Cervical Dystonia

Cervical dystonia (CD), also known as spasmodic torticollis, belongs to a group of disorders known as focal dystonias. Patients with CD have involuntary contractions of the neck and shoulder muscles that cause the head to twist in abnormal positions.1 Neck muscles may also contract repetitively, producing uncontrollable head movements.

Head and neck movements may occur in any direction. The chin may twist toward the shoulder, or the head may tilt forward, backward, or to the side.

CD occurs in 9 out of every 100,000 individuals.4 Approximately 5% to 16% of patients with CD have a history of head or neck trauma preceding the onset of dystonia.3 The cause of CD, however, is not yet known.

The most obvious clinical sign in patients with CD is an abnormal head position. The movement abnormalities and pain associated with CD can be disabling. Although onset may occur at any age, CD typically occurs in adults between the ages of 30 and 70. Women are nearly twice as likely to be affected with CD as men.4

Some patients develop sensory tricks (geste antagoniste) to help them cope with the pain associated with CD. By touching their faces, chins, or heads, individuals can temporarily reduce or compensate for the dystonic symptoms. Many patients even develop sensory tricks to help them improve posture during social situations.

BOTOX® (Botulinum Toxin Type A) Purified Neurotoxin Complex blocks the nerve impulses that trigger muscle activity. The neurotoxin is thought to chemically inhibit the release of the neurotransmitter acetylcholine from nerve endings by binding to certain receptors on cholinergic terminals. It is then engulfed by the nerve endings. Once inside a nerve ending, the neurotoxin interferes with the cholinergic vesicles that release acetylcholine. This interference leads to chemodenervation and reduced muscular contractions.

The National Institutes of Health (NIH), American Academy of Neurology (AAN), and American Academy of Ophthalmology (AAO) have recognized BOTOX® as a safe and effective treatment for the symptomatic relief of CD.

The duration of effect for each BOTOX® treatment is approximately three months. Patients eventually return to pretreatment status at which point they can be reinjected over time with the neurotoxin as long as they continue to respond and do not have a serious allergic reactions.5

Patients or caregivers should be advised to seek immediate medical attention if swallowing, speech, or respiratory disorders occur.5

Patients with CD should be informed of the possibility of having difficulty swallowing (also known as dysphagia), which is typically mild to moderate, but could be severe. Rare consequences of severe dysphagia include aspiration, shortness of breath, pneumonia, and the need to reestablish an airway.5

Patients with neuromuscular disorders may be at increased risk of clinically significant systemic effects including severe dysphagia and respiratory compromise from typical doses of BOTOX®. The effects of therapy may be increased with the use of aminoglycoside antibiotics or with other drugs that interfere with neuromuscular transmission. There have been rare spontaneous reports of death, sometimes associated with dysphagia, pneumonia, and/or other significant debility, after treatment with botulinum toxin.

The most frequently reported side effects associated with BOTOX® include dysphagia (19%), upper respiratory infection (12%), neck pain (11%), and headache (11%).6 Other events reported in 2% to 10% of patients, in decreasing order of incidence, include increased cough, flu syndrome, back pain, rhinitis, dizziness, hypertonia, soreness at the injection site, asthenia, oral dryness, speech disorder, fever, nausea, and drowsiness.5

In general, adverse events occur within the first week following injection of BOTOX® and while generally transient may have a duration of several months. Localized pain, tenderness and/or bruising may be associated with the injection. Local weakness of the injected muscle(s) represents the expected pharmacological action of botulinum toxin. However, weakness of adjacent muscles may also occur due to spread of toxin.

1. Fahn S, Marsden CD, Calne DB. Classification and investigation of dystonia. Mov Disord. 1987;2:332-358.
2. Data on File, Allergan, Inc.
3. Van Zandijcke M. Cervical dystonia (spasmodic torticollis). Some aspects of the natural history. Acta Neurol Belg. 1995;95(4):210-215.
3. Chan J, Brin MF, Fahn S. Idiopathic cervical dystonia: clinical characteristics. Mov Disord. 1991;6:119-126.
4. BOTOX® Full Prescribing Information.
5. Data on file, Allergan, Inc. 1999