A Case of Morvan Syndrome Mimicking Amyotrophic Lateral Sclerosis with Frontotemporal Dementia

Brin Freund, Manoj Maddali, Thomas E. Lloyd

Research output: Contribution to journalArticlepeer-review

Abstract

Introduction: Morvan syndrome is a rare autoimmune/paraneoplastic disorder involving antibodies to the voltage-gated potassium channel complex. It is defined by subacute encephalopathy, neuromuscular hyperexcitability, dysautonomia, and sleep disturbance. It may present a diagnostic dilemma when trying to differentiate from amyotrophic lateral sclerosis with frontotemporal dementia. Methods: A 76-year-old man with a history of untreated prostate adenocarcinoma was evaluated for subacute cognitive decline, diffuse muscle cramps, and hyponatremia. Results: MRI demonstrated atrophy most prominent in the frontal and temporal regions. Electromyography (EMG) demonstrated diffuse myokymia/neuromyotonia. Polysomnography lacked REM and N3 sleep. Paraneoplastic panel detected antibodies to voltage-gated potassium channel complex (CASPR2 subtype). Conclusions: It is difficult to differentiate between Morvan syndrome and amyotrophic lateral sclerosis with frontotemporal dementia with examination and neuroimaging alone. There may be a link between Morvan syndrome and prostate adenocarcinoma which could help with screening/diagnosis. The authors found that laboratory and neurophysiological tests are indispensable in diagnosing and treating Morvan syndrome.

Original languageEnglish (US)
Pages (from-to)207-211
Number of pages5
JournalJournal of Clinical Neuromuscular Disease
Volume17
Issue number4
DOIs
StatePublished - Jun 1 2016

Keywords

  • Morvan syndrome
  • amyotrophic lateral sclerosis
  • frontotemporal dementia
  • myokymia
  • neuromyotonia
  • voltage-gated potassium channel

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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