Version May 2024
INTRODUCTION — Cervical dystonia, also known as spasmodic torticollis or simply torticollis, is one of the most common adult-onset focal dystonias. It is a hyperkinetic movement disorder that manifests with varying degrees of abnormal neck posturing, neck tremor, and/or neck pain. Although generally benign, cervical dystonia can lead to significant disability if untreated, and it is often underrecognized and misdiagnosed.
Literary and artistic references to individuals with abnormal neck postures date back centuries, but recognition of the neurologic rather than psychologic etiology of the condition was not established until the 20th century [1-3]. The diagnosis is made primarily through awareness of the disorder and attention to detail during the neurologic examination. Ancillary testing is seldom necessary to establish an accurate diagnosis.
This topic will review the known causes of cervical dystonia, key features of the neurologic examination that facilitate the diagnosis, and management. Other forms of dystonia in adults are reviewed in more detail separately. (See "Etiology, clinical features, and diagnostic evaluation of dystonia" and "Treatment of dystonia in children and adults".)
Congenital and acquired forms of torticollis in children, which are considered distinct entities from cervical dystonia, are also reviewed separately. (See "Congenital muscular torticollis: Clinical features and diagnosis" and "Congenital muscular torticollis: Management and prognosis" and "Acquired torticollis in children".)
EPIDEMIOLOGY
●Incidence and prevalence – Cervical dystonia is one of the most frequent focal dystonias and the most common adult-onset dystonia in some parts of the world. The estimated prevalence ranges from 5 to 30 cases per 100,000 individuals [4,5]. The incidence in the United States has been estimated at 1.18 per 100,000 person-years [6].
●Risk factors – Cervical dystonia is approximately two times more common in females than males [6-8]. Reasons for the sex predominance are not known. Other risk factors are not well understood.
Soft tissue trauma as a risk factor for idiopathic cervical dystonia is controversial. In a case-control study of 67 patients with cervical dystonia and 67 of their age-matched unaffected siblings, a history of surgery (odds ratio [OR] 4.9) and a car accident requiring hospitalization (OR 7.3) were each associated with increased risk of dystonia on multivariable analysis [9]. Other retrospective studies have also identified recent neck trauma as a potential risk factor, although functional movement disorders can also arise in this setting and can be difficult to exclude as a contributing factor [10,11]. (See "Functional movement disorders", section on 'Functional dystonia'.)
ETIOLOGY
Idiopathic — Most cases of adult-onset cervical dystonia are idiopathic. Although the cause is unknown, genetic susceptibility is presumed to play an important role. It has been theorized that most adult-onset dystonias are inherited as an autosomal-dominant trait with very reduced penetrance. Environmental factors, such as neck trauma, may promote disease among genetically predisposed individuals. (See 'Epidemiology' above.)
Genetic — Rare cases of focal-onset dystonia in adults are monogenetic. Genetic variants known to cause adult-onset isolated cervical dystonia include:
●CIZ1 – An exonic splicing enhancer variant in exon 7 of the CDKN1A interacting zinc finger protein 1 (CIZ1) gene has been found to cause cervical dystonia in a large kindred with European ancestry and in the absence of ataxia, spasticity, oculomotor abnormalities, parkinsonism, or neuropathy [12]. CIZ1 encodes a zinc finger protein expressed in the brain and involved in DNA synthesis and cell cycle control.
●ANO3 – Pathogenic variants in anoctamin 3 (ANO3) are a rare cause of sporadic and familial cervical dystonia as well as familial craniocervical dystonia [13]. ANO3 encodes a predicted calcium-gated chloride channel that is highly expressed in the basal ganglia.
●GNAL – Pathogenic variants in the G protein subunit alpha L (GNAL) gene were first identified in patients with isolated cervical dystonia, although some individuals also exhibit limb and segmental dystonia [14]. GNAL encodes the stimulatory alpha subunit, G(olf)alpha, first identified as a G-protein mediating odorant signaling in the olfactory epithelium. In medium spiny neurons, G(olf)alpha couples dopamine type 1 receptors of the direct pathway and adenosine A2A receptors of the indirect pathway to activate adenylyl cyclase type 5.
A larger number of dystonia syndromes, many of which are genetic, can manifest with cervical dystonia in combination with other neurologic abnormalities. (See 'Associated dystonia syndromes' below.)
