Infodystonia

Cervical dystonia: what does the examination look for? Dr Marion tells you how the clinical examination is important to optimise the Botox treatment.

Cervical dystonia: what does the examination look for?

 Patients with cervical dystonia described at onset an intermittent feeling of pulling in the neck muscles; over the months, the head take an abnormal posture. Torticollis is defined by the head (the chin) turned to one side; laterocollis by the head tilt toward one shoulder; retrocollis by the head pulled backward in extension, chin up; antecollis by the  head  flexed downward, chin down to the chest. These abnormal postures are due to the involuntary movement of the neck on the trunk. There is also the possibility of abnormal movement of the head on the neck, the head going forward like a goose or going backward giving a double chin posture.

The diagnosis of cervical dystonia is made on the involuntary movement and the abnormal posture of the head, and often delays by many years from the onset of symptoms. They are other rare causes of abnormal posture of the head that a neurologist can exclude by a neurological examination and investigations.

 But like the BSP, every patient is different and need to be examined carefully to document precisely the abnormal dystonic posture to know which muscle is pulling too much! Then these muscles, which are responsible of the pulling, will be the one to inject with Botulinum toxin.  The difficulty comes from the action of the neck muscles which are often mixed (rotating the head on one side and tilting on the other side), resulting in mixed abnormal posture of the head (predominant rotation with a degree of tilt and extension).

It’s best to see the patient at his worst!

The patient is asked to walk, to stand up, to write or to lie down depending of the triggering factors. Usually the worst posture is achieved standing, eyes closed. The fixation of the eyes on an object helps the person to keep the head straight; when closing the eyes, the head lost the visual cue and shift to its maximal abnormal posture. Then to write down the degrees of the rotation, tilt, extension and flexion to be able at the next visit to assess the improvement under treatment.

It’s also important to see the patient at his best!

I ask the patient if he has a “geste antagoniste” (French expression also used by the Anglo-Saxons neurologists!); for instance stopping the pulling in rotation by touching with one finger the cheek without exerting an opposing force to the movement. What’s count is the improvement of the pulling by simply touching a part of the head or neck. It’s also called sensory trick and it’s a hallmark of the dystonic phenomenon.

Then when the posture is clearly documented, identifying which are the leading muscles behind, is based on surface anatomy (palpation) and functional anatomy (which muscle is doing what!).