Probable nitrofurantoin-induced bronchiolitis obliterans with organizing pneumonia.

Purpose: A case of bronchiolitis obliterans with organizing pneumonia (BOOP) that developed after three years of nitrofurantoin therapy is described.

Summary: An 89 year-old Caucasian woman weighing 60 kg with diastolic heart failure and a history of urosepsis, viral pericarditis, and atrial fibrillation arrived at the emergency department with worsening dyspnea, shortness of breath that had limited her activities of daily living for three days, and lower extremity edema. Over the previous six months the patient had experienced decreased appetite, abdominal bloating, and a 9.1-kg weight loss. Four months prior, the primary physician diagnosed her symptoms of worsening dyspnea at rest and with exertion as severe bronchitis. Imaging at the time of presentation revealed interstitial fibrosis consistent with nitrofurantoin-induced BOOP. A diagnosis of BOOP was made, nitrofurantoin was discontinued, and the patient was discharged home on oxygen. Prednisone 20 mg was started two weeks later, after no improvement in symptoms was seen. Seven weeks after nitrofurantoin discontinuation, the results of a chest radiograph and computed tomography scan were unchanged, but her symptoms had improved by 20%. The patient was readmitted three weeks later for worsening dyspnea, and it was determined that prednisone had resulted in fluid retention, complicating her diastolic congestive heart failure. Prednisone therapy was therefore tapered off after two months of treatment. No improvement in subjective symptoms, in chest radiograph results, or in BOOP symptoms was seen after three months of prednisone discontinuation and five months of nitrofurantoin discontinuation.

Conclusion: An 89-year-old woman developed unresolving BOOP after three years of nitrofurantoin therapy.