Acquired — Cervical dystonia arising from exposure to dopamine receptor blocking agents is the primary example of an acquired etiology in adults. It comes in two forms, acute and delayed (tardive). Medication-induced dystonia is important to recognize because management and natural history differ from idiopathic cases.
●Acute dystonic reaction – Cervical dystonia can occur as part of an acute dystonic reaction to certain medications, primarily first-generation antipsychotic agents, metoclopramide, and prochlorperazine. Other medications reported to cause acute dystonic reactions include antidepressants (particularly selective serotonin reuptake inhibitors), antivertigo agents, antiseizure medications, antimalarial agents, and cocaine [15]. The reaction typically occurs within 24 hours of medication administration and is usually characterized by torticollis or retrocollis as well as oculogyric crisis (fixed gaze deviation) and opisthotonos (jaw clenching). It is often painful and frightening to the patient. Treatment consists of diphenhydramine or benztropine. (See "Schizophrenia in adults: Maintenance therapy and side effect management", section on 'Dystonia'.)
●Tardive cervical dystonia – Tardive dyskinesia includes a subset of patients with prominent dystonia, rather than or in addition to the more common choreiform dyskinetic movements. Tardive cervical dystonia often appears as prominent jerky retrocollis. It may occur in relative isolation or, more commonly, in combination with dystonia in other regions (typically in the trunk), retrocollis, and oro-bucco-lingual and facial dyskinesia [16].
When tardive cervical dystonia is isolated, it can be indistinguishable from idiopathic cervical dystonia, and the only way to make the diagnosis is to document an exposure to dopamine receptor blocking agents prior to the onset of the dystonic symptoms. (See "Tardive dyskinesia: Etiology, risk factors, clinical features, and diagnosis".)
PATHOGENESIS — Cervical dystonia has classically been considered a disease of the basal ganglia. Like other dystonias, however, it is increasingly recognized as a network disease, of which the basal ganglia are a component.
●Central network dysfunction – A central network that governs head posturing, termed the "head neural integrator," was first described in nonhuman primates and likely exists in humans [17]. The proposed head neural integrator acts similarly to oculomotor neural integrators that allow for stability of primary gaze. In this model, cervical dystonia (particularly with prominent neck tremor) is conceptualized as a form of "head nystagmus," similar to gaze-evoked nystagmus that occurs with dysfunction of the ocular integrator (in which a slow-phase horizontal eye drifting is followed by a fast corrective saccade in the opposite direction). It has been hypothesized that deep brain stimulation (DBS) for cervical dystonia may work by correction of the afferents to the head integrator [18].
Components of the head neural integrator network likely include the basal ganglia (putamen and external globus pallidum), frontoparietal cortex (sensorimotor areas), brainstem (interstitial nucleus of Cajal), cerebellum, and cervical muscle spindles [18-23]. Elegant studies using a variety of functional neuroimaging and electrophysiologic techniques suggest that abnormalities anywhere within the network can lead to dystonia.
●Pathologic correlates – No clear pathologic correlates have been identified in the few neuropathologic studies that have been performed in patients with cervical dystonia [24,25]. Quantitative magnetic resonance imaging (MRI) techniques, which can identify subtle parenchymal brain changes and track them as they progress over time, have shown numerous and at times conflicting findings [26,27]. Other studies suggest that structural changes in the cerebellum play a role in pathogenesis, at least in some patients [28,29].
●Genetic insights – On a molecular level, insights from some of the genetic forms of generalized dystonia may prove to be relevant to idiopathic cervical dystonia [30,31]. As an example, dysfunction in the eukaryotic initiation factor 2-alpha (eIF2α) signaling pathway is implicated in DYT1, DYT6, and DYT16 dystonia as well as in sporadic cervical dystonia. Under physiologic circumstances, phosphorylation of eIF2α leads to downstream upregulation of activating transcription factor 4 (ATF4), which, in turn, favors the expression of stress response proteins. In one study, ATF4 upregulation was abnormally diminished in DYT1 fibroblasts subjected to endoplasmic reticulum stress [30]. In the same study, rare, likely gene-disrupting (missense) variations in the ATF4 gene were identified in 8 out of 239 patients (3.3 percent) with sporadic cervical dystonia, compared with 0.5 percent of controls.
Monogenetic causes of cervical dystonia are reviewed above. (See 'Genetic' above.)
