Autoimmune Autonomic Neuropathy

Autoimmune autonomic neuropathy (AAN) presents as unexplained autonomic failure with orthostatic hypotension, gastrointestinal dysmotility, sicca, anhidrosis, and pupil abnormalities. The autonomic deficits may be monophasic with incomplete recovery or chronic and persistent. Paraneoplastic autonomic neuropathy can present in a similar fashion. Ganglionic acetylcholine receptor antibodies are frequently (but not always) found in patients with AAN. The level of this antibody correlates with the severity of autonomic deficits. Plasma exchange and intravenous immunoglobulin are anecdotally effective and may be considered for severe cases of recent onset. Studies in animal models indicate that AAN is caused by antibody-mediated impairment in synaptic transmission in autonomic ganglia. .