Benzylpenicillin-induced leucopenia. Complication of treatment of bacterial endocarditis.

In the majority of cases of bacterial endocarditis the causal organism is sensitive to benzylpenicillin (Finland and Barnes, I970). Thus this antibiotic is widely used in the treatment of endocarditis and its curative value and low toxicity are well proved. It is common for benzylpenicillin to be given in large doses by the intravenous route for a period of weeks to ensure eradication of the infection. Toxic effects of benzylpenicillin are rare and mainly confined to the central nervous system, but hypersensitivity is more common, ranging from a mild urticarial reaction to fatal anaphylaxis. Haematological manifestations of hypersensitivity to penicillin G are rare though a haemolytic anaemia with positive Coombs test has been reported with high dosage intravenous therapy (Petz and Fudenberg, 1966; White et al., I968) and intramuscular treatment (Rossiter, Gray, and Shinton, I968). Leucopenia is another rare manifestation of hypersensitivity, only five cases having previously been recorded.