Peduncular Hallucinosis and Overlapping Antiganglioside Antibody Syndrome

Abstract

Guillain Barre Syndrome (GBS), Miller Fisher Syndrome (MFS) and Bickerstaff Brainstem Encephalitis (BBE) form part of the same disease spectrum, sharing some clinical signs and auto-immune based mechanisms with antiganglioside antibodies. GBS, the most common cause of subacute flaccid paralysis, is a well-known and extensively described syndrome. MFS is characterized by subacute ophthalmoplegia, ataxia and areflexia. In 1957, Bickerstaff described some patients who, in addition to ataxia and ophthalmoplegia, had abnormal mental status, corresponding to brainstem involvment. Neurological manifestations associated with anti-GQ1b antibodies can occur in isolation or in association. We report the case of a woman with an unusual psychiatric presentation (peduncular hallucinosis) of anti-GQ1b antibody syndrome, with features of these three diseases, and a dramatic improvement with immunoglobulin therapy. Peduncular hallucinosis are a rare form of visual hallucination. They are often described as colourful visions of people and animals, and are usually associated with vascular lesions in the midbrain and thalamus. This provides further evidence of the broad spectrum of neurological diseases associated with antiganglioside antibodies. To the best of our knowledge this is the first description of PH complicating BBE. Clinicians should be aware of the existence of overlapping syndrome with combined central and peripherical neurological system involvement.