Interstitial pneumonitis probably induced by cyclophosphamide in nephrosis

A case of interstitial shadows associated with oral cyclophosphamide therapy in a 32-month-old girl with steroid-resistant nephrotic syndrome, who was admitted to the Nishi-Kobe Medical Center with systemic edema, is reported. Due to the lack of response to prednisolone, cyclophosphamide was also administered orally at a dose of 3 mg/kg per day, 4 weeks after the start of steroid therapy. Approximately 3 weeks after the combination treatment she developed a fever, dry cough and cyanosis. Radiographic examination showed diffuse ground-glass shadow in both lungs, presumably indicating that she had interstitial pneumonitis. Her pulmonary signs and symptoms deteriorated despite various antimicrobial treatments. A discontinuation of cyclophosphamide and the administration of high-dose methylprednisolone yielded a dramatic improvement. These findings suggest that the diffuse pulmonary disease in this case was induced by cyclophosphamide. Since interstitial pneumonitis may be fatal and irreversible, attention should be paid to this rare complication even in patients undergoing low-dose oral cyclophosphamide treatment.