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Miller Fisher Syndrome

Miller Fisher Syndrome

The Miller Fisher Syndrome is an extremely rare autoimmune disorder of the nervous system, and is usually triggered by infections. It is characterized by peripheral neuropathy that manifests in the form of descending paralysis.
Gaynor Borade
The Miller Fisher syndrome is named after the pioneering neurologist, Charles Miller Fisher, who first described it in 1956.
The Miller Fisher syndrome is a special case or variant of the Guillain-Barré syndrome (GBS), an autoimmune disorder that affects the peripheral nervous system. GBS is a rare disorder, in which the immune system of an individual acts against the nervous tissue, leading to muscle weakness, loss of autonomic function and even paralysis. Miller Fisher syndrome accounts for about 5% of the GBS cases.
GBS is characterized by ascending paralysis, i.e., the feet, legs and hands are affected first, and the weakness and tingling migrate to the trunk and other body parts. The exact reverse of this, is a condition called descending paralysis, which is observed in case of Miller Fisher syndrome. Here, the eye muscles get affected first followed by the other body parts.
Given below are the causes, symptoms, diagnostic parameters, and treatment options available for Miller Fisher syndrome.
Causes
Although the etiology behind this disorder is not yet clear, it has been associated with certain viral and bacterial infections. Certain microbes use molecular mimicry to escape the immune system of the body. Such a mechanism, involving the mimicry of gangliosides present in the nerve tissue has been postulated to trigger an autoimmune response.
Gangliosides are complex glycosphingolipids located on the surface of cells present in the nervouse tissue. Certain infectious agents like Campylobacter jejuni, express on their membrane, lipopolysaccharide molecules that mimic the structure of gangliosides. The immune system identifies foreign agents through the antigens and molecules present on their surface. As a result, the immune system detects the lipopolysaccharides, and antibodies are generated against them. Owing to the structural similarity, these antibodies act against the normal ganglioside-bearing cells of the nervous tissues as well. Such autoimmune reaction is then manifested in the form of inflammation of myelin and paralysis.
Signs and Symptoms
As mentioned earlier, descending paralysis is a characteristic manifestation of Miller Fisher syndrome. The symptoms are often experienced 1-4 weeks after a viral or bacterial infection. Affected individuals show a rapid development of:
» Ophthalmoplegia: Paralysis and weakening of eye muscles leading to drooping of eyelids, blurred vision, as well as facial weakness.
» Ataxia: Abnormal muscle coordination leading to poor balance and altered gait.
» Areflexia: Loss of tendon reflexes like the knee-jerk reflex and elbow reflexes.
Other symptoms that may be experienced are
♦ Slurred speech
♦ Bladder dysfunction
♦ Decreased gag reflex
♦ Difficulty in swallowing
♦ Reduced ability to sense pain and temperature

Individuals with typical Miller Fisher syndrome generally do not exhibit weakness of limb muscles. However, the condition may unpredictably proceed to limb paralysis, and other manifestations of the Guillain-Barré syndrome. Breathing difficulty usually signals the onset of Guillain-Barré syndrome. Respiratory failure may be experienced in severe cases.
Diagnosis
» Physical examination coupled with assessment of reflexes and coordination is an important part of diagnosis for the Miller Fisher syndrome.

» Cerebrospinal fluid (CSF) is collected and tested. Abnormally high protein content with a normal white blood cell count may be observed in case of individuals with Miller Fisher syndrome. However, this is not a definite criteria for diagnosis, since certain individuals with Miller fisher syndrome may not have any abnormality in CSF.

» Nerve conduction study (NCS) is performed to evaluate the observed symptoms, and confirm the diminished activity of nerves.

» Imaging techniques like magnetic resonance imaging (MRI) of the brain and spinal cord may be advised to confirm the absence of any other neural conditions.

» Blood test may be advised to check for the presence of anti-GQ1b antibody (a type of anti-ganglioside antibody). This antibody is present in about 90% of the cases.
Treatment
Plasmapheresis and/or administration of intravenous immunoglobulin (IVIg) are the main treatment options, and they aim to reduce the immune reaction and prevent further damage.

» Plasmapheresis is a technique where blood is collected; the plasma is isolated and treated; and the blood cells and plasma are injected back into the patient. In individuals with Miller Fisher syndrome, plasmapheresis is performed for the removal of anti-GQ1b antibodies.

» The IVIg administered is a neutralizing antibody against the anti-GQ1b antibody. Generally, a combination of both the methods is suggested for faster recovery.

Symptomatic treatment and supportive care plays a very important role in the treatment plan adopted for the syndrome. Most Miller Fisher patients may display signs of recovery within the first 2-4 weeks of treatment, and may completely recover in six months. Relapses occur rarely, and have been observed only in 3% of the cases. Neglecting the initial symptoms may lead to fatal complications, necessitating immediate professional consultation.
Disclaimer: This article is for informative purposes only, and should not be used as a substitute for professional medical advice.