CLINICAL FEATURES
Clinical presentation — Cervical dystonia typically presents in mid-adulthood. Approximately 70 to 80 percent of cases occur between the fourth and sixth decades of life [7,8,32]. Disease onset before the fourth decade of life is rare and should raise suspicion for genetic or acquired dystonia [8,32,33]. (See "Etiology, clinical features, and diagnostic evaluation of dystonia", section on 'Clinical features'.)
The onset of symptoms is often gradual and insidious. Diagnostic delay of up to several years is common, especially when symptoms are mild, intermittent, or slowly progressive [6,34]. In patients presenting with the complaint of neck pain or stiffness, clinicians may fail to recognize mild posturing or prioritize pain management over diagnostic inquiry. Neck pain is often initially ascribed to cervical disc disease or neck sprain/strain. Essential tremor (ET) is a common misdiagnosis in patients with an associated head tremor. In other patients, complaints are misattributed to anxiety, depression, or functional symptoms [6]. (See 'Differential diagnosis' below.)
Neck posturing — Abnormal neck posture is the defining feature of cervical dystonia and is present in all patients. Dystonic posturing is present during wakefulness and generally subsides during sleep, in the absence of chronic musculoskeletal deformities that may arise due to sustained neck posturing over months or years.
Postures are named based on the plane and direction in which the movement occurs (figure 1). The postures exist in pure forms and in combination (except for antero- and retrocollis, which are mutually exclusive) [7]:
●Torticollis – Rotation to either direction in the transverse plane
●Laterocollis – Lateroflexion to either direction in the coronal plane
●Retrocollis – Retroextension in the sagittal plane
●Anterocollis – Anteroflexion in the sagittal plane
●Sagittal shift – Base of the neck is shifted in the sagittal plane
●Horizontal (lateral) shift – Base of the neck is shifted towards either shoulder
Posture classification can be further refined based on primary head (caput) movements into 10 abnormal neck postures using the collis-caput (Col-Cap) concept (figure 1) [35-37]. In a study of 306 patients with cervical dystonia, the most common primary Col-Cap forms were torticaput (49 percent) and laterocaput (17 percent) [37]. The remaining eight subtypes each composed less than 10 percent of the cohort. Most patients exhibited a combination of two or more postures, most commonly torticaput plus laterocaput. Careful characterization of the dystonic movements may increase the accuracy of candidate muscle selection for botulinum toxin (BoNT) therapy. (See "Cervical dystonia: Treatment and prognosis", section on 'Botulinum toxin injections'.)
Tremor — Approximately 70 percent of patients with cervical dystonia also have tremor, most often involving the head [7,38]. Hand tremor of any form (not necessarily dystonic) can also occur. Neck tremor may be more common among females, patients with hand tremor, and those with a family history of movement disorders [38].
The pattern of the head/neck tremor in patients with cervical dystonia can be either jerky (with a slow drift phase followed by a fast corrective phase) or sinusoidal (symmetric oscillations around an axis). A sinusoidal pattern is classically described in patients with ET and is sometimes discussed as a differentiating feature between dystonic neck tremor and essential head tremor. In practice, however, most patients with cervical dystonia experience a combination of these patterns and do not fit easily into one or the other [39]. (See 'Differential diagnosis' below.)
Pain — Pain is a very common feature of cervical dystonia and a major driver of disability [40]. In various series, approximately 75 percent of patients report neck pain [8,38,40]. This contrasts with most other focal dystonias and ET, which tend to be nonpainful.
The pain associated with cervical dystonia is most often local, in the neck itself. Approximately one-third of patients have radicular pain radiating from the neck into the shoulder and arms [7]. Neck pain is more common in patients with neck spasms and sustained, severe head-turning [8].
Pain related to cervical dystonia usually responds to BoNT injections. Neck pain that is constant, severe, disproportionate to the magnitude of the dystonic movements, and refractory to BoNT injections should be evaluated for alternative causes. (See "Evaluation of the adult patient with neck pain".)
The etiology of pain in cervical dystonia may be multifactorial, with both peripheral (musculoskeletal) and central components [40,41]. In one study, laser evoked potentials demonstrated a reduced conditioned pain modulation response, suggesting that the endogenous inhibitory pain system is dysfunctional in patients with cervical dystonia [40].
