CASPR-2 related morvan’s syndrome: Autonomic, polysomnographic & neuropsychological observations

Background & Objectives:Morvan’s syndrome is characterized by central, autonomic, and peripheral hyperexcitability due to CASPR-2-antibody. Our objective was to study the clinical spectrum, electrophysiological, autonomic, polysomnographic and neuropsychological profile in patients of CASPR-2 related Morvan’s syndrome. Materials & Methods: Serum and CSF samples that were CASPR2-antibody positive from 2016-2019 were assessed. Among them, patients of Morvan’s syndrome diagnosed based on clinical and electrophysiological basis were included. Results: 14(M: F-10:4) patients of Morvan’s syndrome were included with age at onset of 37.1±17.5 years. The clinical features were muscle twitching (12), insomnia (12), pain (11), paraesthesias (9), hyperhidrosis (7), hypersalivation (6), double incontinence (3), spastic speech (2), dysphagia (2), behavioral disturbances (2), seizures (1) cold intolerance (1). Neurological examination revealed myokymia (12), hyperactive tendon reflexes (10), tremor (6). Electromyogram revealed neuromyotonia (12) and increased spontaneous activity (7). Autonomic function tests conducted in eight patients revealed definite autonomic dysfunction (4), orthostatic hypotension (2), early dysfunction (1) and postural orthostatic tachycardia syndrome (1). Polysomnography findings done in six patients revealed insomnia (3), absence of deep sleep (1), high frequency beta activity (1), REM (rapid eye movement) behaviour disorder(1), periodic leg movements(1). Neuropsychological evaluation showed subtle involvement of the left frontal and temporal lobe. Malignancy workup was negative. All patients were treated with steroids. There was complete neurological resolution in follow-up with persistent neuropathic pain in five patients. Conclusions: This study has contributed to the growing knowledge on CASPR2-related Morvan’s syndrome. It is important for an increased awareness and early recognition as it’s potentially treatable by immunotherapy.