Online newspaper of professor Yasser Metwally

The author: Professor Yasser Metwally

http://yassermetwally.com

INTRODUCTION

July 30, 2008 — “Torticollis” is the common term for various conditions of head and neck dystonia, which display specific variations in head movements (phasic components) characterized by the direction of movement (horizontal, as if to say “no, no” or vertical, as if to say “yes, yes”). Such to and fro movements of the head can be equal (as in a tremor) or unequal (ie, rapid clonic movements of the head and neck with slow recovery, termed “spasmodic”).

Characteristic head tilt often occurs from a tonic component. One example is laterocollis, in which the head is displaced with the ear moved toward the shoulder from increased tone in the ipsilateral cervical muscles. Another is rotational torticollis, in which partial rotation or torsion of the head occurs along the longitudinal axis. This should not be confused with idiopathic torsion dystonia, which is the overall category of generalized dystonia (originally envisioned to have athetotic components even though these are quite rare). In anterocollis the head and neck are held in forward flexion with increased tone of anterior cervical muscles, whereas in retrocollis the head and neck are held in hyperextension with increased tone in the posterior cervical muscles.

No matter which term is preferred in communicating about these conditions, the implication is that they all represent differing degrees of the same phenomenon. Jankovic et al, [3] and Chan et al, [4] would like to avoid the popular term “spasmodic torticollis” and prefer “cervical dystonia,” since many patients have neither simple rotation nor spasmodic movements. In fact, several patients have combinations of movements, not as simple tremors but as responses to dystonic motor control.

• Pathophysiology

As a neurodegenerative disease, torticollis or idiopathic cervical dystonia is believed to arise from basal ganglia circuit abnormalities stemming from selective vulnerability of these structures to an abnormal biochemical process that leads to neuronal loss. Some indication of involvement of dopamine-secreting circuits comes from findings of low levels of metabolites of dopamine in the cerebrospinal fluid and some minor improvements reported from individual trials of levodopa and traditional neuroleptics, both of which possess equal D1 and D2 receptor-binding properties. Neither moderate-dose levodopa nor high-dose anticholinergics are as effective as in idiopathic torsion dystonias or inherited dystonias, which therefore have clearly different receptor responses and circuit abnormalities.

The use of selective D2 ligands with single-photon emission computerized tomography (SPECT) scanning in 10 patients with torticollis has shown reduced D2-receptor binding in the basal ganglia [6]. Similar results have been noted in focal hand dystonia using SPECT [5] and positron emission tomography (PET) scanning [7]. The implication is that underactivity occurs in the D2 dopamine receptors located in the indirect pallidal outflow pathway in both conditions. Such underactivity can be expected to cause disinhibited thalamocortical output and dystonic postures.

This relative imbalance between direct (D1-related) and indirect (D2-related) pallidal outflow pathways explains the failure of levodopa to improve torticollis adequately and the transient improvement from traditional neuroleptics, which initially may reduce D1 activity and eventually both D1 and D2 activity in both pathways.

The authors have tried pramipexole, a dopamine agonist with selective, highly potent binding properties to D2 and D3 receptors, in an open label trial with 14 patients with idiopathic cervical dystonia who displayed uncomplicated torticollis (unpublished results). Reduction in stiffness of neck muscles and head movements was reported in 6 patients who received 1.5 mg 3 times per day for at least 2 years. Five of 8 patients improved on 5 mg olanzapine, a dopamine-receptor blocker with minimal D1-blocking potency compared to its major D2- and D3-blocking potency. Atypical neuroleptic action suggests a bilateral relative binding effect, in which blocking the D2 action on the opposite indirect pathway may “enhance” the ipsilateral D2 receptor effect by comparison. This observation may suggest a mechanism of bilateral rather than unilateral basal ganglia control of torticollis.

Although the D3 activity of pramipexole has been linked to improvement in mood [8], D3 receptors also are found in the striatum of the basal ganglia and may provide a role complementary to the expected increased activity in the indirect pathway provided by D2 action of the drug. The action of the atypical neuroleptic olanzapine is quite interesting and needs far more extensive evaluation before a mechanism of rebalance can be offered.

Further studies of receptor binding will be helpful in clarifying the unknown process leading to the slow evolution and progression of torticollis. Such understanding is also necessary in providing viable medication alternatives to repeated botulinum toxin injections every few months and the surgical alternatives offered in cases of injection failure.

• Clinical picture

  • History

Of patients with torticollis (cervical dystonia), 80-90% fall into the idiopathic category, typically without family history. A positive family history suggests that the case in question may in fact be a residual form of an inherited generalized dystonia. The remaining 10-20% of patients with torticollis (cervical dystonia) fall into the posttraumatic category.

Other neurologic problems can mimic torticollis, and the practitioner should be alert to a history of adversive seizures, homonymous hemianopsia, and various ocular disturbances that lead to head tilt, including a variety of cervical spinal deformities, ocular palsies, congenital nystagmus, labyrinthine disease, and probable cervical adenitis.

• Idiopathic cervical dystonia demonstrates a slowly progressive course initiated in patients aged 30-50 years.

  • Details of the extent of dystonia (including dystonic speech, involvement of upper limbs, other body parts with painful sustained contractures) may suggest a genetic, more generalized form of dystonia but also can occur as a natural progression of cervical symptoms over time.

  • Jahanshahi et al, [1] reported progression of dystonic symptoms to extranuchal but still cervical innervated sites (hand, arm, oromandibular region) in 32% of 72 patients with adult-onset cervical dystonia.

