A 65-year-old man comes to the office due to a 4-month history of periodic back pain radiating to his buttocks and thighs. The pain is exacerbated by walking or prolonged standing, although he can tolerate bicycling without significant discomfort. Associated symptoms include occasional tingling and numbness in both lower extremities. Medical history is notable for benign prostatic hyperplasia, hypertension, and hypercholesterolemia, for which he takes appropriate medications. The patient does not use tobacco, alcohol, or illicit drugs. His blood pressure is 140/80 mm Hg, pulse is 76/min, and respirations are 14/min. On examination, distal pulses are full and symmetric. Neurologic examination shows normal motor strength, deep tendon reflexes, and plantar reflexes in the lower extremities bilaterally. Which of the following is the most likely cause of this patient's condition?

Question

A 65-year-old man comes to the office due to a 4-month history of periodic back pain radiating to his buttocks and thighs.  The pain is exacerbated by walking or prolonged standing, although he can tolerate bicycling without significant discomfort.  Associated symptoms include occasional tingling and numbness in both lower extremities.  Medical history is notable for benign prostatic hyperplasia, hypertension, and hypercholesterolemia, for which he takes appropriate medications.  The patient does not use tobacco, alcohol, or illicit drugs.  His blood pressure is 140/80 mm Hg, pulse is 76/min, and respirations are 14/min.  On examination, distal pulses are full and symmetric.  Neurologic examination shows normal motor strength, deep tendon reflexes, and plantar reflexes in the lower extremities bilaterally.  Which of the following is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d2c8_bad5_bc81_636da1da9fb6_MD0003_00 This patient with back pain radiating to the thighs has symptoms typical of lumbar spinal stenosis (SS). SS is caused by narrowing of the spinal canal, leading to compression of one or more spinal roots. It is primarily seen in degenerative arthritis with osteophyte formation affecting the facet joints (spondylosis). However, other factors may contribute, including hypertrophy of the ligamentum flavum, bulging of the intervertebral discs, and spondylolisthesis (displacement of one vertebral body relative to another). Most patients are over age 60. The symptoms of SS are posture-dependent. Extension of the lumbar spine (eg, standing, walking upright) further narrows the spinal canal and worsens the symptoms, whereas lumbar flexion (eg, walking uphill, leaning on a cane) relieves the pain. The onset of pain with walking is referred to as "neurogenic claudication" as it may resemble symptoms seen in vascular claudication. However, vascular claudication causes pain with exertion and relief with rest, whereas neurogenic claudication is relieved by walking while leaning forward ("shopping cart sign"), and exercise with the spine flexed (eg, cycling) does not incite symptoms (Choice B). The diagnosis of SS can be confirmed on MRI of the spine. Most patients are treated conservatively with physical therapy and exercise, although some require surgical intervention. "shopping cart sign" (Choice A) Cervical spondylotic myelopathy presents with weakness, paresthesias, and loss of fine motor control. Neck and upper extremity symptoms are usually present, and patients will show upper motor neuron signs (eg, hyperreflexia, upgoing plantar reflex). (Choice C) Lumbar disk herniation typically causes acute back pain with unilateral radiation down the sciatic nerve to the foot (sciatica). It usually follows an inciting event, and lumbar flexion makes the pain worse. (Choice E) Vertebral metastasis presents as dull, non-radiating pain that is worse at night and not related to position or activity. Patients often have a known malignancy or systemic symptoms (eg, weight loss). (Choice F) Seronegative spondyloarthritis (eg, ankylosing spondylitis) causes pain and progressive limitation of back motion, and most often occurs in young men. Symptoms are worse with rest and improve with activity. (Choice G) Vitamin B₁₂ deficiency can cause symptoms of peripheral neuropathy but does not usually cause back pain. Educational objective: Lumbar spinal stenosis is a common cause of back pain in patients age >60. It is characterized by back pain radiating to the thighs that is worse with lumbar extension and persists while standing still. Vascular claudication is exertion-dependent and resolves with standing still.

A 65-Year-Old Man Comes to the Office Due to a 4-Month