Sensory trick — A sensory trick, known as "geste antagoniste," is a voluntary maneuver that temporarily reduces the severity of dystonic posturing or movements. A sensory trick is classically associated with cervical dystonia, and its presence confirms the diagnosis of dystonia. It is particularly helpful in cases in which it is unclear whether neck symptoms are due to cervical dystonia or another movement disorder or neck pathology. (See 'Differential diagnosis' below.)
Not all patients with cervical dystonia recognize the presence of a trick, and patients may have one or more tricks, each providing different degrees of symptomatic relief. Tricks in cervical dystonia often simply involve touching a certain area of the head or face. Other patients perform a forceful counter-pressure in opposition to the dystonic head turn, in what is known as a "forcible trick."
Associated dystonia syndromes — Most cases of cervical dystonia in adults are isolated and sporadic, and patients often lack a family history of dystonia, tremor, or other neurologic diseases. Rarely, patients may present with syndromes in which cervical dystonia is either the salient feature (see 'Genetic' above) or a component of a syndrome associated with more widespread (often segmental or generalized) dystonia, other movement disorders, or other neurologic comorbidities.
●Tardive cervical dystonia – Patients with tardive cervical dystonia due to dopamine receptor blocking agents often exhibit dystonia elsewhere in the body (trunk, oromandibular) as well as choreiform movements of the lower face, tongue, hands, and feet. (See 'Acquired' above.)
●Meige syndrome – Meige syndrome is an adult-onset, segmental cranial dystonia. Patients often develop blepharospasm that spreads caudally to involve the mouth and jaw. Occasionally, dystonia spreads extracranially to involve the cervical and limb musculature. Most cases of Meige syndrome are idiopathic [42].
●Dopa-responsive dystonia (DRD) – Cervical dystonia in adults is infrequently due to DRD, which is caused by dopamine deficiency resulting from variants in several enzymes of the dopamine synthetic pathway. Patients exhibit exquisite symptomatic improvement with low doses of levodopa.
Although DRD most often causes childhood-onset dystonia and/or parkinsonism, rare cases with predominant cervical dystonia in older children and young adults have been reported [43,44]. One of the cases was due to a novel mutation in the GTP cyclohydrolase 1 (GCH1) gene [43]. In the other series, four patients from two unrelated families with young-onset cervical dystonia demonstrated robust and sustained improvement with modest levodopa doses, without the development of parkinsonism, dyskinesias, or progression in dystonia after years of follow-up [44]. Genetic testing for GCH1, tyrosine hydroxylase (TH), and sepiapterin reductase (SPR) was negative.
These reports illustrate the importance of considering undiagnosed DRD in cases of cervical dystonia, particularly since it is a treatable condition. DRD is reviewed in more detail elsewhere. (See "Etiology, clinical features, and diagnostic evaluation of dystonia", section on 'Dopa-responsive dystonia'.)
●X-linked dystonia-parkinsonism (XDP) – XDP (also known as DYT-TAF1, DYT3, or Lubag dystonia) is a neurodegenerative condition that mainly affects individuals from the island of Panay, in the Philippines. Patients usually present in their late thirties with severe, progressive dystonia followed by the eventual development of parkinsonism [45]. Dystonia is often focal at onset but generalizes within four years to involve the craniofacial and cervical segments, arms, legs, and trunk [46]. (See "Etiology, clinical features, and diagnostic evaluation of dystonia", section on 'Dystonia-parkinsonism'.)
●Myoclonus-dystonia – Myoclonus-dystonia is a mixed movement disorder syndrome in which myoclonus is often the main and most disabling feature. Subcortical myoclonus is present at rest, during action, and with posture [47]. Some patients exhibit dystonia with an axial (mostly cervical) distribution, while others have segmental, limb, or laryngeal dystonia. Many, but not all, cases are due to pathogenic variants in the sarcoglycan epsilon (SGCE) gene. The syndrome is inherited in an autosomal-dominant fashion, and the gene is maternally imprinted. (See "Classification and evaluation of myoclonus", section on 'Myoclonus-dystonia'.)
DIAGNOSIS
Clinical diagnosis — Cervical dystonia is a clinical diagnosis that should be considered in patients presenting with the insidious onset of an abnormal neck posture in adulthood, often with associated pain and neck tremor. The diagnosis is made by neurologic examination demonstrating the abnormal neck posture (figure 1) along with hallmarks of dystonia (eg, sensory trick, head tremor with directionality).
