Dystonic phenomena in MS patients hospitalized during 1992-2002
in the 1st Department of Neurology of Aristotelian University of Thessaloniki

Multiple sclerosis (MS) is the most representative demyelinating disease characterized by myelin destruction with relative sparing of axons, which leads to disturbance of function. At times, toxic, metabolic, mechanic, inflammatory, hereditary/genetic and environmental factors, as well as, immune deficiency have been suggested as causes for the pathogenesis of the disease. The incidence of the disease varies around different regions of the world. The highest prevalence is noted in northern countries, whereas the lowest in countries near the Equator. The prevalence of MS patients in Greece is 35/100.000.

Dystonias comprise a spectrum of heterogenic diseases characterized by involuntary motional disorders, which result in derangement of the posture and disturbance of the harmonic body movements, either in part or in whole, caused by protracted and, sometimes, painful contraction of the synergistic and antagonistic muscles. A retrospective study has been conducted, concerning dystonic phenomena manifested by patients with clinically definite multiple sclerosis (MS) according to Poser's criteria. The clinical signs and symptoms, the laboratory examinations, the course of the disease and the medication have been recorded and studied from 200 files of patients with definite MS, who were hospitalized in the 1st Department of Neurology of Aristotelian University of Thessaloniki from 1992 to 2002.

Two out of 200 patients with MS, specifically one male and one female, manifested dystonic phenomena during the course of the disease.

The first patient was a 67-year-old man suffering from primary progressive type of MS. The diagnosis was confirmed at the age of 39. He manifested a dystonic posturing of the right hand, with palmar flexion and outward inversion, and pseudoathetosic movements. T1-weighted sequences of brain MRI, demonstrated decreased signal intensity foci in periventricular white matter areas. During his hospitalization multivitamin preparations and tizanidine hydrochloride were administered, having presented negligible signs of improvement.

The second patient was a 41-year-old woman with the relapsing/remitting type of MS. The diagnosis was confirmed at the age of 24. During the forth relapse of her disease, she manifested facial hemispasm. Brain MRI studies indicated the presence of T2-weighted bright foci periventricularly, especially in the occipital lobes, in the centri cemiovali, the basal gaglia and subtentorialy. Her condition was improved with oral administration of amantadine hydrochloride.

Dystonia is caused by lesions that affect the extrapyramidal system, which consists of the striatum, the red nucleus, the substantial nigra, the globus pallidus, the subthalamic nucleus and multiple neuronic circuits connecting the cortex, the basal gaglia, the cerebellum, the reticular formation and the spinal cord.

It is common knowledge that MS is characterized by multiple demyelinating areas into the white matter, termed plaques.

Several studies, co-relating dystonic phenomena in MS patients with the location of the lesions in CNS, demonstrate the presence of lesions mainly in periventricular white matter and, specifically, in the multiple neuronic circuits connecting the basal gaglia with the other nuclei of the extrapyramidal system.

The results of the study show that 1% of patients with MS manifested dystonic phenomena and, in particular, facial hemispasm and dystonic posture of hand.

Although dystonic phenomena in MS have been proved to be rare, they do occur. According to the literature, writer's cramp, blepharospasm, partial dystonias and torticollis have been noted to be of common occurrence. However, the studies performed so far are rare and often insufficient and, therefore, further epidemiological studies should be conducted.

Key words: Dystonic phenomena, multiple sclerosis.