Adult torticollis, also referred to as cervical dystonia or spasmodic torticollis, is a condition in which the muscles that control the neck are locked into a sustained involuntary contraction. These contractures can commonly cause twisting, repetitive movements, or abnormal posturing of the neck. Depending on the severity, it can be a very painful condition that may lead to a great deal of distress. Presentations of torticollis are defined using causal terms such as acute, congenital, chronic, aquired, idiopathic, or secondary. [1][2]
Epidemiology/Etiology:
Idiopathic cervical dystonia (ICD) is the most common form of adult-onset focal dystonia. The prevalence of dystonia is difficult to ascertain. On the basis of the best available prevalence estimates, primary dystonia may be 11.1 per 100,000 for early onset cases in Ashkenazi Jews from New York area, 60 per 100,000 for late onset cases in Northern England, and 300 per 100,000 for late onset cases in the Italian population over age 50. The chart in figure 1 displays that most of the cases were reported in the age group of 31 to 40 years of age, which indicates the prevalence of adult-onset idiopathic cervical dystonia.[3][4][5]
This common disorder is characterized by involuntary muscle contractions in the neck musculature; however, the pathogenesis is unknown in most of the cases. Although the pathogenesis is idiopathic, two causes have been hypothesized and have been extensively researched, and there has been clear evidence that they play a role in the onset of adult-onset focal dystonia. These two causes are:
• Genetics:
There are three observations that support the hypothesis that an abnormal gene is responsible for a proportion of ICD.[6]These hypotheses are as follows: (i) In families with childhood-onset idiopathic torsion dystonia, for which a genetic basis has been established, family members may have focal cervical or segmental dystonia (ii) It has been recognized since 1896 that torticollis may affect siblings, and adult-onset torticollis may affect multiple generations (iii) A significant percentage of first degree relatives of patients with focal dystonia have focal dystonia or tremor, and in families of patients with ICD, the prevalence of focal dystonia is higher than expected.
• Trauma:
The prevalence of patients with cervical dystonia related to trauma is 5-21%.[2] Injuries sustained as a result of trauma had immediate pain followed by the onset of cervical dystonia with near total neck immobility within a few days. There was no morning relief and the dystonia persisted during sleep. The presence of cervical dystonia persisted for up to four years after follow-up and responded poorly to medications and botulinum toxin. It is important to note that none of the patients who sustained trauma had a family history of dystonia.
Another possible cause of ICD that has been researched is abnormalities in the brain structures. A conventional MRI Class IV study T2 bilateral abnormalities in the lentiform nucleus in ICD. However, the abnormalities were only detected on calculated T2 values; no obvious signal changes could be recognized on visual inspection of T2-weighted images. Structural changes in the lentiform nuclei, predominantly in the contralateral pallidum in patients with adult-onset focal dystonia, have been suggested by increased echogenicity of these structures on transcranial sonography.
Causes :
Spasmodic torticollis results from abnormal, excessive brain input to muscles. Nerve cells (neurons) within the brain act together in a variety of networks to affect different functions, including voluntary movement. Though the exact mechanism producing spasmodic torticollis and other dystonias isn’t known, the most likely cause stems from abnormal electrical activity within neurons in the cerebral cortex or in the basal ganglia — a collection of nerve cells deep in the brain — or in both, which make up a key network for voluntary movement.
Electrical activity between neurons is modulated by various chemicals known as neurotransmitters. Some of these neurotransmitters are :
• GABA. Gamma-aminobutyric acid (GABA) decreases the electrical activities of nerve cells and helps the brain maintain muscle control.
• Dopamine. Like GABA, this neurotransmitter helps the brain maintain muscle control by preventing neurons from firing (inhibitory neurotransmitter).
• Acetylcholine. This neurotransmitter works in a way that is the opposite of GABA and dopamine by helping initiate movement. Acetylcholine, released at nerve endings, causes muscles to contract.
• Norepinephrine, serotonin. These neurotransmitters work by causing blood vessels to narrow or constrict. Norepinephrine works in the involuntary (sympathetic) nervous system and is released during times of stress. Serotonin regulates the delivery of messages between nerve cells. Both of these neurotransmitters help the brain regulate acetylcholine.
Primary vs. secondary torticollis:
Your doctor may classify your type of spasmodic torticollis as primary or secondary based on its cause.
• Primary spasmodic torticollis.
