Morvan's Syndrome

1. Morvan Syndrome
Ade Wijaya, MD – October 2021

2. Outline:
 Introduction
 Pathophysiology
 Clinical presentation
 Diagnosis
 Management
 Differential diagnosis
 Prognosis
 Summary

3. Introduction
 First discribed by French physician on 1890, Dr.
Augustine Marie Morvan
Peripheral nerve
hyperexcitability
Encephalopathy
Autonomic
instability
associated with autoantibodies to voltage-gated potassium channel complexes
(VGKCs)
Masood W, KK S. Morvan syndrome. StatPearls. Treasure Island: StatPearls
Publishing. 2021.

4. Pathophysiology
 Antibodies against VGKC complex proteins,
CASPR2, and LGI1 are now strongly implicated in
the pathogenesis of Morvan syndrome
 Male preponderance; CASPR2 protein-coding
mRNA in the prostate gland
Lee EK, Maselli RA, Ellis WG, Agius MA. Morvan's fibrillary chorea: a paraneoplastic manifestation of thymoma. J Neurol Neurosurg Psychiatry. 1998 Dec;65(6):857-
62.
Irani SR, Pettingill P, Kleopa KA, Schiza N, Waters P, Mazia C, Zuliani L, Watanabe O, Lang B, Buckley C, Vincent A. Morvan syndrome: clinical and serological obser
29 cases. Ann Neurol. 2012 Aug;72(2):241-55.

5. Clinical Presentation
 Central nervous system
 Autonomic nervous system
 Peripheral nervous system
Masood W, KK S. Morvan syndrome. StatPearls. Treasure Island: StatPearls
Publishing. 2021.

6. Central Nervous System
 Encephalopathy
 Severe insomnia
 Vivid complex hallucinations
 Delirium
 Spatial and temporal disorientation
 Confusion
 Amnesia
 Agitation
 Belligerence
Lotan I, Djaldetti R, Hellman MA, Benninger F. Atypical case of Morvan's syndrome. J Clin Neurosci. 2016
Mar;25:132-4.

7. Autonomic Nervous System
 Excessive sweating
 Fever
 Palmoplantar erythema
 Pruritus
 Drooling
 Severe constipation
 Excessive lacrimation
 Arrhythmias
 Hypertension
 Weight loss
 Syndrome of inappropriate antidiuretic hormone secretion
Josephs KA, Silber MH, Fealey RD, Nippoldt TB, Auger RG, Vernino S. Neurophysiologic studies in Morvan syndrome. J Clin Neurophysiol. 2004 Nov-Dec;21(6):440-5.
Buckley C, Oger J, Clover L, Tüzün E, Carpenter K, Jackson M, Vincent A. Potassium channel antibodies in two patients with reversible limbic encephalitis. Ann
Neurol. 2001 Jul;50(1):73-8.

8. Peripheral Nervous System
 Neuropathic pain
 Areflexia (loss of deep tendon reflexes)
 Stocking-type sensory loss
 Continuous muscle fiber activity is manifested as
neuromyotonia which is clinically seen as myokymia
Iwasaki Y, Kinoshita M, Ikeda K, Takamiya K, Shiojima T. Concurrence of myasthenia gravis and chorée fibrillaire de Morvan. Eur Arch Psychiatry Neurol Sci. 1990;239(

9. Diagnosis
 Clinical diagnosis
 EMG studies can confirm myokymia
 Detection of VGKC-complex antibodies
 Association with Thymoma
Masood W, KK S. Morvan syndrome. StatPearls. Treasure Island: StatPearls
Publishing. 2021.

10. Management
 Antiepileptic agents such as carbamazepine,
valproate, phenobarbital, phenytoin
 Thymectomy in thymoma associated cases
 Plasma exchange
 Immunotherapy
Josephs KA, Silber MH, Fealey RD, Nippoldt TB, Auger RG, Vernino S. Neurophysiologic studies in Morvan syndrome. J Clin Neurophysiol. 2004 Nov-
Dec;21(6):440-5

11. Differential Diagnosis
 Limbic encephalitis
 Acquired Neuromyotonia or Isaac Syndrome: a
disorder similar to Morvan syndrome with peripheral
nerve hyperexcitability but without overt CNS or ANS
dysfunction
 Guillain-Barre Syndrome
 Familial fatal insomnia (FFI) – prion disease
Masood W, KK S. Morvan syndrome. StatPearls. Treasure Island: StatPearls
Publishing. 2021.

12. Prognosis
 Variable
 Some cases have been reported to remit
spontaneously
 Some required extensive treatment, mainly in the
form of immunotherapy including plasma exchange
and long-term immunosuppression.
 Some cases were fatal.
 The overall prognosis of Morvan syndrome was
particularly poor when associated with thymoma
Masood W, KK S. Morvan syndrome. StatPearls. Treasure Island: StatPearls
Publishing. 2021.

13. Summary
 Autoimmune disease
 Peripheral nerve hyperexcitability, autonomic
instability, and encephalopathy
 Clinical diagnosis
 Plasma exchange
 Variable prognosis: poor prognosis in thymoma-
related

14. THANK YOU