ESSENTIALS OF DIAGNOSIS
Complication of metastatic solid tumor, lymphoma, or plasma cell myeloma.
Back pain is most common presenting symptom.
Prompt diagnosis is essential because once a severe neurologic deficit develops, it is often irreversible.
Emergent treatment may prevent or potentially reverse paresis and urinary and bowel incontinence.
Cancers that cause spinal cord compression most commonly metastasize to the vertebral bodies, resulting in physical damage to the spinal cord from edema, hemorrhage, and pressure-induced ischemia to its vasculature. Persistent compression can result in irreversible changes to the myelin sheaths resulting in permanent neurologic impairment.
Prompt diagnosis and therapeutic intervention are essential, since the probability of reversing neurologic symptoms largely depends on the duration of symptoms. Patients who are treated promptly after symptoms appear may have partial or complete return of function and, depending on tumor sensitivity to specific treatment, may respond favorably to subsequent anticancer therapy.
Back pain at the level of the tumor mass occurs in over 80% of cases and may be aggravated by lying down, weight bearing, sneezing, or coughing; it usually precedes the development of neurologic symptoms or signs. Since involvement is usually epidural, a mixture of nerve root and spinal cord symptoms often develops. Progressive weakness and sensory changes commonly occur. Bowel and bladder symptoms progressing to incontinence are late findings.
The initial findings of impending cord compression may be quite subtle, and there should be a high index of suspicion when back pain or weakness of the lower extremities develops in a cancer patient.
MRI is usually the initial imaging procedure of choice in a cancer patient with new-onset back pain. If the back pain symptom is nonspecific, a whole-body PET scan with 18F-2-deoxyglucose may be a useful screening procedure. Bone radiographs are neither sensitive nor specific for the evaluation of a cancer patient with back pain. When neurologic findings suggest spinal cord compression, an emergent MRI should be obtained; the MRI should survey the entire spine to define all areas of tumor involvement for treatment planning purposes. MRI has a sensitivity of 93% and a specificity of 97% for diagnosis of metastatic spinal cord compression.
Patients with a known cancer diagnosis found to have epidural impingement of the spinal cord should be given corticosteroids immediately. The initial dexamethasone dose is 10–100 mg intravenously followed by 4–6 mg every 6 hours intravenously or orally. Patients without a known diagnosis of cancer should have emergent surgery to relieve the impingement and obtain a pathologic specimen; preoperative corticosteroids should not be given since they might induce a tumor response and compromise the pathology results. Patients with solid tumors who have a single area of compression and who are ...