This type of torticollis is described as not being secondary to any identifiable, acquired disorder affecting the brain or spinal cord — such as a stroke, infection, tumor or trauma. Some people with primary spasmodic torticollis appear to have inherited a gene linked to dystonia (DYT1). However, not every person carrying the DYT1 gene will develop dystonia. Therefore, it’s likely that other genes or environmental factors may play a role in the development of dystonia.
• Secondary spasmodic torticollis.
Torticollis that occurs as a consequence of, or secondary to, a specific injury to the brain or spinal cord, such as from stroke, tumor, severe trauma, toxins or birth injury, is called secondary spasmodic torticollis. There may be a period of months between the injury and the onset of the dystonia. Because the development of torticollis (particularly after trauma) may vary among people with identical injuries, experts believe that a genetic predisposition may also play a role.
Some cases of secondary dystonia, including spasmodic torticollis, are caused by a malfunction in the production of dopamine. Dystonia may also be a sign of other neurological diseases, such as Parkinson’s disease or Wilson’s disease.
Encephalitozoonosis:
Encephalitozoon cuniculi is a protozoan (single-celled) parasite that infects the kidney and brain. It causes inflammation of the brain (meningoencephalitis) and can result in paralysis anywhere in the body. In addition to head tilt, you may also see behavior changes, staggering, and seizures. It is transmitted through the urine. The onset of signs of infection with E. cuniculi are frequently gradual. There is a blood test for antibodies to E. cuniculithat can determine whether a rabbit has been exposed. Unfortunately, a positive test is not diagnostic since many (up to 80%) of rabbits may test positive for this parasite.
The treatment of E. cuniculi infections includes certain wormers including albendazole, fenbendazole and oxibendazole along with dexamethasone or other corticosteroid.
Ascarid migration (cerebral larval migrans):
The raccoon roundworm, Baylisascaris procyonis, can infect the brain of many mammals including dogs, rabbits, and humans. The migrating larvae of the worm cause damage and inflammation in the brain. It is extremely difficult to positively diagnose this disease until a post-mortem examination can be performed.
There is no specific treatment for infection with B. procyonis. Again, corticosteroids may be given along with supportive care
.
Toxins:
Several toxins can cause neurological signs, including head tilt. These include heavy metals such as lead and zinc which may be found in paint, the welds in cages, and pottery. Exposure to certain insecticides can result in toxicity with head tilt being a common sign. Certain plants and mushrooms are toxic to rabbits and can also affect the nervous system. If the liver is diseased, toxins such as ammonia can build up in the bloodstream and cause neurologic signs.
Treatment of toxicities depends upon the specific toxin. For heavy metal poisonings, chelation therapy aids in removing the lead from the body. Chelation agents include succimer (DMSA), dimercaprol (BAL), calcium EDTA, and penicillamine. Thiamine (vitamin B1) may also be given. External exposure to a pesticide is treated by repeatedly bathing and rinsing the rabbit and providing supportive care. Liver disease may be treated with medications and diet changes.
Stroke:
Strokes, or cerebrovascular accidents, are not as common in pets as they are in humans. Diagnosis of a stroke is difficult, often requiring sophisticated imaging techniques such as CAT scans, or MRIs. The diagnosis in animals is often made by ruling out other causes of the signs of disease.
There is no specific treatment for a stroke. Heparin may be administered, and supportive care given in the form of fluids, assisted feedings, and pain medication. Depending upon the extent of the brain damage, the rabbit may partially recover over a period of weeks.
Trauma:
Injury to the brain or neck may result from a blow to the head, a fall, or other trauma. It may also cause bleeding in the middle or inner ear. The extent of the signs depends upon the extent of the damage.
Brain or ear trauma is generally treated with supportive care. Medications may be used to decrease the swelling in the brain.
Mite infestation:
Rabbits are prone to infection with the rabbit fur mite, Cheyletiella parasitovorax, which can also affect the ears. Ear mite infestations alone would rarely cause head tilt, but if severe, can lead to bacterial ear infections which are a common cause of head tilt.
Mite infections are often treated with ivermectin. Secondary bacterial infections would need to be treated with antibiotics.
Cancer:
Cancer of the brain or ear is rare in rabbits, but it can occur and result in signs including head tilt.
There generally would be no treatment for this type of cancer other than supportive care.
Nutritional imbalances:
Abnormal levels of vitamins A, B, and/or E can produce neurologic effects, as can mineral imbalances, e.g.; selenium and copper.
Treatment would be primarily based on correcting the imbalance through dietary changes and supplements. Supportive care may also need to be provided
Symptoms :
A major sign of spasmodic torticollis is spasms in your neck muscles that you can’t control. These spasms may be quite painful and even produce compression of nerve roots in the neck
.
