Acute pandysautonomic neuropathy is characterized by severe postganglionic sympathetic and parasympathetic dysfunction, with relative or complete sparing of motor and sensory function. Of four reported cases with sural nerve biopsies, two were normal and two abnormal, revealing loss of small myelinated and unmyelinated fibers. We present a patient with pandysautonomic neuropathy and elevated CSF protein whose sural nerve biopsy showed active axonal degeneration.