A chronic neurological movement disorder that causes extreme pain in the neck is called spasmodic torticollis. It causes the neck to turn involuntarily to up, down, left or right movement. Spasmodic torticollis disorder is also known as “cervical dystonia.” Both antagonist and agonist muscles simultaneously contract during a dystonic movement. Causes of this disorder are usually idiopathic. There are some patients who develop the disorder because of another disease or disorder. Most patients also experience the symptoms once they reach middle age. The best way to treat spasmodic torticollis is through using botulinum toxin type A but make sure to consult your physician first.S
Signs and Symptoms of Spasmodic Torticollis
The symptoms of spasmodic torticollis are mild. Some patients usually feel some kind of tremor in their heads for a couple of months at the onset. This is followed eventually by a prolonged involuntary position, or the head may tilt, turn, pull and do some jerky movements. The involuntary spasm of the neck muscles over time will increase in strength and frequency until it reaches sort of a plateau. Symptoms can become worse while the person is walking or during periods of extreme stress. Other symptoms usually include tremor, neck pain, muscle hypertrophy, and dysarthria. Studies have shown that out of 75% of patients who report neck pain, about 40% experience head tremor.
Pathophysiology of Spasmodic Torticollis
The pathophysiology of spasmodic torticollis is still relatively unknown. Spasmodic torticollis is also considered as neurochemical in nature, and it usually doesn’t result in any structural neurodegenerative changes. When it comes to primary spasmodic torticollis no lesions are present in the basal ganglia. PET and fMRI studies have also shown that there are abnormalities in the hyperactivation and basal ganglia of the cortical areas.
Studies have suggested that there’s a functional imbalance in the striatal control of the globus pallidus, specifically the substantia nigra pars reticulate. The studies hypothesize that the hyper activation of the cortical areas are primarily due to reduced pallidal inhibition of the thalamus which leads to the over activity of the pre – frontal and medial cortical areas and under activity of the primary motor cortex during the movement of muscles. Studies of local field potentials have also shown an increase of 4-10 Hz oscillatory activity in the globus pallidus internus during myoclonic episodes and an increase of 5-7 Hz activity in dystonic muscles when compared to other primary dystonias. This indicates that oscillatory activity in these frequency bands may be involved in the pathophysiology of spasmodic torticollis.
Studies also suggest that the imbalance of neurotransmitters is the cause of functional imbalance. Neuro – transmitters such as acetylcholine, gamma-aminobutyric acid, and dopamine. These neuro – transmitters travel to the muscle groups in the neck from the basal ganglia. An increase in neuro – transmitters causes spasms to occur in the neck area which results to spasmodic torticollis.
Diagnosis of Spasmodic Torticollis
If you want to measure the severity of spasmodic torticollis, the most commonly used scale is called the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). It has also been shown that this rating system has interobserver reliability, and it’s also used in clinical trials and had been widely accepted. There are 3 scales in the TWSTRS that are used to represent the severity of the condition and the pain being experience when patients have spasmodic torticollis:
- Torticollis severity scale
- Disability scale
- Pain scale
Classification of Spasmodic Torticollis
Spasmodic torticollis is a form of a neuromuscular disorder or focal dystonia that consists of sustained muscle contractions causing which causes twisting and repetitive movements as well as abnormal postures in a single body region.
There are two categories of spasmodic torticollis: the cause, and the age of onset. If the patient is diagnosed before he/ she reaches 27 years old, then the disorder is categorized as the early onset. The causes can be identified as either idiopathic (primary), or symptomatic (secondary). Spasmodic torticollis can also be further categorized by the direction and rotation of one’s head movement.
Primary spasmodic torticollis is an occasional tremor in the neck and it’s also having no abnormality other than dystonic movement. This type of spasmodic torticollis is usually hereditary. Studies have shown that the DYT7 locus on chromosome 18p in a German family and the DYT13 locus on chromosome 1p36 in an Italian family is associated with torticollis. The inheritance for both loci is autosomal dominant. These loci are all autosomal dominantly inherited with reduced penetrance. Although these loci have been found, it is still not clear the extent of influence the loci have on spasmodic torticollis.
Secondary torticollis is diagnosed when any of the following are present:
- History of exogenous insult or exposure
- Neurological abnormalities other than dystonia
- Abnormalities on brain imaging in the basal ganglia.
If other conditions lead to torticollis, then it can be considered secondary torticollis. A variety of conditions can cause brain injury, from external factors to diseases such as the following:
- Perinatal (during birth) cerebral injury
- Cerebrovascular diseases
- Central nervous system tumor
- Peripheral or central trauma
- Infectious or post infectious encephalopathies
- Paraneoplastic Syndromes
- Central pontine Myelinolysis
Treatment for Spasmodic Torticollis
There are various treatments available; the most commonly used is the botulinum toxin injections in the dystonic muscle of the neck. Other treatments may include oral medications, deep brain stimulation, and sensory trick for a mild occasional twinge. A combination of these things was used to control torticollis. Selective surgical denervation of nerves that triggers muscle contractions are also used to offer patients relief from pain and spasms as well as limit the damage to their spine as a result of torque posture. Spinal fibrosis which is the locking of spinal facets due to muscular contortion resulting in fused vertebrae may occur rapidly. This is why it is important to seriously evaluate the option of surgical denervation as soon as possible.