Torticollis literally means “twisted neck.” However, cervical dystonia may produce abnormal neck
postures in different directions. Frequently, there is a combination of these abnormal postures in any given person with torticollis.
• Anterocollis, in which your head tilts forward
• Retrocollis, in which your head tilts backward
• Laterocollis, in which your head tilts to one side
Additional signs and symptoms include :
• Enlargement of neck muscles (possibly present at birth)
• Uneven shape of an infant’s head from sleeping on the affected side
• Elevation of the shoulder on the affected side
• Stiffness in the neck muscles
• Limited range of motion
• Headache
• Neck pain
• Tremor
In young children, spasmodic torticollis can occur in a couple of forms. Both involve the large neck muscle that runs from behind the ear to the joint between the collarbones (sternocleidomastoid muscle).
• Congenital muscular torticollis:
Signs and symptoms of this form of torticollis usually develop in infants by the time they are 2 to 4 weeks old. Your child will prefer to hold his or her head to one side, almost always tilted toward the muscle in spasm. Often there will be a lump or mass in the affected neck muscle, which may be the first sign of congenital muscular torticollis in children between 1 and 8 weeks old. The mass usually goes away by the time your child is about 6 months old. He or she may also have additional muscular or skeletal problems, such as hip dysplasia, irregular facial features and abnormalities in the bones (vertebrae) of the neck (cervical spine).
• Acquired torticollis:
. This kind of spasmodic torticollis is similar to congenital torticollis, but it’s rare. Children are usually older when it first occurs, and the symptoms appear more rapidly. Your child may indicate pain and have a decreased range of motion in the head and neck. Unlike congenital torticollis, the head is almost always tilted away from the muscle in spasm. This difference is often used to distinguish between the two types of torticollis in children.
Differential Diagnosis:
Conditions the physical therapist should consider during initial evaluation and subsequent treatments include, but are not limited to:
• Parkinson Disease:
May present with head in a posture resembling torticollis. Will likely test positive for other nervous involvement. Tremor will be present in a sinusoidal oscillatory pattern. The therapist may also notice unsteadiness of gait, rigidity, and dyskinesia[
• Post-traumatic dystonia:
History of recent trauma to the body region experiencing dystonia. Considered a type of secondary dystonia, onset of symptoms may come immediately after insult, or up to 12 months following. An estimated 5-21% of patients with cervical dystonia have a history of a trauma to the head or neck, although it is unclear whether the insult acted as the “trigger” for the condition.[7]
• Wilson Disease:
Wilson disease is an inherited disorder that can cause an accumulation of copper in the body. For a patient under age 40, with unexplained gradual onset of symptoms, a screen for Wilson disease is indicated.
• Adult-onset idiopathic torticollis: Gradual onset of symptoms, with up to 75% of patients reporting concurrent neck pain. May also present with jerking movements, transient spasms, shoulder elevation, stiffness/tightness, and tremor.[2]
Patients presenting with any form of adult-onset torticollis will ultimately be treated with an impairment based approach.
Examination:
The evaluation of an adult with signs or symptoms of torticollis begins with a thorough history followed by a physical examination[11]:
History:
• Previous episodes of abnormal head posture
• Neck pain
• Headache
• Birth history
• Family history
• Medication history
• Trauma
• Recent infection
Physical Exam:
Vitals:
• Height
• Body weight
• Blood pressure
• Pulse rate
• Respiration rate
• Temperature (if indicated)
Observation in Standing:
Posture:
• Head alignment on cervical spine
• Cervico-thoracic spine
• Scapula
• Glenohumeral joint
• Arm & forearm
• Hand
Soft tissue:
• Muscular atrophy
• Muscular spasms
• Mass in tissue
• Phasic jerking of muscle
• Shape/symmetry of structures BIL
The examination also may include a commonly used outcome measure, the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). This scale includes an assessment of the dystonic position of the head, neck, and shoulders, the effectiveness of sensory cues, the length of time the patient can keep the head in the midline, and the range of head and neck movements.[2]
Neurological Screen:
• Reflexes (C5,C6,C7)
• Myotomes (C4-T1)
• Dermatomes (C4-T1)
Thoracic Provocation Test:
• Seated Rotation BIL
Ligamentous Instability::
• Sharp-Purser
• Alar ligament
Cervical Active Range of Motion Assessment:
• Flexion (45 degrees)
• Extension (75 degrees)
• Lateral flexion (40 degrees)
• Rotation (85 degrees)
Shoulder Active Range of Motion:
• Flexion
• Extension
• Abduction
• Adduction
