Reduplicative paramnesia in Morvan's syndrome.

BACKGROUND

Morvan's syndrome is characterized by peripheral nervous system hyperexcitibility (myokymia and neuromyotonia), hyperhydrosis, sleep disorder, limb paresthesias, and encephalopathy. Voltage gated potassium channel antibodies (VGKC abs) are frequently present. Reduplicative paramnesia (RP) has not been reported with this disorder.

OBJECTIVE

To describe a patient with Morvan's syndrome presenting with RP.

DESIGN

Single case study.

PATIENT: A 64-year-old man with several years of myokymia and myoclonus with escalating parasomnia and confusion developed the delusion that a replica of his house and its contents existed 40 mi away.

RESULTS

Serum VGKC ab titer was elevated. Neuropsychological testing disclosed executive function and memory deficits. Electromyography demonstrated diffuse myokymia. Treatment with intravenous immunoglobulin and prednisone produced improvement of RP and myoclonus, but not myokymia.

CONCLUSION

RP may occur in patients with VGKC ab-associated Morvan's syndrome. Both RP and nervous system hyperexcitability may respond to immunotherapy including intravenous immunoglobulin and corticosteroids.