Miller Fisher Syndrome

What is Miller Fisher Syndrome?

Miller Fisher syndrome (MFS) is a rare neurological disease. It is an acquired disease that is a variant of Guillain-Barré syndrome (GBS). Miller Fisher syndrome is also known as Fisher’s syndrome. This syndrome is often preceded by a viral infection just like GBS. Symptoms usually start very quickly over days. The symptoms usually resolve spontaneously or resolve after a few weeks of treatment. The three signs of this syndrome are weak eye muscles with double vision/blurred vision, poor balance/coordination and loss of deep muscle reflexes. MFS is named after Dr. C Miller Fisher who first described the syndrome in 1956.

People affected with MFS usually only show one of the three signs of the disease. Some people have other nerves affected by MFS like the cranial nerves and some have paresis of muscles in their necks, shoulders and arms. Sometimes MFS leads to GBS. Approximately 1/3 of people affected by MFS have cases that lead to GBS with worsening weakness or respiratory failure. About five percent of people affected by GBS began as MFS.

MFS does not run in families. The incidence of MFS is not known but is estimated to be between 1 to 2 million a year affected by MFS. There are no clear geographical areas for MFS. Men are more often affected by MFS than women are. MFS is seen in people of all ages including children. Is Miller Fisher syndrome contagious? No. [1, 2, 3, 4]

miller fisher syndrome



The causes of MFS are not fully understood. There is some loss of fat in the myelin sheath surrounding the nerves. This loss of fat causes coordination problems. There is evidence to support an auto immune response is to play with MFS as well. It looks like the preceding infection causes antibody production that reacts to a sugar that is found on the nerves causing the demyelination. [2]

Signs and Symptoms

  • Previous gastro-intestinal illness or respiratory illness in the weeks preceding
  • Loss of voluntary muscle coordination and movements
  • Difficulty walking (clumsy)
  • Absence of deep muscle reflexes
  • Paralysis of the eye muscles (in and around the eye)
  • Weak eye muscles
  • Slurred speech
  • Difficulty swallowing
  • Drooping eye lids with facial weakness/abnormal facial expression
  • Inability to smile or whistle
  • Poor coordination of the hands
  • Enlarged or dilated pupils
  • Decreased gag reflex
  • Diminished nerve activity on nerve conduction study
  • Without prominent signs of peripheral neuropathy
  • Double vision
  • Blurred vision [1, 2, 3]



When the person affected with new symptoms goes to see a physician, the MD will complete a physical examination. The examination will show different symptoms outlined above. Nerve conduction testing may be ordered to show more information about how the nerves are acting and if there is any diminished activity in the nerves. MRI or other imaging of the brain may be ordered. MRI studies will help rule out other causes like brain stem disorders or meningitis. These scans are usually normal in MFS.

There will often be an evaluation of the spinal fluid protein and it is often elevated. Cerebro-spinal fluid analysis will also help rule out other causes like meningitis or lymphomatosa. The patient will need to be evaluated by an ophthalmologist to rule out other causes and for a complete diagnosis. Blood work will be ordered looking at serum antibodies to the ganglioside GQ1b. Other laboratory testing will help rule out infections, metabolic causes and toxic causes of the symptoms.

nerve conduction study Miller Fisher Syndrome

Differential Diagnosis

  • Subacute ataxia without eye muscle paralysis
  • Subacute eye muscle paralysis without ataxia
  • Guillain-Barré syndrome without eye muscle paralysis
  • Guillain-Barré syndrome (lower bulbular)
  • Bickerstaff encephalitis
  • Brain stem lesions
  • Neuro-muscular transmission disorders
  • Meningitis lymphomatosa
  • Metabolic disorders
  • Infections
  • Intoxications
  • Deficiencies [2]


Supportive treatment is usually effective given the benign course of the syndrome. People are usually hospitalized to make sure the syndrome will not progress into GBS. Usually with pure MFS, recovery is usually seen in two to three months. People that begin to have swallowing problems will need to have specific treatment. Sometimes IV immunoglobulin or plasma exchange may help extreme cases. [1, 2]

plasma exchange Miller Fisher Syndrome

Miller Fisher Syndrome Prognosis

Most people affected with MFS have complete remission without residual effects. Most people get better quickly. Some people affected with MFS will get bulbular weakness with swallowing difficulties. This sometimes turns into GBS and can lead to severe breathing problems or severe muscle weakness. As mentioned before 1/3 of people affected by MFS have cases that lead to GBS. [1]

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Reference List:

  1. Disabled World, Available from:
  2. GPS/CIDP Foundation International, Available from:
  3. ISNO, Available from:
  4. NCBI, Available from:
  5. Pinterest, Available from:
  6. My Healthy Feeling, Available from:
  7. Palo Brea Pain and Rehabilitation, Available from:
  8. Asahi Kasei Medical, Available from:

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