Guillain-Barré syndrome is an autoimmune disease that mainly affects muscle movements and can manifest itself through many variants.

In this article we will discuss the symptoms, causes and treatment of Miller Fisher syndrome , one of the most common forms of this disorder.

What is Miller Fisher syndrome?

Miller Fisher syndrome is a disease that affects the nervous system, causing symptoms associated with muscle movement and coordination . In some cases it can also cause alterations in other physiological systems.

This is one of the possible manifestations of Guillain-Barré syndrome, a group of diseases that occur as a result of infections that in turn cause an inadequate functioning of the immune system.

Miller Fisher syndrome generally has a good prognosis: if appropriate medical treatment is applied the symptoms tend to go into complete remission . However, this is not always the case, and if the damage to the nervous system is significant, some sequelae may remain.

Approximately twice as many cases of Miller Fisher syndrome are detected in women than in men, and the prevalence is higher in the spring than at other times of the year. The average age of onset of the disease is slightly above 40 years.

Guillain-Barré syndrome

Guillain-Barré syndrome is an autoimmune disorder ; this means that it consists of a malfunctioning of the immune system that leads it to “attack” healthy cells in the body. In this case the injuries take place in the peripheral nervous system, affecting the muscles of the extremities first, and sometimes leading to complete paralysis.

In the most severe cases this disease causes death due to the alteration in the functioning of the cardiac and respiratory systems. It is usually caused by viral infections, although the exact mechanisms by which it occurs are not known.

The differential diagnosis between Miller Fisher syndrome and other variants of Guillain-Barré syndrome is made on the basis of the presence of characteristic signs and symptoms. Let’s see what the peculiarities of the subtype in question are.

Main symptoms and signs

There are three essential signs that characterize Miller Fisher syndrome compared to other forms of Guillain-Barré syndrome: ataxia, areflexia and ophthalmoplegia . These changes usually appear 5 to 10 days after a viral infection is contracted.

Ophthalmoplegia and ataxia are usually the first signs of the disease. The former consists of paralysis of the eyeball muscles, while ataxia is defined as a loss of motor coordination . On the other hand, areflexia, which occurs in third place and mainly in the extremities, is the absence of reflex movements.

The other idiosyncratic feature of this variant of Guillain-Barré syndrome is the involvement of the cranial nerves, which is associated with deficits in nerve conduction.

In some cases, other alterations associated with the same lesions are produced, fundamentally generalised muscular weakness and respiratory deficits , which may lead to death if the symptoms are very intense. However, these problems are more common in other forms of Guillain-Barré syndrome.

Causes of this disease

Although Miller Fisher syndrome is often attributed to infections by viruses (and to a lesser extent by bacteria), it has not been proven that these are the only possible cause of this disease.

The signs and symptoms are due to the destruction of the myelin sheaths of the peripheral nerves by the immune system. Myelin is a lipid substance that coats the axons of some neurons, allowing the efficient transmission of nerve impulses and increasing their speed.

However, alterations have also been detected in the central nervous system, in particular in the back of the spinal cord and in the brain stem.

On the other hand, the antiganglioside immunoglobulin antibody GBQ1b has been found in most people diagnosed with Miller Fisher syndrome. This antibody appears to be particularly associated with the presence of ophthalmoplegia.

Treatment and handling

Like other Guillain-Barré syndrome variants, Miller Fisher disease is treated by two procedures: plasmapheresis, which consists of removing antibodies from the blood by filtration, and the administration of immunoglobulins intravenously.

Both techniques are very effective in neutralizing the effects of pathological antibodies and in reducing inflammation, which also causes damage to the nervous system, but combining them does not significantly increase the probability of success of the intervention. However, the administration of immunoglobulins carries less risk .

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Most people begin to recover after two weeks to a month of treatment, provided it is applied early. After six months, there are usually no or very few symptoms and signs, although there is sometimes a risk of sequelae and a 3% risk that they will reappear after they disappear.