62-Year-Old Man With Back Pain and Lower Extremity Weakness

A 62-year-old man presented to the emergency department with progressive lower back pain and bilateral lower extremity weakness and numbness. Laboratory studies including a complete blood cell count, electrolyte panel, measurement of hemoglobin A1c, thyrotropin, creatine kinase, aldolase, vitamin B12, thiamine, and monoclonal protein levels, tests for cyclic citrullinated peptide antibodies, antinuclear antibodies, extractible nuclear antigen, and human immunodeficiency virus (HIV), and a tick-borne disease panel yielded no abnormalities. Lumbar puncture revealed the following (reference ranges provided parenthetically): protein, 111 mg/dL (0-35 mg/dL); total nucleated cells, 27/mL (0-5/mL) with 93% lymphocytes (40%-80%); and glucose, 71 mg/dL (60% of blood value; the patient's blood glucose level was 143 mg/dL [70-140 mg/dL]). Classic albuminocytologic dissociation would include an elevated CSF protein level without an elevated CSF white blood cell count. Which one of the following is the most likely diagnosis at this point? a. Motor neuron disease b. Multiple sclerosis c. Neurosyphilis d. Ischemic stroke e. Poliomyelitis Motor neuron disease can present with primarily upper or lower motor neuron signs or with both upper and lower signs simultaneously. Which one of the following is the most specific test for evaluation of the patient's condition? a. CSF-Venereal Disease Research Laboratory (CSF-VDRL) test b. Serum rapid plasma reagin (RPR) test c. CSF fluorescent treponemal antibody absorption (CSF-FTA-ABS) test d. Magnetic resonance imaging (MRI) of the brain e. C-reactive protein measurement Examination of the cerebrospinal fluid is essential during evaluation for neurosyphilis. Neurosyphilis: a comparative study of the effects of infection with human immunodeficiency virus...