• Internal rotation
• External rotation
Palpation:
Sitting:
• Upper trapezius
• First rib
• Anterior/posterior rib cage
Supine:
• Sternocleidomastoid (STM)
• C7-C1 cervical paravertebral muscles
• Nuchal line and suboccipital muscles
• Mastoid process
• C1 transverse processes
• C2-C7 spinous processes
• C2/3 through C6-7 articular pillars
*Be sure to note any tenderness due to trigger points and/or abnormal masses found in the surrounding tissues. Take notice to localized spasms and/or tightened musculature. Patient’s involved musculature (especially SCM), will be especially prominent upon palpation.*
Joint Mobility:
Sitting:
• 1st rib (hypo, normal, hyper)
Supine:
• OA (Flexion: 10 degrees, Extension: 25 degrees, Sidebending BIL: 5 degrees)
• AA (Flexion: 8 degrees, Extension: 10 degrees, Rotation: 45 degrees)
• Articular Pillars BIL (Hypo, Normal, Hyper)
Prone:
• Passive Inter-vertebral mobility (bilaterally & unilaterally)
Muscle Length:
• Suboccipital muscles
• Trapezius
• Levator scapulae
• Scalenes
• SCM BIL
*Assessing for muscle imbalances, resistance to passive movements, end feel, and pain. Involved SCM will be extremely resistant to passive length assessment.*
Diagnostic Testing:
Tests are not required to make the diagnosis of adult torticollis, however they can be used to evaluate the integrity of the involved structures. Such diagnostic tests include X-rays, CT scan, and MRI. Lab studies may be useful if infection is suspected as the etiology for torticollis.[2]
Medical Management (current best evidence):
Pharmacologic:
Oral Medications:
Prescription medications provide only modest symptomatic benefit in the treatment of dystonia. The main purpose of oral medication is the avoidance of the causative agents. In early stages of cervical dystonia, medications used in low doses (ex. benzodiazepines, baclofen, or anticholinergic agents) may be useful. Anticholinergic agents were reported to have better outcomes than in those receiving benzodiazepines or baclofen. Side effects may include dry mouth, cognitive disturbances, diplopia, drowsiness, glaucoma, or urinary retention.[2]
Intrathecal Baclofen (ITB):
This intervention has been used most commonly for the treatment of hypertonicity in various clinical populations, where it has been shown to have success. ITB was shown to be effective in treating generalized dystonia, particularly when the catheter was placed above the level of T4. Out of the 77 subjects in one trial that received ITB pumps, subjects had significantly lower dystonia scores — according to the Barry-Albright Dystonia Scale — at 3, 6, 12, and 24 months. 86% of those subjects reported improved quality of life and ease of care.[2]
Botulinum Toxin:
The introduction of chemodenervation with botulinum toxin radically changed the prognosis of patients with idiopathic cervical dystonia.[6] It is the most commonly used pharmacotherapy for overactive and dystonic cervical musculature. Botulinum toxin A provides graded, reversible denervation of the neuromuscular junction by preventing the release of acetylcholine from the presynaptic axon of the motor end plate.[2]This treatment is now the first line therapy for cervical dystonia, but its true efficacy is still unknown.[10] However, botulinum toxin benefits the highest percentage of patients in the shortest amount of time. The most important aspect to consider when administering the botulinum toxin is identification of the sites of pain and the muscles responsible for the abnormal posture. The SCM, trapezius, splenius capitus, and levator scapulae are the most commonly injected sites.[6] A benefit from botulinum toxin is generally seen within the first week, but may rarely be delayed for up to eight weeks. The benefit lasts for an average of twelve weeks and most physicians suggest repeating injections every 3-4 months. Medications are generally used as adjuncts to botulinum toxin, although no trial has sought to demonstrate a synergistic effect. Side effects to this treatment approach may include injection site pain, dysphagia, dry mouth, excessive weakness of the injected or adjacent muscles, and fatigue.[2]
• Drugs that either increase or decrease your dopamine levels.
Dopamine is a neurotransmitter that helps your brain fine-tune muscle movement. People have benefited from drugs that both increase and decrease dopamine levels. Drugs that increase dopamine levels are levodopa (Laradopa), the combination drug levodopa-carbidopa (Sinemet) and bromocriptine (Parlodel). Reserpine is a drug that is used to decrease dopamine levels. Side effects may limit the usefulness of drugs that change your dopamine level and include dizziness, upset stomach, constipation, diarrhea, vomiting, headache, dry mouth and decreased sexual ability. Additionally, levodopa may cause abnormal thinking, including a false sense of well-being and hallucinations, numbness, unusual and uncontrolled movements of the body, fatigue and weakness.
