Multiple Sclerosis (MS)
A 35-year-old woman was active in jogging and horseback riding until 1 year ago. During the past year she began to notice severe weakness and paresthesias in her legs. Her gait became unsteady, and she developed loss of vision in one eye. A neurologist suspected multiple sclerosis (MS) and ordered the following studies:
Routine laboratory work Within normal limits (WNL)
Lumbar puncture with cerebrospinal fluid (CSF) examination, p. 651
Immunoglobulin (Ig) G index 0.8 (normal: 0.3-0.7)
IgG determination 20% (normal: 0%-11% of total protein)
Oligoclonal bands Present (normal: none)
Evoked potentials (EPs), p. 562
Visual-evoked potentials Abnormal latency
Auditory brainstem-evoked potentials Normal
Somatosensory-evoked responses Abnormal latency
Magnetic resonance imaging (MRI), p. 1106 Plaques indicative of multiple sclerosis
The wide variety of symptom manifestation often makes MS difficult to diagnose; however, the above studies clearly identified MS as the patient’s problem. The CSF study results were classic for the diagnosis of MS. The abnormal latency demonstrated on the EP studies was the result of the demyelination process of MS. MRI revealed plaques indicative of MS.
The patient was given prednisone to decrease the inflammation and associated edema of the myelin sheath. When remission occurred, she was instructed about factors that exacerbate, prevent, or ameliorate symptoms.
Critical Thinking Questions
1. Why were the results of the CSF study classic for the diagnosis of MS?
2. What is latency, and why is it increased in MS?