Cervical dystonia is characterized by involuntary tonic contractions or intermittent spasms of neck muscles. The cause is usually unknown. Diagnosis is based on history and physical examination. Treatment may include physical therapy, medications, 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. Cervical dystonia is the most common dystonia.
There are 2 forms of cervical dystonia:
Caput: When the most proximal cervical vertebrae (C1 or C2) are involved
Collis: When any of the lower cervical vertebrae (C3 to C7) are involved
The caput form (torticaput) involves muscles that move the head at the atlanto-occipital and atlanto-axial joints; it is further described as anterocaput, laterocaput, or retrocaput. The collis form involves muscles that control the lower cervical vertebrae and is further described as anterocollis, laterocollis, retrocollis, or torticollis. Differentiating the 2 forms is important because it helps clinicians identify the correct muscles to inject with botulinum toxin.
Spasmodic adult-onset torticollis is the most common form of cervical dystonia. It is usually idiopathic. A few patients have a family history, and a genetic cause has been identified in some (eg, those with dystonia-6 [DYT6; associated with THAP-1], dystonia-4 [DYT4; associated with TUBB4A], or dystonia-25 [DYT25; associated with the GNAL gene]). Some of these patients have other dystonias (eg, of the eyelids, face, jaw, or hand).
Cervical dystonia can be
Congenital (idiopathic or hereditary)
Secondary (related to conditions such as lesions of the central nervous system [brain stem or basal ganglia] or use of dopamine-blocking medications [eg, haloperidol])-blocking medications [eg, haloperidol])
Rarely, dystonia has a psychogenic cause. The pathophysiology of psychogenic dystonia is not well-understood although 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. Treatment may require a multidisciplinary team, including a neurologist, psychiatrist, and psychologist.
Symptoms and Signs of Cervical Dystonia
Cervical dystonia symptoms may begin at any age but usually begin between ages 20 and 60 years, with a peak between ages 30 and 50 (1).
Symptoms usually begin gradually; rarely, they begin acutely and progress rapidly. Symptoms may begin with a tremor that rotates the neck (in a no-no gesture).
The cardinal symptom of cervical dystonia is
Painful tonic contractions or intermittent spasms of the sternocleidomastoid, trapezius, and other neck muscles, usually unilateral, that result in an abnormal head position
Unilateral sternocleidomastoid muscle contraction causes the head to rotate to the opposite side. Rotation may involve any plane but usually has a horizontal component. Besides rotational tilting (torticollis), the head can tilt laterally (laterocollis), forward (anterocollis), or backward (retrocollis, common when dopamine-blocking medications are the cause). Similarly, in the caput form, the head may tilt laterally (laterocaput), forward (anterocaput), or backward (retrocaput).
Patients may discover sensory or tactile tricks that lessen the dystonic posturing or tremor (geste antagoniste). Touching the face on the side contralateral to the deviation is an example. Such tricks typically do not lessen psychogenic tremor, and thus noting whether a sensory trick is effective can help clinicians differentiate pathophysiologic dystonia from psychogenic dystonia.
The presence of overflow or mirroring also indicates that a pathophysiologic etiology (eg, genetic, idiopathic, brain injury) is likely. Overflow refers to involuntary dystonic movement in another part of the body, distant to the primary voluntary movement. In mirroring, when patients voluntarily move the affected side of their body, they involuntarily mimic that movement with the opposite side of the body.
During sleep, muscle spasms disappear.
Spasmodic torticollis ranges from mild to severe. Usually, it progresses slowly for 1 to 5 years, then plateaus. Approximately 10 to 15% of patients recover or significantly improve spontaneously within 5 years of onset (usually in milder cases with onset at a younger age). However, in many of those who improve, symptoms recur (2).
Symptoms and signs references
1. Norris SA, Jinnah HA, Espay AJ, et al. Clinical and demographic characteristics related to onset site and spread of cervical dystonia. Mov Disord. 2016;31(12):1874–1882. doi: 10.1002/mds.26817
2. Jahanshahi M , Marion MH , Marsden CD. Natural history of adult-onset idiopathic torticollis. Arch Neurol. 1990;47(5):548–552. doi: 10.1001/archneur.1990.00530050070014
Diagnosis of Cervical Dystonia
History and physical examination
The diagnosis of cervical dystonia is based on characteristic symptoms and signs and exclusion of alternative diagnoses, including the following:
Tardive dystonia 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 central nervous system (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 medications can cause acute torticollis, but the symptoms usually develop in hours and resolve within days after the medication is stopped.
