Severe thrombocytopenia secondary to asymptomatic cytomegalovirus infection in an immunocompetent host

A healthy 33 year old man presented with a short history of purpura and easy bruising. Investigations showed profound thrombocytopenia with atypical lymphocytes in the peripheral blood. Marrow appearances were consistent with platelet consumption. Biochemical hepatitis was also noted. An infection screen showed the underlying diagnosis to be cytomegalovirus (CMV) infection. He was treated successfully with oral prednisolone. This subsequently tailed off without relapse. Careful examination of a stained blood film is needed in all cases of apparent idiopathic immune thrombocytopenic purpura.