Section 8: Neurological Disorders
When evaluating a spinal cord lesion near a bone, the best imaging choice would be which of the following?
A. Computed tomography (CT)
B. Computed tomography angiography (CTA)
C. Magnetic resonance imaging (MRI)
D. Single-photon emission computed tomography (SPECT)
The answer is C. MRI is better than CT for examining lesions near bone because the x-rays used in CT are scattered by the bony structures and produce artifact on the image. MRA is for examining the circulatory system. SPECT is a test of brain function. See section “Diagnosing Neurologic Anatomic Abnormalities” for a full discussion.
Lumbar puncture is most useful in the diagnosis of which of the following?
The answer is C. Lumbar puncture samples the CSF and is useful for diagnosing an infection such as meningitis in this space. See section “Laboratory Findings for Neurological Disorders and Their Interpretation” and Table e70-3 for more discussion of lumbar puncture findings.
Which of the following is a component of the neurologic examination?
The answer is B. The neurologic examination consists of the following domains: higher cortical function (mental status), cranial nerves, motor function, reflexes, cerebellar function, sensory function, and gait. See section “The Neurologic Examination” for a discussion of the examination and Table e70-2 for common findings.
You are presented with the following cerebrospinal fluid (CSF) results: red blood cells = 400/mm3 (400 × 106/L), white blood cells = 0/mm3 (0 × 106/L), protein = 200 mg/dL (2.0 g/L), and xanthochromia. Which of the following is the best interpretation?
D. Subarachnoid hemorrhage
The answer is D. A comparison of these CSF results to Table e70-3 demonstrates values consistent with subarachnoid hemorrhage. Red blood cells are elevated, protein is elevated, and the sample is xanthochromic.