  • In addition, Comella et al, [2] observed both clinical dysphagia and subclinical swallowing motility disturbances in such patients.

  • Action-induced or activity-induced worsening of torticollis and dystonia are typical, as are variable periods of lessened symptoms in the morning (ie, “morning benefit”). Patients often discover certain sensory tricks (ie, “gestes antagonistiques”) that reduce head and neck movement (eg, touching the face in a particular spot with the thumb). The presence or absence of sensory tricks can help distinguish acute traumatic torticollis and nondystonic torticollis from idiopathic and delayed dystonic torticollis.

  • A positive history of chronic neuroleptic drug use may call attention to possible tardive dystonia.

  • Of patients with cervical dystonia, 10-20% experience spontaneous self-limited remissions that may be quite brief or last as long as 2-3 years.

• Posttraumatic cervical dystonia is divided into 2 subtypes, acute onset (initiated immediately to a few days after head and neck trauma) and delayed onset (3-12 mo after head and neck trauma).

  • Characteristics of acute posttraumatic cervical dystonia include local pain immediately following trauma such as concussion or whiplash injury, followed within days by a marked limitation in range of motion of the neck and an abnormal posture of the head without phasic components, elevation of the shoulder, and eventual hypertrophy of the trapezius. Two characteristics distinguish acute posttraumatic from idiopathic and delayed posttraumatic cervical dystonia: (1) no increase in symptoms with effort and (2) no inhibitory response to sensory tricks.

  • Delayed-onset posttraumatic cervical dystonia is nearly identical to idiopathic cervical dystonia and includes activation by effort and the ability to minimize symptoms by the use of sensory tricks.

• Whether occupational overuse or subacute recurring trauma can lead to cervical dystonia, as hypothesized with focal hand dystonia (writer’s cramp) or musicians’ syndromes, is uncertain [9].

  • Physical

The primary goal in physical examination is to locate evidence for torticollis or cervical dystonia as the obvious primary finding representing the primary process, with additional dystonic features in the limb or hand being minimal and typically unilateral. Generalized dystonia does not reinforce the diagnosis but draws attention to idiopathic torsion dystonia or one of the genetic forms of dystonia.

1. Characterization of head and/or neck posture (tonic components) and of dystonic head movements (phasic components)

   • Tonic head and neck posture (when chronic, may cause scoliosis)

     • Rotational torticollis: Head is turned around the long axis with nose and chin toward the shoulder; this is the most common head and neck deviation. This is not synonymous with “torsion dystonia,” a generalized dystonia named for rare athetoid components. Tone and bulk increase are appropriate in the sternomastoid contralateral to the direction of turn.

     • Simple torticollis: No head tilt is present. Document increased tone of neck muscles as symmetric or absent, hypertrophied or normal.

     • Laterocollis: Head tilts to one side with ear toward shoulder; asymmetric tone and muscle bulk also present.

     • Anterocollis: Head tilts forward with chin toward the chest, and anterior cervical muscles are increased in tone and bulk.

     • Retrocollis: Head tilts in hyperextension with increased tone and bulk in the posterior cervical muscles.

   • Phasic head components

     • Spasmodic jerks – Rapid irregular clonic jerks with less rapid recovery toward the neutral position

     • High-frequency oscillations – Horizontal, vertical, mixed, or irregular tremors

2. Other dystonic features

   • Extranuchal dystonias may occur on the side ipsilateral to the cervical dystonia (if bilateral or contralateral, consider more generalized or torsion dystonias).

   • Oral, facial, or mandibular dystonias occasionally are associated with blepharospasm and laryngeal dystonia but not with neuroleptic use.

3. Nondystonic findings

   • Swallowing difficulty (trouble initiating)

   • Cervical radiculopathies (secondary to bony changes)

   • Ulnar neuropathy secondary to performing sensory tricks

   • Reactive depression, self-consciousness

References

1. Jahanshahi M, Marion MH, Marsden CD: Natural history of adult-onset idiopathic torticollis. Arch Neurol 1990 May; 47(5): 548-52
2. Comella CL, Tanner CM, DeFoor-Hill L, Smith C: Dysphagia after botulinum toxin injections for spasmodic torticollis: clinical and radiologic findings. Neurology 1992 Jul; 42(7): 1307-10
3. Jankovic J, Leder S, Warner D, Schwartz K: Cervical dystonia: clinical findings and associated movement disorders. Neurology 1991 Jul; 41(7): 1088-91
4. Chan J, Brin MF, Fahn S: Idiopathic cervical dystonia: clinical characteristics. Mov Disord 1991; 6(2): 119-26
5. Horstink CA, Booij J, Berger HJC: Striatal D2 receptor loss in writer’s cramp. Mov Disord 1996; 11: P784.

6. Naumann M, Pirker W, Reiners K, et al: Imaging the pre- and postsynaptic side of striatal dopaminergic synapses in idiopathic cervical dystonia: a SPECT study using [123I] epidepride and [123I] beta-CIT. Mov Disord 1998 Mar; 13(2): 319-23.

7. Perlmutter JS, Stambuk M, Markham J: Quantified binding of [F18]spiperone in focal dystonia. Mov Disord 1996; 11: P819.
8. Cummings JL: D-3 receptor agonists: combined action neurologic and neuropsychiatric agents. J Neurol Sci 1999 Feb 1; 163(1): 2-3
9. Jankovic J: Can peripheral trauma induce dystonia and other movement disorders? Yes! Mov Disord 2001 Jan; 16(1): 7-12