Studies evaluating the aetiology of acute pericarditis reported that a specific cause was found in 17% of patients and that most complications were seen in these patients [10]. Complications included acute cardiac tamponade (3.1%) and chronic constrictive pericarditis (1.5%).

Purulent pericarditis associated with tamponade is potentially fatal and requires urgent drainage and intravenous antibiotics; it carries a mortality rate of 40%.

Relapsing pericarditis occurs in 15-30% of patients with a presumed idiopathic aetiology, a small proportion of whom go on to suffer chronic relapsing pain.