The International Parkinson and Movement Disorder Society Dystonia Study Group published updated diagnostic criteria for isolated cervical dystonia in 2023 [48]. Although primarily designed for clinical research, these revised criteria can also be applied in clinical settings. The criteria distinguish between probable and definite cervical dystonia based on supportive criteria and exclusion of confounding factors. Brain and spine imaging are not part of the diagnostic criteria.
History — The history helps to exclude alternative diagnoses, identify acquired causes (eg, tardive dystonia), and differentiate isolated cervical dystonia, which is most often idiopathic and sporadic, from combined dystonia syndromes.
●How old is the patient? – Cervical dystonia usually affects adults in their thirties to fifties. Earlier-onset cases are more likely to be genetic or part of a combined dystonia syndrome. (See 'Clinical presentation' above and 'Associated dystonia syndromes' above.)
●How long has the dystonia been present? – Cervical dystonia often has an insidious onset. Old pictures of the patient and questioning of family members may indicate a longer duration of neck postural abnormalities or neck tremor than first reported. Acute onset is generally inconsistent with cervical dystonia and suggests an alternative etiology. (See 'Differential diagnosis' below.)
●Is there a family history? – Most cases of cervical dystonia are sporadic. Rare cases of isolated cervical dystonia are familial (see 'Genetic' above). A genetic etiology is more likely with younger onset and in patients and families with combined dystonia syndromes. (See 'Associated dystonia syndromes' above.)
●Is dystonia the only abnormal movement present? – Most cases of cervical dystonia happen in isolation. The presence of other abnormal movements would suggest dystonia is emerging in the context of a larger movement disorder. Examples include the presence of bradykinesia, which would suggest cervical dystonia is part of a parkinsonian syndrome, or the presence of myoclonus, which would suggest a diagnosis of myoclonus-dystonia. (See 'Associated dystonia syndromes' above.)
●Is there a sensory trick? – Recognition of a sensory trick, although not universally present, can help discern cervical dystonia from its mimics. At times, patients may be unaware that they have a trick, and they should be asked about different gestures or tactile stimuli that improve their dystonic symptoms. (See 'Sensory trick' above.)
●Is there a history of medication exposure? – Past or present exposure to a dopamine receptor blocking agent (eg, first- or second-generation antipsychotics, metoclopramide, prochlorperazine) suggests a tardive etiology. (See 'Acquired' above.)
Neurologic examination — Patients with suspected cervical dystonia should undergo a detailed movement disorder examination to identify the hallmarks of cervical dystonia. These are not always obvious, and special techniques may be necessary to elicit them.
●Position the patient – Patients should be seated in a chair with shoes and socks removed and feet flat on the floor. Sleeves and/or pants should be rolled up so that the forearms and calves are fully exposed. The arms should rest on the armrests or lap.
●Observe the patient at rest – Once positioned, ask the patient to close their eyes and to let the neck drift into its most comfortable position. During this maneuver, look for any rotation, tilting, flexion, extension, or shift of the craniocervical region that may not be present with the eyes open. Be vigilant for the emergence of any neck tremor. The neck should be inspected and/or palpated to detect any muscle hypertrophy.
●Examine neck range of motion and neck tremor – Ask the patient to open their eyes and to demonstrate the range of motion of the neck, including rotation in either direction, tilting to both sides, anterior flexion, and hyperextension. During these maneuvers, notice any limitation in range of motion, which can develop over time due to orthopedic changes of the cervical spine triggered by the constant neck movements.
Patients with dystonic neck tremor will often exhibit the phenomenon of directionality, that is, a net direction in which the neck tends to posture. Positioning of the neck in this direction will often improve (or abate) any neck tremor; this is known as the null point. Positioning the neck away from this direction can exacerbate tremor. This change in tremor severity is characteristic of cervical dystonia and is not a phenomenon observed in essential tremor (ET) of the neck.
●Examine the patient in motion – Next, ask the patient to perform rapid alternating movements of the arms and legs, to walk, and to write. Pay close attention to the neck during these activities, as activation of the limbs often worsens dystonia at the neck. This is known as an overflow phenomenon, and it is pathognomonic of dystonia.
●Elicit sensory tricks – Have patients demonstrate all sensory tricks that they may have become aware of over time. (See 'Sensory trick' above.)
