Torsion Dystonia has been defined as a syndrome characterized by sustained involuntary movements causing torsion, twisting and repetitive movements resulting in bizarre or abnormal postures of the limb and trunk. Depending on the part of body affected, Dystonia may be focal (affecting single body part) segmental (two or more body parts) multifocal or generalized.
Torsion dystonia is a rare disease which is familial and large number of cases are autosomal dominant inherited. Genetic linkage studies have shown a positive correlation to markers on chromosome 9.
Most cases begin in early childhood or early adolescence. The first abnormality is noticed when patient walks. There is spasmodic plantar flexion of the feet and patient does toe walking. This soon involves the rest of the body. Movements in upper limbs consist of rotation or torsion round the long axis.
Vertebral column also shows similar movements and there is lordosis and scoliosis. Muscular tone is exaggerated especially during the spasms but there is no muscular wasting and reflexes as well as sensations are normal.
Progression of the Torsion Dystonia disease is rapid in cases which have onset in early childhood. Besides muscles of limbs, lingual, pharyngeal, neck, and thoracic muscles also may show spasms.
Most of the cases of torsion dystonia are familial with a hereditary linkage. Sporadic cases may also occur. Picture like torsion dystonia may occur in Wilson’s disease, kernicterus, encephalitis, degenerative disorders (X-linked dystonia, Parkinson’s disease, Hutington’s disease) and diseases with known metabolic defect (HallervordenSpatz disease, basal ganglia calcification).
There are no studies to demonstrate any substantive neuro pathological changes in this condition. But degenerative changes have been seen in the caudate nucleus and putamen in few cases.
Focal and segmental dystonias
These usually develop in later life and appear sporadically. Spasmodic torticollis is the most common in this group and involves dystonic movements of the neck.
It affects women more as compared to men. There is involuntary turning of head to one side which is intermittent to start with but soon may become continuous. Tarticollis means rotation of head to one side.
Cranial dystonia also referred to as Meige’s syndrome involves cranial muscles. There is blepharospasm with tonic closure of eyelids. As it involves the throat and respiratory muscles there is interference with speech production.
Treatment of Torsion Dystonia is unsatisfactory. Dystonic spasms may be relieved by benzodiazipenes (chlordiazepoxide 30-100 mg. Diazepam 10-30 mg, lorazepam 1-4 mg, alaprozalam (0.75-1.5 mg), which may be given in high doses. Anticholinergic agents (trihexyphenidyl 20-50 mg daily and ethopropazine) have also proved beneficial. In fact combination of anticholinergics and benzodiazipines may work well. For focal dystonia especially involving the face, local injections of botulinum toxin (BOTOX) into the orbicularis oculi muscles is helpful.