Medicine>>>>>Hematology and Oncology
Question 15#

A 64-year-old woman who is receiving chemotherapy for metastatic breast cancer has been treating midthoracic pain with acetaminophen. Over the past few days she has become weak and unsteady on her feet. On the day of admission she develops urinary incontinence. Physical examination reveals fist percussion tenderness over T8 and moderate symmetric muscle weakness in the legs. Anal sphincter tone is reduced.

Which of the following diagnostic studies is most important to order? 

A. Serum calcium
B. Bone scan
C. Plain radiographs of the thoracic spine
D. MRI scan of the spine
E. Electromyogram with nerve conduction studies

Correct Answer is D

Comment:

Spinal cord compression is an oncologic emergency. Major neurological deficit is often irreversible and severely compromises the patient’s remaining quality of life. Vertebral and then epidural involvement precede the neurological findings; the thoracic cord is involved 70% of the time. The patient is often given high-dose dexamethasone before being sent for MRI. In the presence of neurological compromise, the definitive test, MRI scan, should be performed as quickly as possible. Multiple epidural metastases are noted in 25% of patients; their presence can affect treatment (eg, the extent of radiation therapy fields). If no neurological abnormalities are present, most experts recommend plain radiographs of the painful vertebra as the initial diagnostic test. A radionuclide bone scan would reveal the vertebral involvement but would not show the degree of spinal cord compromise. Electromyogram and nerve conduction studies would be normal in spinal cord disease. Bone scan and thoracic spine films are less specific than MRI. Hypercalcemia might cause confusion but not spinal cord signs.