Autonomic nervous system dysfunction and impotence in uremia.

The relationship between abnormalities in nocturnal penile tumescence (NPT) and autonomic function, measured by the Valsalva maneuver, was evaluated in 25 uremic patients and 22 normal subjects. NPT in uremic patients (45 +/- 6.8 min/night) was lower (p less than 0.01) than in normals (85 +/- 10.4 min/night). Valsalva ratio in uremics (1.58 +/- 0.07) was also lower (p less than 0.01) than in normal subjects (2.05 +/- 0.11). NPT and Valsalva ratio were significantly correlated in uremic patients (r = 0.62, p less than 0.01). The 12 uremic patients with abnormal Valsalva maneuver had NPT of 22 +/- 5.2 min/night, a value lower (p less than 0.01) than that (67 +/- 8.7 min/night) observed in the 13 uremic patients with normal Valsalva maneuver. There was also a significant correlation (r = 0.56, p less than 0.05) between the Valsalva ratio and the frequency of intercourse per month in the uremic patients, who had steady and active sexual partners. The data suggest that a dysfunction of the autonomic nervous system may be an important factor in the genesis of erectile abnormalities in patients with uremia.