Peripheral nerve dysfunction in adult patients with cystic fibrosis.

The prevalence of peripheral nerve dysfunction was assessed in 24 randomly selected adult patients with cystic fibrosis. Median, peroneal and sural nerves were studied. In 15 patients (62%), one or more electrical abnormality were detected. In the median nerve, conduction velocity was slowed in 29% of sensory studies and 12.5% of motor studies; compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes were normal. The CAMP was low in 17% of peroneal studies with motor conduction velocity slow in 8%. The sural SNAP was low in 17% and sensory nerve conduction velocity slow in 25%. Using a multiple regression analysis only age at diagnosis was identified as a significant predictor of peripheral nerve dysfunction (multiple R = 0.55; p < 0.01). This study demonstrates that mild peripheral nerve dysfunction is common in patients with cystic fibrosis. With the improving long term survival of these patients we predict that the prevalence and severity of this complication will increase.