●Look for overflow and other movement abnormalities – Throughout the examination, look for overflow in other body areas. Overflow can be subtle, with movements that include lip-pursing, tongue protrusion or flexion, and extension or adduction of the fingers or toes. Look for the emergence of dystonic movements elsewhere in the body, particularly in the cranial, laryngeal, and brachial regions, and for any signs of associated movement disorders (eg, parkinsonism, myoclonus, and tremor).
Indications for additional testing — Imaging and other ancillary tests are rarely necessary. Their role is to exclude secondary causes rather than to confirm a clinical diagnosis of cervical dystonia.
●Neuroimaging – Magnetic resonance imaging (MRI) of the brain and spine should be obtained in patients with abnormal neurologic examination findings (aside from cervical dystonia and associated head/arm tremor) or atypical clinical features (eg, failure to improve with sleep, severe pain, headaches, nausea, or vertigo). In a study of 25 patients with abnormal neck posturing due to structural causes, most cases were associated with lesions of the brainstem and/or cerebellum (44 percent) [49]. Other lesions were found in the cervical spinal cord and basal ganglia. (See 'Differential diagnosis' below.)
●Bloodwork – Testing for Wilson disease is generally advised in patients presenting with dystonia who are younger than 50 years of age. Testing consists of serum ceruloplasmin and a slit lamp examination. However, in a study of over 1000 patients presenting with cervical dystonia, no cases of Wilson disease were identified [50]. (See "Wilson disease: Clinical manifestations, diagnosis, and natural history", section on 'Diagnostic evaluation'.)
●Genetic testing – Genetic testing should be considered for patients with a family history of dystonia, young-onset cervical dystonia, or dystonia that is part of a larger movement disorder syndrome. (See 'Associated dystonia syndromes' above.)
The modality of testing varies depending on the history. Patients with a family member with a known pathogenic variant in a gene can be tested for the specific variant. Others should be screened more broadly by ordering a panel of genes known to cause dystonia. Whole-exome sequencing can be performed to search for variants even outside of the genes known to increase the risk for dystonia.
Individuals planning on having children can greatly benefit from knowing whether they carry a heritable, disease-causing mutation, but recognition of a genetic diagnosis also allows for the identification of other gene carriers within a given family, opens the possibility of eligibility for clinical trials, and helps to predict response to deep brain stimulation (DBS).
DIFFERENTIAL DIAGNOSIS — Cervical dystonia is a relatively rare condition. There are many other causes of abnormal neck posturing and tremor that are more common.
●Essential tremor (ET) involving the neck – ET is a common cause of head tremor, especially in older adults. Although ET usually begins in the hands and is therefore already apparent when head and/or voice tremor appears, some patients with ET have early or more prominent head tremor. Such patients can appear similar to those with cervical dystonia who have prominent neck tremor and very subtle or mild neck posturing.
By definition, a diagnosis of ET requires hand tremor, and patients with isolated head tremor who fail to develop hand tremor over time most likely have cervical dystonia rather than ET. In a cohort of nearly 600 patients with ET, less than 3 percent of patients had head tremor with mild hand tremor, and no cases of isolated head tremor were identified [51].
On the other hand, hand tremor does not always indicate ET, as patients with cervical dystonia can also have hand tremor. In patients with both head and hand tremor, the neck should be carefully examined for range of motion and muscle hypertrophy. Patients with ET should have good range of neck motion, no muscle hypertrophy, and no dystonic features to their tremor, such as directionality, a sensory trick, or a null point. (See 'Neurologic examination' above.)
Other features that may point more towards ET in a patient with both hand and head tremor are older patient age (>60 years) [52], a mixed "yes-yes" and "no-no" directionality to the head tremor [53], and lack of awareness of the tremor (tremor agnosia) [54]. None of these features is definitive in isolation, however. Clinical features and diagnosis of ET are reviewed in detail separately. (See "Essential tremor: Clinical features and diagnosis", section on 'Clinical features'.)
●Cervical tics – Motor tics of the neck can be difficult to distinguish from cervical dystonia with fast neck tremor. The presence of persistent posturing and the absence of a sense of urge and/or relief when the movements take place would be supportive of dystonia [48].
