Miller-Fisher Syndrome – Symptoms, Diagnosis And Treatment
Miller-Fisher syndrome is a variant of Guillain-Barre syndrome, characterized by ophthalmoplegia, ataxia and areflexia. These clinical signs can overlap with other signs and symptoms of Guillain-Barre syndrome.
Although it is assumed that Miller-Fisher syndrome is idiopathic, it was observed that this disease can develop after a recent viral, bacterial or mycoplasma infections and after vaccinations. Association with Campylobacter jejuni infection was also mentioned . In Japan have also been reported cases of Miller-Fisher syndrome in the same family, suggesting a genetic predisposition for this disease. Miller-Fosher syndrome occurs in both sexes, with a slight predominance in males.
Miller-Fisher Syndrome Symptoms
Clinically, symptomatic triad consisting of ophthalmoplegia, ataxia and areflexia is characteristic for this syndrome.
Ophthalmoplegia tends to be complete, sometimes have been observed cases of internuclear ophthalmoplegia and Parinaud syndrome (a group of abnormalities of eye movement and pupil dysfunction). Palpebral ptosis is also present and may be unilateral or bilateral, symmetrical or asymmetrical, complete or incomplete. Pupillary disturbances occur in over 50% of cases of Miller-Fisher syndrome and are characterized by reduction of pupillary reaction to light, accommodation disorders and anisocoria (unequal size of the pupils).
Ataxia is a result of peripheral non-myelinated spinocerebellar fibers conduction disturbances , being a truncal ataxia.
Have been reported cases of Miller-Fisher syndrome associated with retrobulbar optic neuritis and accompanied by vision loss, with complete or incomplete vision recovery.
Cranial nerve impairment occurs, especially of the facial nerve, causing facial paralysis which can be unilateral or bilateral. Other cranial nerves which can be affected are ophthalmic branch of cranial nerve V (trigeminal nerve) and cranial nerve VIII (acoustic). Cranial nerves II (optic) and III (oculomotor) are less affected in this disease.
A characteristic of Miller-Fisher syndrome is the occurrence of migratory paresthesias, which are not usually accompanied by sensitive deficits. Sometimes, cases of sensitive ataxia have been reported.
Neurological disorders in Miller-Fisher syndrome affects, in most cases, the peripheral nervous system. In some patients were reported impairments of central nervous system, accompanied by dysarthria, nystagmus, ataxic gait, ophthalmoparesis, pronounced tendon reflexes and positive Babinski sign). In some cases distinction between Miller-Fisher syndrome and brainstem encephalitis is very difficult.
Miller-Fisher Syndrome Diagnosis
Miller Fisher syndrome is diagnosed based on symptomatic triad consisting of ophthalmoplegia, ataxia and areflexia and parclinical examinations.
Serological tests reveal the presence of antibodies directed against certain gangliosides. It seems that anti-GQ1b antibody, of IgG type correlates with ophthalmoplegia in Guillain-Barre syndrome and may correlate with ophthalmoplegia appeared in Miller-Fisher syndrome. In one case of Miller-Fisher syndrome were detected anti-cerebellar antibodies. Miller-Fisher syndrome patients present changes in cebrospinal fluid identical to those of Guillain-Barre syndrome (increased protein concentration over 400 mg / dl, but a normal cellularity, anomaly called albuminocytological dissociation).
Electrophysiological tests are abnormal in most cases and advocates for peripheral nerve dysfunction (electromyography, nerve conduction, F waves, visual evoked potentials, sensory evoked potentials and auditory brain stem evoked potentials). Nerve biopsy reveal demyelination associated with axonal degeneration.
Neuroimagistically, ophthalmoparesis was confirmed by peripheral lesions of oculomotor nerve.
Miller-Fisher Syndrome Treatment
In most patients with Miller-Fisher syndrome spontaneous remission occurs after a period of 8-12 weeks of evolution, without treatment. Relapses are possible, but are not characteristic for the disease. Some cases with severe evolution, require mechanical ventilation. In severe forms of disease plasmapheresis is useful. Intravenous administration of immunoglobulin, in doses of 400 mg / kg / day for a period of 5 days was shown to be effective.
Currently, the problem of concomitant impairment of central nervous system, supported by some authors, remains an open controversy for the following research. Are taken into account two alternatives: either the Miller-Fisher syndrome is a single entity caused by inflammatory and demyelinating lesions, located both in the peripheral nervous system and central nervous system; either the syndrome is caused by different pathological processes, some of which only affect the central nervous system, others affect only peripheral nervous system and others affect both the central nervous system and peripheral nervous system.