Nitrofurantoin-associated Acute Pulmonary Toxicity Mimicking Severe Sepsis with Significantly Elevated Procalcitonin.

Nitrofurantoin is a commonly used treatment for urinary tract infections with a risk for pulmonary toxicity. We report a case of a 48-year-old woman on a prophylactic regimen of nitrofurantoin who exhibited classic signs of bacterial sepsis including elevated procalcitonin (PCL) and C-reactive protein (CRP) levels two days post-nephrolithotripsy. The microbial analysis did not reveal an infectious cause for the initial symptoms and, subsequently, the patient developed a dry cough, fever, chills, and transient hypoxemia requiring supplemental oxygen. Pulmonary imaging revealed significant abnormal features inconsistent with the patient's symptoms which indicated an inflammatory/immune reaction to nitrofurantoin. Treatment discontinuation improved the patient's symptoms and reduced PCL and CRP levels to within normal limits. A high index of suspicion for nitrofurantoin-associated pulmonary toxicity is warranted for patients on a regimen of nitrofurantoin who exhibit severe pulmonary symptoms and elevated PCL and CRP levels with no corresponding infection.