Dystonia

INDEX

                                                                                                   Anterocollis                              Retrocollis                              Pisa Syndrome

Axial dystonia and scoliosis and kyphoscoliosis are frequent concomitant manifestations of PD:  Postural deformities in PD may be secondary to central mechanisms like dystonia, rigidity and proprioceptive disintegration while peripheral causes such as myopathy and skeletal and soft tissue changes may also play a role.

Camptocormia refers to extreme flexion of the trunk which follows the pattern of the stooped posture typically seen in PD, but which is much more severe. An arbitrary definition is that there is at least 45° thoracolumbar flexion apparent when standing or walking, but which resolves or improves when lying down. Patients with camptocormia tend to be older, and to have more advanced parkinsonism, with the condition typically presenting 7-8 years after diagnosis. Abdominal, hip and spine surgery have been described as the triggering events for camptocormia.

The condition is naturally variable in severity, being most obvious when walking or leaning against a wall.  Some patients are able to correct their posture on request, whereas in others the condition is fixed until they lie flat. Examination may reveal marked axial rigidity, with the paraspinals and rectus abdominis muscles feeling contracted to palpation. Some patients report a feeling of being pulled forward, or a sensation of tightening in their abdomen.
Synonyms
Bent spine syndrome is a synonym for camptocormia.
Dropped head syndrome is typically attributed to neuromuscular disease.

Pathophyiology
Response to sensory tricks, alleviation with botulinum toxin and improvement following pallidotomy/DBS suggest dystonia as a possible explanation in at least a proportion of cases. The condition is not usually levodopa responsive. It is possible, although unproven, that the manoeuvre of standing against a wall to enable erect posture represents a geste antagoniste or sensory trick1.

Special Investigations
EMG studies have shown excessive activation of abdominal muscles.

Treatment
Botulinum toxin injection to the rectus abdominis, iliopsoas, or selected paraspinal muscle groups.
DBS (bilateral STN): response is variable, and this procedure should likely only be undertaken with caution.
Spinal surgery and spinal orthotic devices

Figure 1. Camptocormia in the standing, seated, and supine positions

From: Doherty KM, van de Warrenburg BP, Peralta MC, Silveira-Moriyama L, Azulay JP, Gershanik OS, Bloem BR. Postural deformities in Parkinson's disease. Lancet Neurol. 2011 Jun;10(6):538-49. 
 


 

Video 1. Patient with a reversible form of camptocormia

 


(vv)Gait1.mp4(tt)

 

Video 2. Patient with a fixed form of camptocormia

 

(vv)Gait2.mp4(tt)

From: Doherty KM, van de Warrenburg BP, Peralta MC, Silveira-Moriyama L, Azulay JP, Gershanik OS, Bloem BR. Postural deformities in Parkinson's disease. Lancet Neurol. 2011 Jun;10(6):538-49. 


 

Anterocollis
This refers to a forward flexion of the head and neck. When mild it may be viewed as a part of the stooped posture of PD; severe anterocollis is usually associated with disproportionate flexion of the head and neck in comparison to the posture of the limbs and trunk. It is more commonly seen in long-standing cases of PD, where it is often combined with pronounced head tilt and possibly some rotation2.

Anterocollis does not improve with sensory tricks. The condition may be commoner in women, and is associated with parkinsonism with prominent rigidity and akinesia.  Anterocollis in PD is often associated with substantially increased axial tone, although patients might still be capable of passive extension to the normal position. In other patients, the antecollis can become a fixed deformity, even shortly after onset. Anterocollis may also occur largely in the off state, and is also occasionally reported to have been triggered by dopamine agonists and amantadine, sometimes irreversibly.

There may be associated difficulty swallowing, excessive drooling, or restricted vision.

Anterocollis is more common in multiple system atrophy (MSA) with a prevalence of 40% while a much lower prevalence is reported in PD (5%).  Typically, anterocollis in MSA is relatively fixed, as compared to idiopathic spasmodic torticollis/cervical dystonia.  A substantial limitation of neck movement appearing subacutely likely makes it necessary to image the cervical spine.Anterocollis has also been reported secondary to levodopa and amantadine, as an “off” phenomenon, or secondary to dyskinesia due to dopaminergic therapy associated with fluctuations.

In the early stages, hypertrophy and spasms might be visible in various anterior and posterior neck muscles, whereas contraction of the posterior neck muscles, particularly of the splenius capitis and trapezius, becomes prominent later. Most studies report normal strength upon testing of neck extension. In anterocollis, muscles that originate at the transverse processes of the cervical vertebrae (scalenus scapulae and longus colli muscles) are likely to be affected on both sides, though they cannot easily be assessed without EMG. 

Muscles involved may include:
Splenius capitis
Trapezius
Sternocleidomastoid
Prevertebral deep neck flexors (longus colli, scalene muscles)

Differential Diagnosis
Dropped head syndrome refers to a condition of marked neck flexion, mainly seen in motor neuron disease, myopathies, and myasthenia gravis, and related to weakness of neck extensors. In anterocollis, muscle strength should be normal.

Treatment
Muscle relaxants/intensive physiotherapy
Botulinum toxin
DBS

Retrocollis
This refers to an abnormal head posture, with the head held in extension.

This is associated with axial rigidity and with progressive supranuclear palsy (PSP), and is a classical presentation of tardive dystonia, as well as being a manifestation of primary cervical dystonia.
Retrocollis is an unusual feature of PD.

Pisa syndrome
This condition is characterized by marked lateral flexion of the trunk, which resolves on lying down. It was previously described as an adverse effect of dopamine blocking agents but it is now known to also be associated with PD.
Definition is lacking, but standard features are:

Pisa syndrome may precede scoliosis in PD, and is distinct entity different from scoliosis. The term scoliosis should be reserved for patients whose posture cannot be improved by passive movement or supine positioning, and who have radiological evidence of a structural curve with axial vertebral rotation that persists when the effect of gravity has been eliminated (ie, on a supine image).

Treatment
Pisa syndrome may have a variable response to botulinum toxin and DBS surgery. Occasionally patients respond to the combination of DBS surgery and levodopa. There are rare reports of development of Pisa syndrome following pallidotomy (88,89). Complex corrective spinal surgery can successfully improve the camptocormic posture but is associated with a very high complication rate.
 


 

Video 3. Patient with Pisa syndrome

 

(vv)Gait3.mp4(tt)
From: Doherty KM, van de Warrenburg BP, Peralta MC, Silveira-Moriyama L, Azulay JP, Gershanik OS, Bloem BR. Postural deformities in Parkinson's disease. Lancet Neurol. 2011 Jun;10(6):538-49. 
 


 

 

 

References

 

1.           Doherty KM, van de Warrenburg BP, Peralta MC, et al. Postural deformities in Parkinson’s disease. Lancet Neurol [Internet] 2011;10(6):538–49. Available from: http://dx.doi.org/10.1016/S1474-4422(11)70067-9

2.           Shetty AS, Bhatia KP, Lang AE. Dystonia and Parkinson’s disease: What is the relationship? Neurobiol Dis [Internet] 2019;132. Available from: https://doi.org/10.1016/j.nbd.2019.05.001

References