July '98
by Gary E. Frank, B.A., B.Ed., R.N.
Palliative Care Nurse Consultant, Edmonton Regional Palliative Care Program
Incidence and Course

Spinal cord compression (SCC) occurs in five to ten per cent of cancer cases. Patients with lung, breast, or prostate primaries are at the highest risk for this complication. As well, renal cell carcinomas, multiple myelomas, and lymphomas lead to SCC at significant rates. It is important, however, to be aware that SCC can occur with virtually any type of primary.

SCC requires immediate response both to maintain or achieve good pain control, and to prevent, reverse, or limit potentially permanent neurological damage. For these reasons it should be considered not only an oncological emergency but also a palliative care emergency. The most important determinant of neurological outcome is the degree of neurological impairment at the start of therapy. Delay in treatment may result in paralysis and lack of bowel and bladder control. About 80% of ambulatory patients will remain so if treatment is prompt. Some sources estimate that 30% of non-ambulatory patients will regain the ability to walk after treatment. However, in cases where SCC has already caused true paraplegia the chances of regaining the ability to ambulate are much less (0 to 10%). These statistics highlight the need for early assessment (including a good neurological physical exam) and intervention.

Malignant compression of the spinal cord is usually extrinsic in origin: pressure arises from the epidural space as a result of the extension of adjacent bony or soft tissue lesions. The majority of SCC's occur in the thoracic spine and are caused by extradural tumour extending posteriorly from an involved vertebrae. The epidural space can also be invaded through the intervertebral foramina by paraspinal lesions. This is more likely to occur in cases of lymphoma or neuroblastoma. Less frequently, intradural and intramedullary metastases can cause SCC.

Assessment
Early detection is extremely important. Signs and symptoms usually present several weeks prior to the onset of neurological crisis. Pain is almost always the first symptom. Yet often the diagnosis is not made until leg weakness or sensory deficits occur --possibly weeks after the onset of new pain. Warning signs to watch for are:

• central back pain, aggravated by movement, coughing, or straining.
• a sudden change in the nature of a long-standing pain.
• crescendo pain: pain with an intensity that waxes and wanes.
• pain aggravated by lying down or by leg raising.
• leg pain, either unilateral or bilateral, radiating from the back.
• Lhermitte's sign: a tingling, electrical sensation in the arms or trunk occurring when the neck is flexed.
• loss of bowel and bladder control.
• weakness and sensory deficits, usually of the lower extremities, starting in the feet and moving proximally.
• abnormal reflexes: asymmetrical, hypoactive, or hyperactive deep tendon reflexes; upgoing plantar reflexes.
  

Radiological Investigations
Plain x-rays of the spine can be normal with SCC. Therefore, radiological investigations should preferrably include magnetic resonance imaging (MRI) or, if MRI is not accessible, computed tomography (CT).

Interventions

1. Have the patient assessed by a physician immediately.
2. Stat administration of high dose steroids has been shown to significantly decrease both the incidence and the severity of permanent neurological damage associated with SCC. Be prepared to administer dexamethasone as soon as the diagnosis is made or strongly suspected. Commonly, 8 to 10 mg. po/sc tid or qid is prescribed, though higher or lower doseage regimes may be appropriate in certain cases. Usually, the dexamethasone doseage is tapered down once radiation therapy is started (see below).
3. Be prepared to assist in arranging referral of the patient, as soon as possible, to a centre where the diagnosis can be confirmed and therapy initiated (radiation therapy, or sometimes surgery).

References

• Caracini, A, Martini, C. "Neurological Problems". In: Doyle, D, Hanks, G, MacDonald N, ed. Oxford Textbook of Palliative Medicine, 2nd Edition, Oxford University Press, 1998.
• Pearcey, R.G. "Palliative Radiotherapy". Oral Presentation, Edmonton, Alberta, June 5. 1998.
• Pereira, J, Bruera, E. The Edmonton Aid to Palliative Care, Edmonton: Regional Palliative Care Program, 1997.