Autoimmune Autonomic Neuropathy

Autoimmune autonomic neuropathy (AAN) typically presents as a subacute panautonomic neuropathy with orthostatic hypotension (OH), gastrointestinal dysmotility, sicca complex, and anhidrosis. The most convincing evidence of an autoimmune pathogenesis is the demonstration of ganglionic nicotinic acetylcholine receptor (AChR) antibodies in high titer in about 50% patients. The antibody level correlates with the severity of dysautonomia. This observation suggests that some cases of AAN result from an antibody-mediated impairment of synaptic transmission in autonomic ganglia. The diagnosis of idiopathic AAN requires the demonstration of autonomic failure of subacute or acute onset and the exclusion of a toxic or paraneoplastic cause. Treatment for AAN has largely been symptomatic. On the basis of the evidence of an autoimmune pathogenesis, it is reasonable to consider plasma exchange or intravenous (IV) immunoglobulin. Single case reports of a successful IV immunoglobulin therapy have all involved early therapeutic intervention. However, it is yet to be determined whether this treatment is effective for patients with a chronic progressive or chronic stable course.