Garland MM, Gutierrez A, Barratt DM. Peripheral neuropathy of the extremity after hyperbaric exposure. Aviat Space Environ Med 2012; 83:805–8.Background: Neurological deficits occurring after diving or hyperbaric exposure are typically due to central nervous system decompression illness (DCI). However, consideration of alternate diagnoses is sometimes warranted. Case Report: A 47-yr-old female hyperbaric technician developed foot drop 2 d following her last hyperbaric exposure. She had worked in chamber once daily at 45 fsw for 90 min. The breathing gas was air until the last 15 min, during which she breathed oxygen. Her history was complicated by a gastric bypass and weight loss totaling 160 pounds within the preceding 9 mo. She was treated for presumed neurological DCI without improvement. The adherence to safe hyperbaric protocols, delayed presentation, ongoing medical issues, and lack of response to therapy brought the diagnosis into question. Extensive neurological evaluation, including nerve conduction studies, revealed a common peroneal mononeuropathy. We concluded that her neuropathy was more likely due to extreme weight loss and malnutrition than peripheral nervous system DCI. Discussion: There are rare reports of DCI affecting the peripheral nerves of the extremities. A literature search revealed only three such cases. Two further reports describe peripheral neuropathy in the extremities of divers that were attributed to other causes: compression by a weight belt and vasculitis. However, peroneal neuropathy is one of the most common focal mononeuropathies of the lower extremity and has been reported in association with extreme weight loss and malnutrition. We attributed our diver’s neuropathy to extreme weight loss and malnutrition rather than DCI.