●Anterocollis in parkinsonian syndromes – Anterocollis is defined as anterior neck flexion of more than 45 degrees that results from dystonia of the neck flexors, weakness of the neck extensors, or both (figure 2). Patients rarely present with isolated anterocollis; most commonly, it is observed in the context of Parkinson disease (PD) and other parkinsonism disorders, particularly multiple system atrophy [55,56]. (See "Multiple system atrophy: Clinical features and diagnosis", section on 'Motor involvement'.)
Anterocollis has also been reported as a reversible side effect of dopamine agonist use in patients with PD [57], as an "off" symptom in PD [55], or as a manifestation of comorbid myasthenia gravis with neck extensor weakness [58].
Anterocollis is notorious for its refractoriness to treatment. However, it has been described as a phenomenon responsive to levodopa and subthalamic nucleus (STN) deep brain stimulation (DBS) in a patient with PD [55]. (See "Device-assisted and lesioning procedures for Parkinson disease".)
●Orthopedic cervical spine changes – Congenital or acquired (degenerative or traumatic) changes of the cervical spine, ligaments, or musculature can lead to abnormal head posturing and pain. Depending on the severity of the spine changes, limitations in passive range of motion may resemble dystonia [59]. A careful neck examination is key in such cases; patients with a primary orthopedic problem will not have any phasic neck movements, tremor, or other dystonic features. (See 'Neurologic examination' above and "Evaluation of the adult patient with neck pain".)
●Dropped head syndrome – Dropped head syndrome is defined by neck extension weakness that causes a chin-on-chest deformity without limitation in passive neck extension. Patients often describe cervicalgia, feeding difficulties, and difficulty with horizontal gaze. A systematic review of 129 published cases identified four main causes: isolated neck extensor myopathy (32 percent), PD (20 percent), myasthenia gravis (12 percent), and amyotrophic lateral sclerosis (7 percent) [60]. Of note, most patients were over age 60 years and female. (See "Evaluation of peripheral nerve and muscle disease" and "Diagnosis of myasthenia gravis".)
●Functional neck movements – Patients with functional movement disorders may exhibit abnormal neck movements either in isolation or in the presence of abnormal movements elsewhere in the body. It can be difficult to distinguish functional from organic dystonia, but features that often suggest a psychiatric etiology include sudden symptom onset that is often maximal at onset, presence of fixed dystonia, severe pain, variable phenomenology of neck movements, distractibility of neck movements, and entrainment of neck tremor. Patients with functional neck movements may describe sudden cessation of symptoms during certain activities or circumstances, which should not be mistaken for a sensory trick. (See "Functional movement disorders", section on 'Clinical features'.)
Of note, patients with rapid-onset dystonia-parkinsonism (RDP, DYT12) can experience new-onset dystonia of the craniocervical region over hours or days and should not be misdiagnosed as functional. Genetic testing can confirm the diagnosis.
●Compensation for visual and oculomotor disturbances – Patients with fourth nerve palsies develop a compensatory head tilt that is contralateral to the impaired trochlear nerve. The tilt corrects the vertical diplopia that results from the nerve palsy [61]. Unlike patients with cervical dystonia, the tilt can be reduced at will, unless the patient has developed fixed orthopedic changes of the cervical spine from decades of abnormal head posturing. Some experts suggest that all patients with new-onset laterocollis should be screened for extraocular movement abnormalities that may be amenable to prismatic correction [61]. (See "Fourth cranial nerve (trochlear nerve) palsy".)
Similarly, patients with homonymous hemianopia may adjust the position of their head and eyes to ensure that visual targets remain within their visual field, while those with nystagmus may exhibit head shaking, especially when focused, which can synchronize with the nystagmus in terms of waveform and direction [48]. Patients with oculomotor apraxia who have difficulty initiating saccades may exhibit head thrusting that can mimic dystonic head turning.
●Childhood syndromes featuring abnormal head posturing – Several nondystonic conditions in infants can mimic cervical dystonia. Congenital muscular torticollis is a condition characterized by sustained abnormal head posturing in infants due to shortening and fibrosis of specific neck muscles [48]. Another example is benign paroxysmal torticollis, which is a self-limited migraine equivalent that involves episodic neck posturing with autonomic features, irritability, ataxia, apathy, and drowsiness.
