Case Report: Nitrofurantoin-induced interstitial lung disease

Nitrofurantoin is widely used for urinary tract infection (UTI) prophylaxis. Long-term use is known to be able to cause serious adverse effects including pulmonary and hepatic toxicity. The prevalence of nitrofurantoin-induced pulmonary injury is on the increase again as the drug regains popularity as a urinary antiseptic. We describe a previously healthy 83-year-old woman who presented to our emergency department in early 2012 with progressive dyspnoea since two weeks. This was not preceded by cough. She had no fever, wheezing, chest pain, or sputum production. She was a 50 pack per year ex-smoker. She had no previous exposure to tuberculosis or industrial chemicals. However, she suffered from recurrent symptomatic UTIs and was on a long-term prescription of nitrofurantoin for prophylaxis. Respiratory examination revealed dullness on percussion at both lung bases and widespread fine inspiratory crackles throughout both lungs. Arterial blood gas analysis showed hypoxia and complete compensation of respiratory acidosis. Initial treatment with co-amoxiclavulanic acid was initiated. CT scanning of the chest showed widespread ground-glass appearance in both lungs with organising pneumonia. A diagnosis of nitrofurantoin-induced interstitial lung disease (NIILD) was suspected. Nitrofurantoin was subsequently stopped and prednisone treatment at 30 mg OD was initiated. Follow-up chest X-ray showed marked improvement.