Antithyroid-drug-induced agranulocytosis complicated by life-threatening infections

Agranulocytosis is a rare complication of antithyroid drugs, and the aetiol ogies of community-acquired, rife-threatening infections in patients taking these drugs have not previously been systematically described. Of 5653 hyp erthyroid patients treated with antithyroid drugs at National Taiwan Univer sity Hospital between January 1987 and December 1997, 13 (0.23%) developed agranulocytosis with life-threatening infections. The most common presentat ions were fever (92%) and sore throat (85%). Initial clinical diagnoses wer e acute pharyngitis (46%), acute tonsillitis (38%), pneumonia (15%) and uri nary tract infection (8%). Positive blood cultures from six patients yielde d Pseudomonas aeruginosa (3), Escherichia coli (1), Staphylococcus aureus ( 1), Capnocytophaga species (1). Two patients died of uncontrolled infection , thyroid storm and multiple organ failure. Cases of antithyroid-drug-induc ed agranulocytosis in the English language literature are reviewed; Gram-ne gative bacilli, including Klebsiella pneumoniae (4 patients) and P. aerugin osa (3), were the most common pathogens in clinical isolates. Our observati on and review suggest that broad-spectrum antibiotics with antipseudomonal activity should be given to patients with antithyroid drug-induced agranulo cytosis who present with severe infection.