unwell and with other features of bacterial sepsis.

Learning bite

Most cases of acute pericarditis in developed countries are based on viral infections which are self-limiting, with most patient recovering without complications.