Wide range of clinicopathological features in immune‐mediated autonomic neuropathies

Autonomic neuropathies can occur primarily or secondarily to various underlying diseases. The clinical features of autonomic neuropathies vary with the severity and the modality of autonomic dysfunctions, the degree of somatic involvement, the presence or absence of anti‐ganglionic acetylcholine receptor antibody and the extent of unmyelinated fiber loss. Primary autonomic neuropathies, which usually affect both cholinergic and adrenergic functions, are divided into autoimmune autonomic ganglionopathy, acute autonomic and sensory neuropathy, and acute autonomic sensory and motor neuropathy based on the concomitance or absence of sensory or motor dysfunctions (although the nosological relationship of acute autonomic sensory and motor neuropathy to G uillain– B arré syndrome should be carefully considered). The monophasic clinical course and frequent presence of a history of antecedent infections suggests that immune mechanisms participate in these neuropathies. The discovery of the anti‐ganglionic acetylcholine receptor antibody significantly expanded the spectrum of autonomic neuropathies, especially autoimmune autonomic ganglionopathy, to include cases with chronic progression mimicking pure autonomic failure. Patients with primary autonomic neuropathies might manifest restricted forms of autonomic dysfunctions, such as cholinergic dysautonomia, postural orthostatic tachycardia syndrome, chronic intestinal pseudo‐obstruction or acquired idiopathic generalized anhidrosis. Some immunological diseases, such as paraneoplastic syndrome, connective tissue diseases and celiac disease, might also cause diverse autonomic neuropathies. As many non‐immunological diseases are known to cause various types of autonomic dysfunctions, excluding such diseases is important for the diagnosis of immune‐mediated autonomic neuropathies.