Neurology -- Correspondence for Azher and Jankovic, 65 (3) 355-359

Correspondence published:

Reply to McCluskey: Joseph Jankovic, MD, Shaheda Azher, MD, Baylor College of Medicine (20 September 2005)

Camptocormia: Pathogenesis, classification, and response to therapy: Leo F. McCluskey (20 September 2005)

Reply to McCluskey 20 September 2005

Joseph Jankovic, MD,
Baylor College of Medicine
The Smith Tower, Suite 1801 Houston,TX.77030,
Shaheda Azher, MD, Baylor College of Medicine
Send Correspondence to journal:
Re: Reply to McCluskey

josephj{at}bcm.tmc.edu Joseph Jankovic, MD, et al.

We appreciate Dr. McCluskey?s interest in our review article and his comments. Although he provides no information on his cases, he argues that extensive neurophysiological and neuroimaging evaluations may uncover neuromuscular etiologies for camptocormia.
As stated in the first paragraph of the Discussion portion of our article [1], our series was based on a population of patients evaluated in a movement disorders clinic, hence the preponderance of movement disorders. Although a few reports suggest that extensor thoracic myopathies may be responsible for some cases of camptocormia, the interpretation of the muscle biopsies and EMG in those cases has been controversial and many experts have attributed those changes to chronic contractions of the antigravity muscles involved in compensatory trunk extension rather than to primary myopathies. [2]
In a study of 27 patients with camptocormia, EMG of the paravertebral muscles was difficult since the patients were unable to extend their trunks, and the recordings were uninterpretable in 16 cases. Other studies showed non-specific changes in muscle biopsies without any evidence of myopathy. [3] Likewise, imaging studies often reveal changes that are likely to be secondary to rather than the primary cause of camptocormia.
Even though imaging studies were not done in all our patients, in those who had X-rays or MRIs of the spine, we could not find any radiological features that differentiated patients with PD and camptocormia from those without camptocormia. We believe that our discussion adequately addresses these concerns, although because of space limitations we were not able to review all the relevant studies in detail.
Finally, the primary aim of our article was to draw attention to the heterogeneous etiologies of camptocormia, summarized in table E-1 on the Neurology web site [www.neurology.org].
References
2. Laroche M, Delisle MB, Aziza R, et al. Is camptocormia a primary muscular disease? Spine 1995;20:1011-1016.
3. Djaldetti R, Mosberg-Galili R, Sroka H, et al. Camptocormia (bent spine) in patients with Parkinson's disease--characterization and possible pathogenesis of an unusual phenomenon. Mov Disord 1999;14:443-447.
The authors report no conflicts of interest.

Camptocormia: Pathogenesis, classification, and response to therapy 20 September 2005

Leo F. McCluskey,
University of Pennsylvania
330 South 9th Street , Philadelphia, PA 19107
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Re: Camptocormia: Pathogenesis, classification, and response to therapy

lfmcclusky{at}pahosp.com Leo F. McCluskey

Azher et al concluded that of 16 patients diagnosed with camptocormia, 11 developed it in association with Parkinson's disease (PD). Four had dystonia and one had Tourette's syndrome. [1] However, they did not report or perhaps did not perform electrodiagnostic testing and more specifically needle electromyography (EMG) examination of the thoracic paraspinal muscles in the individuals with isolated camptocormia and cervical paraspinal muscles in those who also manifested head drop.
The authors noted that no specific neuroimaging abnormalities were seen except for a thoracic syrinx in one patient. They did not report or did not perform thoracic or cervical spine MRI or CT imaging in each of the 16 patients and did not specifically remark about the signal characteristics of the extensor muscles in any case. These are significant limitations of their study.
The authors do reference in their discussion previous studies demonstrating that thoracic extensor myopathy can cause camptocormia and one study of four patients with PD and camptocormia caused by this disorder. This mirrors our experience in patients with camptocormia including those with PD and other movement disorders. A thorough evaluation that includes nerve conduction study, repetitive stimulation, EMG of limbs and involved extensor muscles, MR imaging of the spine with attention not only to bony and neural elements but also the signal characteristics of the paravertebral muscles, and possibly muscle biopsy of limb or paravertebral muscle often uncovers a neuromuscular cause.
With isolated head drop, the most common neuromuscular causes we have encountered are isolated cervical extensor myopathy, inclusion body myopathy, MG and ALS. For those with isolated camptocormia, the most common neuromuscular causes we have encountered are isolated thoracic extensor myopathy and ALS. For those with both the most common causes we have encountered are isolated extensor myopathy (cervical and thoracic) and ALS.
It is implicit that patients with PD or other movement disorders who develop camptocormia, head drop, or both as a result of a neuromuscular disorder will not respond to Sinemet or dopamine agonists nor will they respond to botulinum toxin of anterior neck or abdominal musculature. Camptocormia should not be assumed to be caused by a movement disorder until neuromusuclar causes are excluded.
Reference
1. Azher SN, Jankovic J. Camptocormia: Pathogenesis, classification, and response to therapy. Neurology 2005;65:355-359.
The author reports no conflicts of interest.