Spinal cord syndromes

The parts of the spinal cord affected

The clinical picture will vary depending on which spinal tracts are affected. These tracts cross at different levels which determines which side is symptomatic. There are four main tracts involved (Fig. 1):

Fig. 1 Cross-section of the spinal cord. Note the sensory input (red) from, and motor output (black) to, the right side.

Patterns of spinal cord lesion

There are five main patterns of spinal cord lesion:

Trauma

This is a common cause of spinal cord disease, especially in young men. Stabilizing the spine is important and the patient should be moved carefully. Other parts may also be injured, for example brain, chest, abdomen or limbs.

Neoplasms

These are usually extrinsic malignant metastases to the vertebrae and cause neurological compromise by expansion into the vertebral canal or by vertebral collapse (Fig. 2a). Common primary malignancies are bronchus, breast, myeloma, lymphoma and prostate. Primary extrinsic tumours are usually benign neurofibromas or meningiomas (Fig. 2b). Malignant lesions are painful and present acutely or subacutely. Benign lesions are usually painless and may develop very slowly.

Fig. 2 Spinal cord compression. (a) Multiple vertebral metastases (arrows) causing spinal cord compression; (b) cervical spinal cord compression caused by a large meningioma (arrow).

Intrinsic (intramedullary) tumours are rare and are usually astrocytomas or ependymomas. They usually present gradually, sometimes over many years, and are often painless.

Inflammatory spinal cord disease

This is most commonly due to multiple sclerosis (p. 84) but may represent an isolated episode, sometimes after infection. Other causes include sarcoidosis or collagen vascular diseases, for example Sjögren’s syndrome or systemic lupus erythematosus. They typically cause a neurological deficit evolving over a few days, but some slower syndromes occur.

Infection

This is a rare but important cause of acute, subacute or chronic syndromes. Paraspinal or epidural abscesses are painful and may present acutely (pyogenic) or more insidiously (tuberculous) with associated systemic symptoms (fever, sweats and weight loss). Brucellosis is an important cause of a subacute syndrome in parts of the world where unpasteurized milk is consumed. Myelopathy can develop chronically in infection with syphilis or HIV (p. 100). It is also seen in patients from the tropics with human T-cell lymphotropic virus I (HTLV-I) infection: ‘tropical spastic paraparesis’.

Vascular

Infarction produces a sudden onset of symptoms that are usually painless. Anterior spinal cord syndrome with a level at T8–T11 is the most common (relating to the artery of Adamkiewicz), but other patterns of spinal disturbance can occur. Vascular malformations of the spinal cord, for example dural arteriovenous fistulae, may produce a progressive deficit resembling a tumour. A characteristic feature is exacerbation of symptoms by exercise, which causes ‘claudication’ of the cord.

Degenerative cervical disc disease

This is the most common cause of spinal cord compression, especially in the neck (Fig. 3); its frequency increases with age. Cord compression can be due to:

degeneration of interverterbral discs with extrusion of disc material into the spinal canal – acute disc

formation of osteophytes, which impinge upon the spinal canal

forward or backwards slip of vertebrae, introducing kinks into the vertebral canal and thickening

calcification and protrusion of the ligamentum flavum and dentate ligaments.

Fig. 3 A T2-weighted sagittal MRI scan of the cervical spine showing a C5/6 disc compressing the spinal cord. There is associated signal change within the cord.

Pain is variable and the rate of progression may be acute or chronic. There is often associated root disease (p. 82).

Vitamin B12 and folate deficiencies

These present with a subacute myelopathy, especially affecting the dorsal columns. There may be a megaloblastic anaemia and other neurological changes such as mental slowing, cerebellar ataxia and peripheral neuropathy.

Genetic

A myelopathy is a component in a large number of rare inherited diseases, especially the ‘spinocerebellar degenerations’ such as Friedreich’s ataxia. This is an autosomal recessive condition due to a defect in frataxin. Ataxia begins between 8 and 15 years, with loss of reflexes (axonal neuropathy), optic atrophy and later cardiomyopathy; the patients are chair bound by their 40s. There is a slightly increased risk of diabetes. In familial spastic paraparesis, patients usually have severe spasticity of the legs with relative preservation of power and compensatory hypertrophy of the upper limb muscles.

Syringomyelia

This is a rare but classical disease. There is progressive expansion of a fluid cavity in the spinal cord, probably due to altered CSF dynamics. The cause may be a congenital abnormality such as a Chiari malformation (elongated cerebellar tonsils protrude through the foramen magnum, compressing the medulla at the craniocervical junction) or a tumour or trauma. The presentation is with a central cervical cord lesion (see above), which usually progresses slowly. The cavity may spread up to the medulla to give lower cranial nerve signs: ‘syringobulbia’.

Emergency treatment

In acute presentations, until spinal instability can be excluded, the patient should be moved with extreme caution, avoiding excessive flexion or extension of the neck, ideally with a hard collar. If an infective cause can be excluded, high doses of corticosteroids may protect the spinal cord from injury and temporarily reverse some of the deficit, especially in malignant compression. Spinal cord compression needs immediate neurosurgical referral and decompression.

Specific treatment

Specific treatment depends on the cause. Surgery is used in cases of extrinsic compression by a disc, spondylosis or benign tumour and selected cases of malignant tumour. Cervical spondylosis may be treated by posterior laminectomy, excision of disc material or anterior cervical decompression and fusion with grafts usually taken from the iliac crest. Osteophytes and ligamentous thickening may also require excision. Most patients with progressive neurological deterioration will require surgery.

Radiotherapy and chemotherapy and sometimes surgery are used for the treatment of malignant tumours. High-dose corticosteroids are used for non-infective inflammatory causes. Surgical decompression at the foramen magnum may help syringomyelia, if there is an associated Chiari malformation. Long-term rehabilitation is discussed on page 122.