• Anticonvulsants.
These medications — such as carbamazepine (Carbatrol, Epitol), which is usually used to control epilepsy — have occasionally been helpful in treating dystonias. Side effects of these medications may include abnormal behavior, such as agitation, irritation, depression and suicidal thoughts. In addition, anticonvulsants may cause you to lose muscle control, have blurred or double vision, or become drowsy, dizzy, lightheaded or weak. Your skin may also become more sensitive to sunlight.
Surgical:
Selective Peripheral Denervation:
This surgical approach denervates muscles responsible for abnormal movements and reserves innervation to muscles that are noncontributory. According to a study, the surgical outcomes of 260 subjects reported an 88% success rate based on a 4-point scale (poor, fair, very good, or excellent) evaluating the presence or absence of detectable abnormal movements. Muscles selected for denervation should be chosen on the basis of an examination of abnormal movements and confirmation with EMG recording. Patients with pure rotary torticollis with mild extension show the best postoperative results. Side effects may include transient balance problems, transient dysesthesia or sensory loss in denervated posterior cervical segments, wound infection, and dysphagia.[2]
Deep Brain Stimulation (DBS):
The use of DBS of the globus pallidus internus (GPi) or the subthalamic nucleus (STN) was implemented in patients with intractable cervical dystonia. This surgery involves the placement of microelectrodes into the GPi, typically bilaterally, with identification of the GPi and guidance of the microelectrode placement by microstimulation.[2] It has been demonstrated that DBS maintains marked symptomatic and functional improvement in the majority of patients with dystonia for the long term, and it also appears that patients with cervical and generalized dystonia gain similar long-term improvement.[12] One negative aspect of this intervention is that multiple visits are required to properly program the settings for the stimulator, but some advantages to this procedure include the reversibility of the procedure, the ability to adjust the stimulation parameters, and continued access to the therapeutic target. It has also been suggested that DBS reduces the use of oral medications. Side effects include infection, lead fractures, battery failure, and perioral tightness during DBS adjustment visits. No study has taken place that has examined the use of physical therapy as an adjunct to DBS surgery.[2]
Both the deep brain stimulation (DBS) and the selective peripheral denervation groups showed gradual improvement. There was no significant differences between the two interventions, however, DBS may trend towards greater pain reduction.[13]
Physical Therapy Management (current best evidence):
Little research has been done on physical therapy management of adult torticollis. No randomized controlled trials have been conducted, and the studies performed on specific interventions — such as vibration therapy and progressive muscular relaxation — consist of case studies or small sample sizes without control groups. Therefore, management of the adult patient with torticollis will follow an impairment based approach tailored to the individual.[2][6][14][15]
Zetterberg et al conducted an ABA-style case series studying the effects of progressive muscle relaxation, isometric muscle contractions, exercises for improving coordination, balance, and perception, and stretching. Outcome measures were patient quality of life and pain, using the TWSTRS. Patients demonstrated short term benefits from the interventions provided, and regressed when the protocol was halted. Half of the patients regressed to the baseline VAS scores at the 6 month follow-up.[14]
Karnath et al documented the effects of vibratory stimulation on a single patient. Vibration directly to the contracted muscle, with a duration of either 5 seconds or 15 minutes, demonstrated the ability of the muscle to relax, and normal head posture to be assumed. Relaxation times were not documented, but it was reported that the patient was able to maintain a relaxed position for a longer time following the 15 minute treatment.[15]
The primary impairments associated with adult torticollis are decreased range of motion, pain, and problems with postural control. Since torticollis usually involves contractions of the sternocleidomastoid and scalene muscles which perform cervical flexion, lateral flexion, and rotation, antagonist strengthening may improve posture. Strengthening the contralateral sternocleidomastoid and scalene muscles along with the primary neck extensors may aid the patient in achieving proper head position. If the patient has been in the contracted position for a long period of time stretching accompanied with relaxation techniques may help restore natural muscle length. If this causes an increase in pain or does not yield positive results refrain from this intervention. Given that mobilization is widely accepted intervention for general cervical pain, this may be an effective technique for pain modulation in this patient population. However, since impairment based approach focuses on the individual needs of the patient, the therapist will need to determine if the patient is able to relax sufficiently to benefit from mobilization. Palliative interventions may also include soft tissue mobilization at the therapist’s discretion.
