• Clinical science

Rare neurological diseases


Rare neurological diseases may be inherited, postinfectious, iatrogenic, or of unknown etiology. They can affect the brain, spinal cord, or peripheral nerves. Symptoms range from mild tremors to significant motor and cognitive impairment. Therapy is often supportive.

SMON (subacute myelo-optic neuropathy)

  • Etiology: iatrogenic (induced by the drug clioquinol)
  • Epidemiology: Most cases were confined to Japan in the 1960's. Oral clioquinol was removed from the market in the 1980's.
  • Clinical features
    • Progressive paralysis
    • Blindness
  • Treatment: reversible (withdraw clioquinol)

Elsberg syndrome

  • Etiology: HSV-2 infection is most common but other viral etiologies (i.e., CMV, EBV, HIV) are possible → sacral myeloradiculitis
  • Clinical features: transient urinary retention
  • Treatment: supportive (i.e., urethral catheterization)

Kleine-Levin syndrome

  • Epidemiology: mainly affects adolescent males
  • Etiology: unknown (although viral infections have been implicated)
  • Clinical features
    • Recurrent hypersomnia (patients are only awake for 1–2 h per day)
    • Hyper-sexuality when awake
    • Binge eating
  • Treatment: supportive

Prion diseases

Diseases caused by prion infection. Prion diseases affect both animals and humans. Creutzfeldt-Jakob disease (CJD) and variant CJD are discussed in a separate card.


  • Etiology: rapidly lethal prion infection; acquired through ritualistic cannibalism → neuronal loss, gliosis, and spongiform degeneration of the brain gray matter
  • Clinical features
    • Cerebellar ataxia
    • Muscle tremors
    • Pathological laughter
  • Treatment: supportive

Gerstmann-Sträussler-Scheinker syndrome

  • Etiology: rapidly lethal prion infection → deposition of amyloid plaques, mainly in the cerebellum
  • Clinical features
    • Cerebellar ataxia
    • Dysarthria
    • Nystagmus
    • Late-onset dementia
  • Treatment: supportive




Central core disease

  • Etiology: congenital myopathy
  • Epidemiology: appears during childhood
  • Clinical features
    • Proximal muscle weakness
    • Kyphoscoliosis
    • Hip dysplasia
    • Developmental delay
  • Treatment: symptomatic and supportive

Lance-Adams syndrome

  • Etiology: hypoxic brain damage
  • Clinical features: myoclonus of different forms (possibly in combination with asterixis and cerebellar ataxia)
  • Treatment: antimyoclonic agents

Giant axonal neuropathy

  • Etiology: autosomal recessive chronic degenerative neurological disease
  • Clinical features
  • Treatment: supportive

Tolosa-Hunt syndrome

  • Etiology: unknown
  • Pathophysiology: granulomatous inflammation in the area of the cavernous sinus or the superior orbital fissure
  • Clinical features
    • Severe retro-ocular pain
    • Eye muscle paresis (ophthalmoplegia)
  • Treatment: prednisone


Cramp fasciculation syndrome

  • Etiology: general peripheral nerve hyperexcitability disorder of unknown etiology
  • Clinical features
  • Treatment: supportive

Periodic limb movement disorder

  • Etiology: unknown
  • Pathophysiology: idiopathic malfunction of the dopaminergic system
  • Clinical features: periodic arm and leg movements
  • Treatment: benzodiazepines, dopaminergic agents, or antiepileptics drugs (e.g, gabapentin)

Empty sella syndrome

  • Etiology: idiopathic
  • Pathophysiology: enlargement or malformation of the sella turcica → compression of the pituitary gland
  • Clinical features
    • Often asymptomatic
    • Some patients may experience chronic headache.
  • Treatment: symptomatic


Denny-Brown syndrome

Vertical gaze palsy


HTLV-1 associated myelopathy


Neurodegeneration with brain iron accumulation 1

Oculogyric crisis

last updated 01/18/2019
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