Phrenic nerve conduction in leprosy.

Phrenic nerve conduction was performed bilaterally in 22 multibacillary (BL-LL) and 18 paucibacillary (BT-TT) leprosy patients and 25 control subjects. Prolonged phrenic nerve conduction time and/or reduced amplitude of diaphragm muscle action potential beyond 2.5 standard deviations of control mean values was observed in 9 BL-LL patients (4 bilateral) and 6 BT-TT patients (all unilateral). Out of the nine BL-LL patients with phrenic nerve involvement, median motor and/or sensory nerve conduction was also abnormal in seven patients. On fluoroscopy, diaphragm movements were normal in all patients. The study documents subclinical phrenic nerve involvement in leprosy--a fact not previously recognized.