Section 6. Brain, Spinal Cord, and Nerve Disorders

Chapter 93. Spinal Cord Disorders

Topics: Introduction | Accident-Related Injuries | Spinal Cord Compression | Cervical Spondylosis | Spinal Hematoma | Syrinx | Hereditary Spastic Paraparesis | Acute Transverse Myelitis | Blockage of the Blood Supply | Subacute Combined Degeneration of the Spinal Cord

Spinal Cord Compression

Normally the spinal cord is protected by the spine, but certain disorders may put pressure on the spinal cord, disrupting its normal function. The spinal cord may be compressed suddenly, producing symptoms in minutes or over a few hours or days, or slowly, producing symptoms that progress over many weeks or months.

Sudden compression usually results from an injury, which can cause a fracture or dislocation of a vertebra. Sudden compression may also result from bleeding, an infection, an abscess, or a ruptured or herniated disk in the spine (see Section 6, Chapter 94).

Slowly developing compression may be due to a tumor in the spinal cord or spine, an infection, a blood vessel (arteriovenous) malformation, or an abnormal bone growth. Spinal stenosis (narrowing of the spinal canal) can gradually compress the cord, causing back pain. An injury, cancer, or osteoporosis may cause vertebrae to collapse, compressing the spinal cord. Collapse of a vertebra is called a compression fracture (see Section 5, Chapter 62).

See the sidebar What Is the Cauda Equina Syndrome?

Symptoms

If compression of the spinal cord is minimal, only some nerve signals going up and down the spinal cord may be disrupted. Symptoms may include discomfort only in the back, minor weakness, tingling, other changes in sensation, or erectile dysfunction (impotence). If compression increases, symptoms may worsen. If compression is great, most nerve signals may be blocked, causing severe weakness, numbness, incontinence or retention of urine, and loss of bowel control. If all nerve signals are blocked, paralysis and complete loss of sensation result. A beltlike band of discomfort may be felt at the level of spinal cord compression. Once spinal cord compression begins to cause symptoms, the damage usually worsens from minimal to substantial unpredictably but rapidly in a few hours to a few days.

Diagnosis

Because the spinal cord is organized in a specific way, doctors can determine which part of the spinal cord is affected based on the symptoms and results of a physical examination. For example, if the legs (but not the arms) are weak and numb and bladder and bowel function are impaired, the midchest (thoracic) area of the spine may be damaged. The location of pain or tenderness along the spine also helps doctors determine the site of the damage.

Magnetic resonance imaging (MRI) or myelography with computed tomography (CT) usually shows where the spinal cord is compressed and may indicate the cause. MRI or myelography with CT can detect a fracture or dislocation of a vertebra, a ruptured or herniated disk, an abnormal bone growth, an area of bleeding, an abscess, or a tumor.

The cause of the compression can be identified when surgery is performed immediately to relieve the pressure on the spinal cord. If surgery is not needed immediately or cannot be performed, a biopsy with a needle is performed to identify the cause. Placement of the needle is guided by CT. Occasionally, a biopsy is performed to determine whether an abnormal growth or a tumor is cancerous.

Treatment

The compression must be relieved immediately to prevent permanent damage to the spinal cord. When the compression is detected and treated before nerve pathways are destroyed, function is usually completely recovered. Corticosteroids (such as methylprednisolone or dexamethasone) are given intravenously in high doses by injection to reduce swelling in or around the spinal cord. Swelling may be contributing to the compression. These drugs are given as soon as possible, but if the cause is an injury, they must usually be given within 8 hours to be effective. If surgery cannot be performed, radiation therapy may relieve compression caused by tumors. Surgery is needed to remove blood, bone fragments, a tumor, a herniated disk, or an abnormal bone growth. Other measures may be needed to stabilize the spine.

Spinal cord compression caused by an abscess must be treated immediately. A doctor, usually a neurosurgeon, drains the abscess, sometimes by drawing out the pus through a syringe. Alternatively, the abscess can be surgically removed. Antibiotics are also given.