Agranulocytosis in a drug addict with recurrent Staphylococcus aureus septicaemia.

Accepted 1 June 1995 A 37-year-old male drug addict was admitted to hospital because of a swollen right lower limb for two weeks. He had been using his groin for injection of heroin. He had been hospitalised three times six months earlier because of left lower limb deep vein thrombosis with or without Staphylococcus aureus septicaemia. He discharged himselfprematurely during the first admission. Apart from anticoagulants, he received intravenous cloxacillin, 500 mg 6-hourly, up to a total dose of 8.5-15.0 g during two of these admissions. Neutropenia was not seen. He had subsequently defaulted from follow-up. On admission, he was febrile, with a blood pressure of 120/84 mmHg and a heart rate of 100 beats/min. No cardiac murmurs were detected on auscultation of the precordium. No stigmata of infective endocarditis such as splinter haemorrhages were detected. His right lower limb looked swollen, with increased warmth and dilated superficial veins. Doppler ultrasound examination revealed a thrombus in his right femoral vein, which was treated by an intravenous heparin infusion, followed by warfarin. Blood cultures taken on admission grew S aureus, which was sensitive to cloxacillin. From day 2, he was put on intravenous cloxacillin, 1 g, 6-hourly together with netilmicin, 120 mg, 12-hourly. The dosage of cloxacillin was increased to 2 g 4-hourly on day 9 because ofthe poor clinical response. Although no vegetations were revealed on echocardiography, antibiotic therapy for four or more weeks was considered necessary in view of the history of recurrent septicaemia. His condition continued to improve until day 19 by which time he had received a total dose of 165 g of cloxacillin. He was then noted to have a high fever (figure) and a generalised maculopapular rash. His white cell count was 7.0 x 109/1 (63% neutrophils) on day 20 but had dropped to 1.7 x 109/1 (1% neutrophils) by day 22 (figure). There were no significant changes in red cell or platelet counts. When both antibiotics were stopped on day 23, the fever rapidly subsided and the agranulocytosis gradually resolved. By day 25, his white cell count was 2.6 x 109/1 (neutrophils 29%) and by day 27, the agranulocytosis had completely resolved.