Cervical dystonia is characterized by involuntary tonic contractions or intermittent spasms of neck muscles. The cause is usually unknown. Diagnosis is clinical. Treatment can include physical therapy, drugs, and selective denervation of neck muscles with surgery or locally injected botulinum toxin.
(See also Overview of Movement and Cerebellar Disorders.)
In cervical dystonia, contraction of the neck muscles causes the neck to turn from its usual position. It is the most common dystonia.
Spasmodic (adult-onset) torticollis is the most common form of cervical dystonia. It is usually idiopathic. A few patients have a family history, and in some of them (eg, those with dystonia-6 [DYT6], dystonia-7 [DYT7], or dystonia-25 [DYT25; associated with the GNAL gene]), a genetic cause has been identified. Some of these patients have other dystonias (eg, of the eyelids, face, jaw, or hand).
Cervical dystonia can be
Rarely, dystonia has a psychogenic cause. In this type of dystonia, pathophysiology is not well understood; however, changes in brain function have been detected by functional neuroimaging. In many cases, an emotional stressor or an abnormal core of beliefs is identified as a trigger. In such cases, a multidisciplinary team, including a neurologist, psychiatrist, and psychologist, is necessary.
Cervical dystonia symptoms may begin at any age but usually begin between ages 20 and 60, with a peak between ages 30 and 50.
Symptoms usually begin gradually; rarely, they begin acutely and progress rapidly. Sometimes symptoms begin with a tremor that rotates the neck (in a no-no gesture).
The cardinal symptom is
Unilateral sternocleidomastoid muscle contraction causes the head to rotate to the opposite side. Rotation may involve any plane but almost always has a horizontal component. Besides rotational tilting (torticollis), the head can tilt laterally (laterocollis), forward (anterocollis), or backward (retrocollis, common when dopamine-blocking drugs are the cause).
Patients may discover sensory or tactile tricks that lessen the dystonic posturing or tremor (eg, touching the face on the side contralateral to the deviation). During sleep, muscle spasms disappear.
Spasmodic torticollis ranges from mild to severe. Usually, it progresses slowly for 1 to 5 yr, then plateaus. About 10 to 20% of patients recover spontaneously within 5 yr of onset (usually in milder cases with onset at a younger age). However, it may persist for life and can result in restricted movement and postural deformity.
The diagnosis of cervical dystonia is based on characteristic symptoms and signs and exclusion of alternative diagnoses, including the following:
Tardive dyskinesia can cause torticollis but can usually be distinguished by a history of chronic antipsychotic use and involuntary movements in muscles outside of the neck.
Basal ganglia disorders and occasionally CNS infections can cause movement disorders but usually also involve other muscles; CNS infections are usually acute and cause other symptoms.
Neck infections or tumors are usually differentiated by features of the primary process.
Antipsychotics and other drugs can cause acute torticollis, but the symptoms usually develop in hours and resolve within days after the drug is stopped.
Injections of botulinum toxin type A or B into the dystonic muscles can reduce painful spasms for 1 to 4 mo in about 70% of patients, restoring a more neutral position of the head. However, in a few cases, when the toxin is repeatedly injected, it becomes less effective because neutralizing antibodies against the toxin develop.
Oral drugs can usually relieve pain, but they suppress dystonic movements in only about 25 to 33% of patients. These drugs include
All drugs should be started in low doses (eg, trihexyphenidyl 2 mg po tid). Doses should be increased until symptoms are controlled or intolerable adverse effects (particularly likely in the elderly) develop.
Spasmodic torticollis is a common adult-onset cervical dystonia and is usually idiopathic.
Diagnosis is clinical and involves exclusion of tardive dyskinesia, basal ganglia disorders, CNS infections, neck infections and tumors, and drugs.
Treatment is most often physical measures, botulinum toxin injection, and/or oral drugs.