Most cases arise when an amebic abscess in the liver (usually the left lobe, occasionally the right lobe) ruptures into the pericardium. Occasionally the preceding lesion is an amebic abscess in the lung or pleura.
Clinical features:
(1) Some patients develop a slowly progressive pericardial effusion with friction rub, fever, dyspnea and chest pain.
(2) Some patients have a rapid onset of cardiac tamponade with chest pain and shock.
(3) The patient usually develops ECG changes of pericarditis.
Demonstration of an abscess in the liver on imaging studies can be a helpful finding in making the diagnosis.
Laboratory testing should include:
(1) examination of pericardial fluid for trophozoites
(2) serum antibody (but this may be nonspecific in an endemic area)
(3) antigen detection in serum and pericardial fluid
(4) stool studies for ova and parasites (but this may be negative)
(5) PCR on pericardial fluid
Complications may include:
(1) constrictive pericarditis
(2) secondary bacterial infection
(3) pericardial rupture
(4) mediastinitis
Differential diagnosis:
(1) hepatic bacterial abscess
(2) tuberculous pericarditis
