Camptocormia

Camptocormia is an abnormal forward flexion of the trunk of more than 45 degrees that appears on standing or walking and disappears on lying down. It is a sign with many causes rather than a single disease.

It is most often reported in Parkinson disease, where it affects a minority of patients, and in axial myopathies of older adults.

Pathophysiology. Mechanisms include truncal dystonia, paraspinal myopathy with fatty replacement, rigidity, impaired proprioception and a central disturbance of postural control. Causes include Parkinson disease, multiple system atrophy, isolated paraspinal myopathy, inflammatory myopathy, motor neuron disease, myasthenia gravis, dystonia, spinal surgery or stenosis, and drugs such as dopamine agonists and antipsychotics.

Progressive bending that worsens through the day and with walking, fatigue, low back pain, difficulty looking forwards, falls and sometimes dysphagia. Correction when supine or with passive support suggests camptocormia rather than fixed kyphosis from vertebral fracture or ankylosing spondylitis.

Red flags.

• Rapid progression or weight loss.
• Neck extensor weakness (dropped head) or bulbar signs, suggesting motor neuron disease or myasthenia.
• Sphincter disturbance or leg weakness with sensory level, suggesting cord compression.

Measure the angle of trunk flexion standing, seated and lying. Examine for parkinsonism, weakness, fasciculation and dystonia. Test creatine kinase, inflammatory markers, thyroid function and acetylcholine receptor antibodies. Perform MRI of the spine and paraspinal muscles and electromyography of paraspinal muscles, with muscle biopsy for suspected myopathy.

Differential diagnosis.

• Fixed kyphosis from osteoporotic fracture, spondylosis or ankylosing spondylitis.
• Lumbar spinal stenosis (flexion relieves pain).
• Dropped head syndrome and pain related stooping.

Treat the cause. Reduce or stop dopamine agonists or other culprit drugs and adjust levodopa. Give corticosteroids or immunotherapy for inflammatory myopathy. Offer physiotherapy for back extensor strengthening and postural training, with analgesia and a wheeled walker. Spinal bracing is poorly tolerated. Botulinum toxin and deep brain stimulation give inconsistent benefit, and spinal fusion carries high failure rates.

Monitoring. Trunk angle, pain and walking ability every 6 months.