Dysautonomia in immune-mediated neuropathies

In Guillain-Barre syndrome (GBS), severe dysautonomia is associated with a poor prognosis and may cause extraperipheral nervous system disorders such as posterior reversible encephalopathy syndrome and Takotsubo cardiomyopathy. Dysautonomia is associated with demyelination in vagal nerves with mononuclear cell infiltration, and demyelination is the predominant pathology. Approximately half of the cases of autoimmune autonomic ganglionopathy (AAG) are positive for antiganglionic acetylcholine receptor antibody. It is believed that there is no clinical difference between antibody-positive and antibody-negative cases, but a recent study indicated that seronegative AAG is a distinct clinical entity. Extra-autonomic symptoms such as central nervous system disorder, amenorrhea, and syndrome of inappropriate secretion of antidiuretic hormone are also present in AAG. When accompanied by sensory impairment, it is difficult to distinguish AAG from acute autonomic sensory neuropathy (AASN). It is also often difficult to distinguish AASN from GBS, as two-thirds of patients with AASN have antecedent infection, AASN often has a monophasic course, and there are also antiglycolipid antibody-positive cases. Identification of biomarkers is required for evaluation of the pathophysiology of AASN and establishment of diagnostic criteria. There is an urgent need for biomarkers and for definition of highly sensitive diagnostic criteria for immune-mediated dysautonomia.