12-16-2008, 09:07 AM
A 47-year-old woman is evaluated for a 6-week history of myalgia in her torso and lower extremities, fatigue, and an occasional fever as high as 38.1 °C (100.5 °F). A week ago, her feet began to feel numb, and she has stumbled several times over the past 2 days. She has had a recent 2.25-kg (5-lb) weight loss, but has had no nausea, abdominal pain, or changes in bowel habits. She has no other symptoms. She takes only ibuprofen for her myalgia and arthralgia.
Her history includes an episode of low back pain with sciatica 5 years ago that resolved with physical therapy. Although she has had occasional arthralgia, she has noted no swelling of her peripheral joints.
On physical examination, she has a blood pressure of 160/94 mm Hg, a temperature of 38.2 °C (100.8 °F), a pulse rate of 90/min, and a respiration rate of 14/min. No sensory or motor deficit is noted in the upper extremities, but she reports only a dull sensation when a sharp stimulus is applied to the dorsum of the left foot. Quadriceps muscle strength is intact bilaterally, but significant extensor hallucis and eversion weakness is noted in the left foot and ankle. Achilles tendon reflexes are attenuated bilaterally. Both calves are tender. The rest of the physical examination is normal.
Laboratory studies indicate a leukocyte count of 12,500/µL with a normal differential, a hematocrit of 29% with normal erythrocyte indices, and a platelet count of 440,000/µL; serum creatinine level and urinalysis are normal. Erythrocyte sedimentation rate is 89 mm/h. A serum antinuclear antibody assay is negative.
Which of the following is the most appropriate next diagnostic step?
( A ) Lumbar puncture and cerebrospinal fluid studies
( B ) MRI of the lumbar spine
( C ) Mesenteric angiography
( D ) Antineutrophil cytoplasmic antibody assay
( E ) Electromyographic and sural nerve conduction velocity studies
Her history includes an episode of low back pain with sciatica 5 years ago that resolved with physical therapy. Although she has had occasional arthralgia, she has noted no swelling of her peripheral joints.
On physical examination, she has a blood pressure of 160/94 mm Hg, a temperature of 38.2 °C (100.8 °F), a pulse rate of 90/min, and a respiration rate of 14/min. No sensory or motor deficit is noted in the upper extremities, but she reports only a dull sensation when a sharp stimulus is applied to the dorsum of the left foot. Quadriceps muscle strength is intact bilaterally, but significant extensor hallucis and eversion weakness is noted in the left foot and ankle. Achilles tendon reflexes are attenuated bilaterally. Both calves are tender. The rest of the physical examination is normal.
Laboratory studies indicate a leukocyte count of 12,500/µL with a normal differential, a hematocrit of 29% with normal erythrocyte indices, and a platelet count of 440,000/µL; serum creatinine level and urinalysis are normal. Erythrocyte sedimentation rate is 89 mm/h. A serum antinuclear antibody assay is negative.
Which of the following is the most appropriate next diagnostic step?
( A ) Lumbar puncture and cerebrospinal fluid studies
( B ) MRI of the lumbar spine
( C ) Mesenteric angiography
( D ) Antineutrophil cytoplasmic antibody assay
( E ) Electromyographic and sural nerve conduction velocity studies