Atlantoaxial subluxation, which occurs primary in children, is a rotation of the atlantoaxial complex that is then held in a fixed position. It happens acutely because of a muscle spasm or due to mechanical obstruction to reduction. Clinically, patients present with new-onset painful neck posturing, in sharp contrast to the often insidious onset of isolated cervical dystonia. Many causes have been described, including trauma, infections, inflammation, and autoimmunity. Urgent neck imaging is required for diagnosis. The treatment is largely conservative, although traction and cervical reduction are occasionally necessary [62]. (See "Spinal column injuries in adults: Types, classification, and mechanisms" and "Acquired torticollis in children".)
Other childhood syndromes featuring abnormal neck posturing include Sandifer syndrome (in which the abnormal neck movements are caused by reflux) and spasmus nutans, a typically benign condition featuring nystagmus and compensatory head nodding [48]. (See "Pendular nystagmus", section on 'Spasmus nutans'.)
●Spinal cord tumors – Sudden-onset, nontraumatic, nondystonic neck posturing has been reported as a symptom (and, at times, the presenting symptom) of posterior fossa and cervical spinal cord tumors in children. It is hypothesized that pressure on the accessory nerve or stretching of the dura may be the cause of the posturing [63]. Similarly, paroxysmal, daytime-only, painless neck posturing has been reported as a manifestation of a high cervical spinal cord lesion in an adult [64]. If not present initially, the emergence of myelopathic signs (hyperreflexia, hypertonia, weakness, and/or incontinence, among others) should prompt neuroimaging.
●Bezold abscess - Bezold abscess is a rare condition in which a deep neck abscess develops as an intratemporal complication of coalescent mastoiditis through direct extension into the perimastoid tissues. While neck pain and stiffness may be reminiscent of cervical dystonia, associated symptoms such as fever, swelling, otalgia, and hearing loss are red flags that should bring this diagnosis into consideration [48]. (See "Deep neck space infections in adults".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Dystonia in children and adults".)
SUMMARY AND RECOMMENDATIONS
●Definition – Cervical dystonia is an adult-onset focal dystonia characterized by abnormal neck posturing, neck tremor, and neck pain. Patients may also manifest a sensory trick, which is a tactile maneuver (eg, touching the face in a certain area) that leads to improvement in dystonic symptoms. (See 'Clinical features' above.)
●Epidemiology – Cervical dystonia is more common in females than males and typically develops between the fourth and sixth decades of life. (See 'Epidemiology' above.)
●Etiology – The majority of cases are idiopathic and sporadic. Rare monogenetic forms of isolated cervical dystonia exist. Tardive cervical dystonia due to exposure to dopamine receptor blocking agents is an acquired form usually but not always accompanied by oro-bucco-facial dyskinetic movements. (See 'Etiology' above.)
Cervical dystonia is likely a network disease affecting function of a central head neural integrator, with inputs from the frontoparietal cortex, basal ganglia, brainstem, cerebellum, and cervical muscle spindles. (See 'Pathogenesis' above.)
●Clinical features – Abnormal neck posture is the defining feature of cervical dystonia. Postures are described based on the plane and direction of displacement of the neck and head. Torticaput and laterocaput are the most common forms (figure 1). (See 'Neck posturing' above.)
Symptom onset is typically gradual and insidious. Diagnostic delays are common, and clinicians may fail to recognize mild neck posturing in patients presenting with neck pain or tremor. (See 'Clinical presentation' above.)
●Diagnosis – Cervical dystonia is a clinical diagnosis based on typical signs and symptoms, and a detailed movement disorder examination is critical. Examiners should position the patient properly, observe the patient carefully at rest and in motion, and actively search for the presence of directionality, jerkiness, overflow, and a sensory trick, all of which strongly suggest dystonia. (See 'Neurologic examination' above.)
●Imaging – Brain and cervical spine magnetic resonance imaging (MRI) should be performed in patients with atypical clinical features or abnormal neurologic examination findings (aside from cervical dystonia and associated neck/arm tremor). Genetic testing is done selectively and primarily in patients with combined dystonia syndromes or a family history. (See 'Indications for additional testing' above.)
●Differential diagnosis – The differential diagnosis of cervical dystonia includes essential tremor (ET) with neck tremor, parkinsonism, orthopedic changes of the cervical spine, dropped head syndrome, atlantoaxial subluxation, trochlear nerve palsy, and spinal cord tumors. (See 'Differential diagnosis' above.)
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