Torticollis may be either:
- Dystonic Torticollis
- Non-dystonic or Pseudodystonia
Primary focal dystonia presents as sustained involuntary contractions of the neck muscles leading to abnormal movement and posture of the head.
Further, Dystonic Torticollis is of the following types –
1. Primary / Idiopathic Spasmodic Torticollis:
A chronic, progressive form of torticollis. It is thought to be caused due to abnormalities of basal ganglia.
It usually starts with a mild dystonic posture which gradually becomes severe. It manifests as either fixed or intermittent jerky type or a combination of both.
It usually becomes worse during the first 5 years of onset and then eventually stops progressing.
It severely affects activities of daily living and a person’s self-confidence. Spontaneous remission is seen in 20% of patients, but that is usually not complete or prolonged. Also, nearly all patients relapse within 5 years.
2. Secondary Torticollis
This is not so common. It could be due to focal brain lesions of various origins, neurodegenerative disorders, metabolic disorders, drugs, and chemicals that affect the basal ganglia, thalamus, and brainstem and following peripheral injury.
Non-dystonic torticollis or Pseudodystonia
Associated with sustained muscle contractions, due to reflex mechanisms, or example, tilting of the head to improve vision in 4th (trochlear nerve) palsy or in hemianopia.
Non-dystonic torticollis can be divided into:
1. Congenital torticollis
presents at birth but comes to notice late because head control develops only at 3 months. It is caused due to in utero malposition (breech presentation), birth trauma, malformations of the cervical spine, hypertrophy of cervical muscles, Arnold Chiari malformations.
2. Acquired Torticollis
presents during infancy or early childhood. It is caused due to CNS tumors, syringomyelia, musculoskeletal abnormalities of the cervical spine like atlantoaxial dislocation, cervical spine osteomyelitis, benign paroxysmal torticollis. Psychogenic causes may occur during adolescence.