DEFINITION OF SYRINGOMYELIA
SYRINGOMYELIA is a chronic progressive disease of the spinal cord associated with cavitation in the gray matter and white mater adjacent to central canal of spinal cord characterised by neurological deficits due to involvement of spinothalamic tract, corticospinal tracts and anterior horn cells.
Exact cause of this disease is the abnormal closure of the central canal of the spinal cord or inclusion of spongioblasts during the process of closure. From incomplete closure, cavities are formed surrounding which secondary gliosis develops or the spongioblasts from glial tissue may undergo cavitation. The word “syrinx” means cavity. In many cases Arnol chiari malformation may be associated. Cord cavitation may also be seen in intramedullary tumour or cord injury but in these cases the cavity does not communicate with central canal
CLINICAL FEATURES OF SYRINGOMYELIA
Onset is insidious.
Age: Usually 25-40 years.
Sex: Males are commonly affected.
Loss of pain and temperature sensation is first localised on one side. There may be dissociated sensory loss. Touch sensation usually persists but pain and thermal sensations are lost. The sensory loss is seen in shawl or “cape” like distribution and is also called “sleeve jacket” anaesthesia.
Weakness and wasting of small muscles of the hand may be present. Fasciculation may appear. Weakness and spasticity of the limbs with increased jerks, clonus and extensor plantar reflex may develop in the lower limbs while evidences of lower motor neurone lesion are seen in the upper limbs. Sphincteric reflexes are not much altered.
These are conspicuous. There may be proliferation and hypertrophy of the subcutaneous tissue or muscles in one-half of the body. Sweating is less but sometimes profuse. Painless arthropathies called Charcot’s joints may be seen in the shoulder, elbow and in spinal joints. Bones may be brittle and necrosis may develop. Cyanosis, ulcers, whitlows and gangrene may also be seen.
These include spina bifida, cervical rib, kyphoscoliosis, pes cavus, deformities of sternum and various others.
The lesion in the spinal cord may extend upwards in the medulla, giving rise to this condition. This is associated with Horner’s syndrome, paralysis of face, palate, larynx, pharynx and the tongue. Fasciculation of tongue is also present. Nystagmus may develop. There may be vertigo and trigeminal pain. Features of Bulbar palsy may develop.
Myelography may show a characteristic deformity of contrast media; but sometimes this may aggravate the features. CT scan and MRI scans are better.
1. Physiotherapy may be of help
2. Protection of anaesthetic areas from noxious stimuli should be done.
3. For intractable pain-analgesics and surgery (tractotomy and thalamotomy)
4. Surgical drainage of the spinal cavities or laminectomy may be done. Upper cervical cord and lower part of medulla may be decompressed surgically at foramen magnum. Syringo subarachnoid shunt can also be performed.
5. Deep X-ray therapy may be of some help particularly in cases of cord tumour after surgical removal. Surgery is also helpful in cases of cavitation after cord injury.