Giant cell interstitial pneumonia associated with nitrofurantoin.

A case of giant cell interstitial pneumonia (GIF) that occurred in association with exposure to nitrofurantoin is presented. While the diagnosis of GIP is confirmed by histopathology, this diagnosis can be supported by the findings of bizarre multinucleated giant cells (MGC), elevated T lymphocytes, and a low T lymphocyte helper/suppressor ratio in the bronchoalveolar lavage fluid (BALF). Recognition of GIP as a rare manifestation of nitrofurantoin toxicity is important because prompt therapy may be associated with a favorable outcome.