Acute panautonomic neuropathy.

Two patients with acute panautonomic neuropathy had severe impairment of sympathetic and parasympathetic function of acute onset. Autonomic tests suggesting a postganglionic lesion and direct evidence of loss of unmyelinated and small myelinated fibers on nerve biopsy were found in Patient 1. There was a selective loss of small myelinated and unmyelinated nerve fibers; C potential was absent in the in vitro compound action potential; dopamine-beta-hydroxylase activity was unmeasurable. No definite abnormalities were found on the nerve biopsy of Patient 2. The acute panautonomic neuropathies appear to comprise a spectrum of somatic and autonomic involvement.