Congenital muscular torticollis (fibromatosis colli) is caused by a benign tumor in the sternocleidomastoid muscle. The tumor causes foreshortening of the muscle and tilting of the neck, mimicking cervical dystonia. Head tilting usually appears during infancy or childhood but can occur during adulthood (1).
The collis form of dystonia (involving muscles that control the cervical spine) can usually be distinguished from the caput form (involving muscles that move the skull or head joints that move the head) based on observation of the patient. Imaging (CT bone window), in addition to history and physical examination, is useful only for assessing rotation of the head. Lateral shift always occurs when laterocollis is present on one side and laterocaput on the other (2).
Diagnosis references
1. Gonzalez-Usigli H, Espay AJ. A rare cervical dystonia mimic in adults: Congenital muscular torticollis (fibromatosis colli). Front Neurol. 2013;4(6). doi: 10.3389/fneur.2013.00006
2. Reichel G. Cervical dystonia: A new phenomenological classification for botulinum toxin therapy. Basal Ganglia. 2011;1(1): 5-12. doi: 10.1016/j.baga.2011.01.001
Treatment of Cervical Dystonia
Physical measures
Sometimes botulinum toxin or oral medications
Spasms can sometimes be temporarily inhibited by physical therapy and massage, including sensory biofeedback techniques (eg, slight tactile pressure to the jaw on the same or other side as head rotation) and any light touch.
Medications
Injections of botulinum toxin type A or B into the dystonic muscles can reduce painful spasms for 1 to 4 months in approximately 70% of patients, restoring a more neutral position of the head (1, 2). However, in a few cases, when the toxin is repeatedly injected, it becomes less effective because neutralizing antibodies against the toxin develop.
Oral medications can usually relieve pain, but they suppress dystonic movements in only approximately 25 to 33% of patients. These medications include
Anticholinergic medications, such as trihexyphenidyl, but adverse effects possibly limit their useAnticholinergic medications, such as trihexyphenidyl, but adverse effects possibly limit their use
Benzodiazepines (particularly clonazepam)Benzodiazepines (particularly clonazepam)
Baclofen Baclofen
Carbamazepine Carbamazepine
All medications should be started in low doses, especially in older adults. Doses should be increased until symptoms are controlled or intolerable adverse effects (particularly likely in older adults) develop.
Surgery
One procedure selectively severs nerves to affected neck muscles, permanently weakening or paralyzing them.
If hereditary generalized dystonia, medication-refractory dystonia, or primary focal dystonia is severe, deep brain stimulation (DBS) is a reasonable option for successfully controlling dystonic features (3). This procedure targets the area of the basal ganglia regulating the dystonia, especially the globus pallidus internus.
Treatment references
1. Spiegel LL, Ostrem JL, Bledsoe IO. FDA Approvals and Consensus Guidelines for Botulinum Toxins in the Treatment of Dystonia. Toxins (Basel). 2020;12(5):332. doi:10.3390/toxins12050332
2. Albanese A, Asmus F, Bhatia K, et al. EFNS guidelines on diagnosis and treatment of primary dystonias. Eur J Neurol. 2011;18(1):5-18. doi: 10.1111/j.1468-1331.2010.03042.x
3. Volkmann J, Mueller J, Deuschl G, et al. Pallidal neurostimulation in patients with medication-refractory cervical dystonia: a randomised, sham-controlled trial. Lancet Neurol.2014;3(9):875-884. doi: 10.1016/S1474-4422(14)70143-7
Key Points
Spasmodic torticollis is a common adult-onset cervical dystonia and is usually idiopathic.
Diagnosis is clinical and involves exclusion of tardive dystonia, basal ganglia disorders, CNS infections, neck infections and tumors, and medications.
Usually, treat with physical measures, botulinum toxin injection, and/or oral medications.
