Seronegative autoimmune autonomic neuropathy: a distinct clinical entity.

Purpose: Autoimmune autonomic ganglionopathy (AAG) is associated with ganglionic acetylcholine receptor (gAChR) antibodies. We describe a similar but distinct series of patients with autoimmune autonomic failure lacking this antibody.

Methods: Retrospective chart review.

Results: Six patients presented with subacute autonomic failure, seronegative for gAChR antibodies. Orthostatic hypotension and gastrointestinal complaints were common. Autonomic testing revealed predominant sympathetic failure and no premature pupillary redilation. All patients had sensory symptoms and/or pain, which was severe in three. Immunotherapy with plasma exchange, intravenous immunoglobulin, and rituximab was ineffective. Three patients responded to intravenous steroids.

Conclusion: In these cases of autoimmune autonomic failure, key differences from seropositive AAG emerge. Testing showed prominent sympathetic (rather than cholinergic) failure, specific pupillary findings of AAG were absent, and sensory symptoms were prominent. AAG responds to antibody-targeted immunotherapy, while these patients responded best to steroids. This seronegative autoimmune autonomic neuropathy is a distinct clinical entity requiring a different treatment approach from AAG.