What is Miller Fisher Syndrome?

miller fisher syndrome
Miller Fisher Syndrome (MFS) is a rare nerve disease. It is a derivative of Guillain-Barre Syndrome and is named after the famous neurologist, Dr. C. Miller Fisher. The main symptoms that define MFS are loss of muscle control, paralysis in the eyes (also known as ophthalmoplegia), and the reduction or absence of tendon reactions

The symptoms gradually carry out of a period of about a week. First, a patient with MFS will start to experience double vision or eye weakness. Then the muscles in the face will lose tension, causing the face to droop downwards. Additional complications caused by MFS include respiratory problems and overall muscle fatigue. 

As mentioned above, MFS is extremely rare. According to Healthline, it only affects about 1-5% of those with Guillain-Barre Syndrome (GBS). But what causes this rare nerve disease?

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Causes of Miller Fisher Syndrome

A complex network of nerves directly connects to and communicates with our brains, telling us when to move, breathe, blink, and feel pain. Our brain is like a computer that can transmit signals to our nerves in a fraction of a millisecond, commanding them to complete particular functions.

MFS is an auto-immune disease, which means the body’s immune system attacks its nerve endings. The immune system damages the myelin sheath, which is the protective coating around the nerves. When this coating is damaged, so are the signals from the brain. The affected nerves are the ones that connect to the face and eyes. 

How Common Is Miller Fisher Syndrome?

Miller Fisher Syndrome is extremely rare, especially in the Western world. As mentioned above, it is a variation of GBS, which only affects 1 in 100,000 people. Roughly 1-5% of those with GBS have MFS. Since the disease is rare, it’s difficult for medical professionals to conduct thorough research and develop sufficient treatments. The low number of patients with MFS also makes it challenging for practitioners to diagnose MFS. 
blurred vision

Symptoms of Miller Fisher Syndrome

The main symptom of MFS is muscle weakness in the face and eyes. The nerves connecting the eye muscles are damaged first, and then the disease slowly works its way down to other parts of the face. Here are the most common symptoms of Miller Fisher Syndrome:

  • Double Vision (blurred vision is also common)
  • Loss of strength in the facial muscles – Patients with MFS have trouble smiling, talking, and eating 
  • Loss of balance
  • Slower reaction time in the knees and legs
  • Difficulty walking

Patients with both GBS and MFS often exhibit these symptoms. To specify whether or not a patient has MFS, they will need to see a physician who can further diagnose their condition. 

How Is Miller Fisher Syndrome Diagnosed?

There are various ways a doctor can diagnose MFS. Most of the time, they conduct a physical exam to test the patient’s muscular strength and reaction time. They will also ask important questions such as what symptoms they are experiencing and how long the symptoms have been present. 

The doctor may ask a series of questions about the patient’s medical history. If needed, they will conduct thorough scans of the brain to see any abnormal activity. Oftentimes, a patient may be experiencing a brain injury or stroke instead of MFS, which requires a different type of treatment. 

Another effective method for diagnosing Miller Fisher Syndrome is a blood test. Here, the doctor analyzes the blood sample for anti-GQ1b antibodies, which are commonly present in those with GBS and MFS. These antibodies are responsible for attacking the coating around the nerves. Doctors can also manipulate the spine to test nerve velocity, which is also effective for diagnosis. 

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Treatment Options for Miller Fisher Syndrome

Since MFS is a variation of GBS, the treatment options are interchangeable. There are two main treatment options deemed most effective by the National Institute of Neurological Disorders and Stroke (NINDS):

  1. Immunoglobulin proteins are injected into the bloodstream. This is by far the more favorable option since it’s quicker and easier to carry out.
  2. A plasma exchange takes place to clean the blood. This is more difficult and time-consuming than the first option.

There are additional treatment options for specific patients. Some may need to use a heart monitor to keep their vitals in check, while others may need a ventilator to help them breathe. These treatments may require the patient to stay at the hospital to be monitored closely by a doctor.

There is no direct cure for Miller Fisher Syndrome. The treatment options are designed to aid the patient during recovery, although the injection or plasma exchange could help speed up recovery and alleviate some disease symptoms. Treatment can also prevent the disease from progressing or getting worse. 

If a patient’s MFS develops into GDS, they are at a much higher risk of having more severe life-threatening symptoms. This happens to about 30% of patients and is rare if a doctor is consistently monitoring them. 

Who Is at Risk of Miller Fisher Syndrome?

Technically speaking, anyone can contract Miller Fisher Syndrome. However, some demographics may be more vulnerable than others. Those include:

  • Men – Studies have shown that men are twice as likely to develop Miller Fisher Syndrome than women.
  • People Aged 40 to 50 – The average age of those who develop MFS is 43 years.
  • Men From Japan – 25% of the cases of GBS in men from Japan were MFS. That’s 20% higher than the Western world. 

FAQs About MFS

miller fisher syndrome faq

Is MFS curable?

Luckily the prognosis for Miller Fisher Syndrome is bright. Most patients start to see recovery as early as 2-4 weeks after treatment. In most cases, recovery will be complete within six months. Some patients might relapse, but it’s quite rare.

Is Miller Fisher Syndrome an auto-immune disease?

Yes, MFS is an auto-immune disease. The immune system sends out antibodies to attack the coating around nerves connected to the eye and face muscles. This attack weakens or eliminates signals from the brain, causing muscle weakness. 

Is Miller Fisher Syndrome hereditary?

Though there have been some links to familial GBS, there hasn’t been any evidence of MFS being a hereditary disease. MFS is caused by a viral infection which leads to the underlying symptoms. 

How do I know if I have MFS?

Diagnosing MFS needs to be done by a medical professional. If you are experiencing any of the symptoms of MFS, you must seek medical attention right away. 

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Miller Fisher Syndrome is a rare condition, and doctors are still learning about the disease. There are still questions about why a small percentage of patients with GBS develop MFS while others don’t, but more research is being done to determine the root cause and alternative treatment options.

The best way patients can assist their doctor is to provide a thorough report of previous medical conditions, family history, and symptoms. This information will allow doctors to better understand the disease and why it develops in the first place. 


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