IMMUNOTHERAPY-REVERSED COMPULSIVE, MONOAMINERGIC, CIRCADIAN RHYTHM DISORDER IN MORVAN SYNDROME

Abstract

Antibodies to voltage-gated potassium channels (VGKC-Abs) have been recognized in neuromyotonia, limbic encephalitis (LE), and Morvan syndrome (MoS),1,2 a rare condition with insomnia, peripheral, and central and autonomic nervous system involvement. Clinical progression in MoS is variable, but potentially fatal. We describe a patient with VGKC-Abs-positive MoS who showed prominent compulsive behaviors, basal ganglia hypermetabolism, increased catecholamine and serotonin secretion, epileptic seizures, and cardiac and endocrine circadian rhythm suppression. A striking response to immunotherapy paralleled a marked reduction in VGKC-Abs over 15 months. ### Case report. A 64-year-old man with idiopathic pulmonary fibrosis and polyarthrosis developed cramps, lower extremity pain, and sensory loss. Three years later, his sleep was disturbed by chewing, manual stereotypies, and sleep-talking. After an episode of tonic-clonic seizures, EEG revealed a temporal epileptic focus. He developed paroxysmal confusional episodes, with gesturing and irregular breathing, that were unresponsive to multiple anticonvulsants. He became irritable and hypomanic with overwhelming compulsive shopping and stealing. Urinary frequency, anosmia, impotence, and increased appetite appeared. Examination showed bilateral postural tremor, multifocal myoclonus, lower extremity fasciculations, hypoesthesia, hyporeflexia, and mild proximal muscle atrophy. Laboratory investigations, including autoimmune and thyroid profile, were normal except for increased leukocytes, a raised erythrocyte sedimentation rate and creatine phosphokinase, mild hyponatremia, and antinuclear antibodies 1:160. CSF was negative for infections and 14.3.3 protein, but showed slightly increased …