Parkinson's Disease with Camptocormia: A Central or Peripheral Etiology?
Abstract & Commentary
By Claire Henchcliffe , MD, Assistant Professor, Department of Neurology, Weill Medical College, Cornell University. Dr. Henchcliffe is on the speaker's bureau for GlaxoSmithKline, Teva / Eisai, and Boehringer Ingelheim.
Synopsis: Camptocormia in PD is an extreme forward flexion of the spine, and has many characteristics of an axial action dystonia. The contribution of myopathy in muscles responsible for trunk extension has yet to be determined, and may be secondary to the dystonia itself.
Sources: Bloch F et al. Parkinson's disease with camptocormia. J Neurol Neurosurg Psychiatry. 2006;77:1223; Lepoutre A-C et al. A specific pattern of camptocormia in Parkinson's disease. J Neurol Neurosurg Psychiatry. 2006;77:1229
In the first of two complementary studies, Bloch and colleagues identified 35 individuals with Parkinson's disease (PD) and camptocormia (defined as thoracolumbar anteroflexion 15°–90° standing or walking, disappearing when recumbent). Of these, 17 were studied in detail (exclusion criteria were known myopathy, dystonic syndrome, spinal cord disease, amyotrophic lateral sclerosis, spinal surgery, probable multiple system atrophy, and dementia). Mean age was 69.3 ± 7.2 years, 6/17 were women, mean disease duration was 12.2 ± 6.9 years, mean "off" Hoehn & Yahr score was 3.3 ± 0.9, and mean levodopa equivalent was 985 ± 535 mg/day. Spinal curvature responded poorly to levodopa (20%). Eight patients with PD but without camptocormia were compared, matched for age, disease duration, and Hoehn & Yahr score. Motor disability, as measured by the Unified Parkinson's Disease Rating Scale Part III, was worse "on" medication in subjects with camptocormia (24.7 ± 11.5 vs 13.3 ± 6.1, P < 0.05) but similar "off" medication. Similarly, axial motor scores were worse "on" medication for those with camptocormia (8.1 ± 2.6 vs 3.7 ± 1.5, P < 0.05), with more severe dysarthria, neck rigidity, gait, and postural instability. Interestingly, electro-oculographic recordings demonstrated abnormal horizontal gaze velocities in 28% of those with camptocormia, but in none of those without camptocormia. Electromyography failed to reveal evidence of myopathy in any. In the accompanying article, Lepoutre and colleagues examined 23 PD patients with camptocormia (defined as a totally or partially reducible forward flexion). Of the 23, 8 were women, mean age was 68.6 ± 7.4 years, mean disease duration was 10.3 ± 5.1 years, and onset was tremor-predominant in 12 vs akinetic-rigid in 13. MRI revealed abnormal signal in the thoracolumbar paraspinal muscles in 5/23 (non-specific in 2, and abnormally high signal on T2-weighted, fat-suppressed STIR sequence in 3). Myopathic changes were observed by electromyography in 3. Biopsy demonstrated focal paravertebral myositis (n = 1), type II fiber atrophy (n = 1), and fibrosis with fatty infiltration (n = 1).
Camptocormia, or "bent spine syndrome" is a poorly understood but debilitating and sometimes painful axial feature of PD.1 It also occurs in a variety of other disorders, including dystonia and ALS. Reports of camptocormia due to focal lesions of the striatum and pallidum suggest a central etiology, but it has also been associated with myositis, prompting a debate regarding relative importance of central vs peripheral (ie, muscle) etiologies. Although the present studies do not provide a definitive answer to this debate, they do suggest how the two processes might interrelate in development of camptocormia. The authors found that the presence of camptocormia in PD is associated with older age, male gender, longer disease duration, abnormal electro-oculographic studies in some, and autonomic features; therefore, it may represent a distinct clinical subtype. Its poor response to dopaminergic agents in general (in common with other axial features) is suggestive of neurodegeneration in non-dopaminergic pathways, either within the basal ganglia or other sites such as the brainstem. In fact, Lepoutre and colleagues suggest that organizational changes in the corticospinal and reticulospinal tracts might be responsible for axial rigidity, leading to underactivity of truncal extension muscles, and, thus, secondarily to muscle atrophy. The present rigorously conducted studies represent a focused attempt to discern what characteristics might be associated with camptocormia, and one suspects that in the final analysis it may turn out that multiple underlying mechanisms are responsible.
1. Azher SN and Jankovic J Camptocormia: Pathogenesis, classification, and response to therapy. Neurology. 2005;65:355-359