DYSTONIA
Philip A. Hanna, M.D.
Parkinson's Disease and Movement Disorders Center
New Jersey Neuroscience Institute
Edison, New Jersey
Dystonia is a neurologic condition characterized by involuntary
sustained or intermittent, patterned, repetitive muscle contractions,
frequently resulting in twisting, flexing or extending (e.g. writer's
cramp, retrocollis), pulling, squeezing movements or abnormal
postures. Typically, dystonia begins in a single body part (focal
dystonia), such as the hand, neck or eyelids, and then may spread to
adjacent body areas (segmental dystonia). Blepharospasm is a focal
dystonia with involuntary eye closure secondary to contractions of the
eyelids and eyebrows. Oromandibular dystonia, when associated with
clenching (trismus) and grinding of teeth (bruxism), may result in
dental and temporal-mandibular joint (TMJ) difficulties. Cervical
dystonia affects neck muscles and is commonly called "torticollis"
(rotation of head). However, individuals may also have flexion,
extension or tilting of the head. Spasmodic dysphonia is a focal
dystonia of the larynx, resulting in a strained voice pattern which
may be interrupted by voiceless pauses uncontrollable pitch breaks or
voiceless pauses (adductor form) or a breathy, soft voice (abductor
form). Cervical dystonia is the most common form of dystonia seen in
specialized clinics, though "writer's cramp" (a
task-specific dystonia) is likely more common in the general
population. Dystonia may spread to involve the legs, trunk and other
body parts (generalized dystonia), particularly if the onset is during
childhood. Hemidystonia refers to dystonia which is confined to only
one half of the body. This form of dystonia often has an identifiable
cause such as head trauma, stroke, tumor, or other pathology.
There have been recent discoveries including the identification of a
gene for idiopathic Jewish and non-Jewish autosomal dominantly
transmitted dystonia in the q34 region of chromosome 9. Not all
dystonias are of genetic origin as some are sporadic and others are
due to specific causes, including Wilson's disease, neurodegenerative
disorders, toxins and both dopaminergic and anti-dopaminergic drugs.
The treatment of this conditions has dramatically improved, largely
due to the use of botulinum toxin (BTX). About a third of patients
benefit from medications. A small group of patients with childhood
onset dystonia improve markedly with levodopa. Surgical techniques,
such as local denervation, thalamatomy and pallidotomy, are only used
if other treatment modalities have not provided satisfactory benefit.
Dystonia Medical Research Foundation
One East Wacker Drive, Suite 2430
Chicago, IL. 60601-1905
(312) 755-0198
Hanna PA, Cardoso F, Jankovic J. Basal Ganglia and Movement Disorders.
In: Rolak LA, ed. Neurology Secrets, 2nd ed. New York: Hanley and
Belfus, 1998:137-169.
Jankovic J, Fahn S. Dystonic syndromes. In Jankovic J, Tolosa E., eds.
Parkinson's disease and movement disorders, 3rd edition. Baltimore,
William & Wilkins, 1998:513-551.
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