Immune-mediated autonomic neuropathies.

Improved recognition and availability of noninvasive testing of autonomic disorders has prompted a better understanding of disease mechanisms of some disease forms, especially potentially treatable immune-mediated autonomic neuropathies. Development is acute, subacute, or less commonly chronic. Autonomic involvement is common and an important cause of morbidity and mortality in Guillain-Barré syndrome. Acute autonomic neuropathy can affect parasympathetic, sympathetic, and enteric nerves or neurons and is associated with antibodies to ganglionic nicotinic acetylcholine receptors. These antibodies appear to be causative based on a rabbit immunization model and serum transfer studies from patients and animals. Other important immune autonomic disorders discussed include Lambert-Eaton myasthenic syndrome, some forms of orthostatic intolerance, chronic autonomic neuropathy, and Sjögren syndrome. Paraneoplastic autonomic disorders are clinically indistinguishable and associated with various overlapping antibody associations, including anti-Hu (ANNA-1), ganglionic acetylcholine receptors, CRMP-5, and PCA-2.