Morvan's syndrome

90% of cases spontaneously go into remission, while the other 10% of cases lead to death

Multiple irregular contractions of the long muscles cramping, weakness.
Pruritus: Profuse perspiration with characteristic skin miliaria (Sweat rash)
Insomnia: Severe insomnia, amounting to no less than complete lack of sleep (agrypnia)
Delirium: Remarkable hallucinatory behavior
Myokymia (Muscle twitching + Muscle pain)
Neuromyotonic discharges: peculiar motor disturbances
Autonomic dysfunction (Sympathetic over activation)
- Hyperhidrosis
- Tachycardia
- Increased body temperature
- Hypertension

The subject presented with muscle weakness and fatigue, muscle twitching, excessive sweating and salivation, small joint pain, itching and weight loss.
Confusional episodes with spatial and temporal disorientation,
Visual and auditory hallucinations,
Complex behavior during sleep and progressive nocturnal insomnia associated with diurnal drowsiness. (RBD parasomnia)
Severe constipation
Urinary incontinence
Excessive lacrymation
When left alone, the subject would slowly lapse into a stuporous state with dreamlike episodes characterized by complex and quasi-purposeful gestures and movements (enacted dreams).
Marked hyperhidrosis and excessive salivation
Neurological examination disclosed diffuse muscle twitching and spontaneous and reflex myoclonus, slight muscle atrophy in the limbs, absence of tendon reflexes in the lower limbs
Diffuse erythema esp on the trunk with scratching lesions of the skin.
Compulsive behaviours, stereotypies and reduplicative paramnesias can be part of the CNS spectrum.

There is no need for sleep was severely reduced and in some cases not necessary.
Sleep duration in one case decreased to about 2–4 hours per 24-hour period.
Daytime drowsiness associated with a loss of ability to sleep, intermingled with confusional oneiric status, and the emergence of
Atypical REM sleep from wakefulness.
Polysomnogram (PSG) picture:
- Suppression of stage 2 non-REM sleep
- REM sleep without atonia.
The involvement of the thalamus and connected limbic structures in the pathology indicate the prominent role that the limbic thalamus plays in the pathophysiology of sleep.

Neuromyotonia refers to muscle twitching and cramping at rest that is exacerbated with exercise.

Laryngospasm: Breathing difficulties can occur, resulting from neuromyotonic activity of the laryngeal muscles.

Anti-acetylcholine receptors antibodies have also been detected in patients with thymoma, but without clinical manifestations of myasthenia gravis.
There have also been reports of non-paraneoplastic limbic encephalitis associated with raised serum VGKC suggesting that these antibodies may give rise to a spectrum of neurological disease presenting with symptoms arising peripherally, centrally, or both. Yet, in two cases, oligoclonal bands were absent in the CSF and serum, and CSF immunoglobulin profiles were unremarkable.

Antibodies against voltage-gated potassium channels (VGKC), which are detectable in about 40% of patients with acquired neuromytonia, have been implicated in Morvan's pathophysiology.
Raised serum levels of antibodies to VGKCs have been reported in three patients with Morvan's Syndrome.
Binding of serum from a patient with Morvan's Syndrome to the hippocampus in a similar pattern of antibodies to known VGKC suggest that these antibodies can also cause CNS dysfunction.
Anti-VGKC antibodies cause nerve hyperexcitability associated with acquired neuromyotonia and Morvan's Syndrome.
VGKC antibodies may cross the blood–brain barrier and act centrally, binding predominantly to thalamic and striatal neurons causing encephalopathic and autonomic features.

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