Abstract

Although autonomic neuropathy may occur as a secondary consequence of various diseases, other patients without any obvious underlying diseases show profound autonomic dysfunctions from the early phase of the disease. These idiopathic or primary cases are divided into pure autonomic neuropathy, autonomic neuropathy with sensory impairment, and autonomic neuropathy with sensory and motor impairment based on the concomitance or absence of sensory or motor dysfunctions. The discovery of the antiganglionic acetylcholine receptor antibody suggested the involvement of immune mechanisms in idiopathic cases, especially in those cases with pure autonomic neuropathy. The ability to test for the presence of this antibody has significantly expanded the concept of autonomic neuropathy to include cases with a chronic progressive course that mimics pure autonomic failure. Recent work based on the antiganglionic acetylcholine receptor antibody has established autoimmune autonomic ganglionopathy as an isolated nosological entity. Other forms of primary autonomic neuropathies include acute autonomic and sensory neuropathy and acute autonomic sensory and motor neuropathy, although the nosological relationship of the latter to Guillain–Barré syndrome should be discussed. Although the possibility of infectious, metabolic or toxic aetiologies should be carefully excluded in these forms of autonomic neuropathy, the monophasic clinical course and the presence of antecedent infections suggest the involvement of immune mechanisms similar to Guillain–Barré syndrome. Neuronopathy in the autonomic ganglia is considered to be a common pathology in these autonomic neuropathies. In addition, clinically significant autonomic neuropathy may be associated with pre-existing immunological diseases such as paraneoplastic syndrome and Sjögren's syndrome. An overlap with autoimmune autonomic ganglionopathy has been suggested in these settings.