A 66-year-old man comes to the office for evaluation of low back pain and difficulty walking for the past several months. The pain is worse with prolonged standing and is relieved by sitting. The pain is also less severe with walking uphill than with walking downhill. Medical history is significant for degenerative joint disease of both knees. The patient does not use tobacco, alcohol, or drugs. He takes acetaminophen as needed. His temperature is 37.2 C (98.9 F), and blood pressure is 126/76 mm Hg. His abdomen is soft and nontender. There is no spinal tenderness to palpation and a straight leg raise elicits no pain. Reflexes are 2+ in both legs. There is no Babinski sign. Dorsalis pedis pulses are full and equal in both feet. Which of the following is most helpful in diagnosing his current condition?

Question

A 66-year-old man comes to the office for evaluation of low back pain and difficulty walking for the past several months.  The pain is worse with prolonged standing and is relieved by sitting.  The pain is also less severe with walking uphill than with walking downhill.  Medical history is significant for degenerative joint disease of both knees.  The patient does not use tobacco, alcohol, or drugs.  He takes acetaminophen as needed.  His temperature is 37.2 C (98.9 F), and blood pressure is 126/76 mm Hg.  His abdomen is soft and nontender.  There is no spinal tenderness to palpation and a straight leg raise elicits no pain.  Reflexes are 2+ in both legs.  There is no Babinski sign.  Dorsalis pedis pulses are full and equal in both feet.  Which of the following is most helpful in diagnosing his current condition?

Quizplus · Accepted Answer

This patient has classic symptoms of lumbar spinal stenosis, a common cause of pain in the low back and legs. Lumbar spinal stenosis may result from any condition that narrows the spinal canal and compresses nerve roots. The most common cause is degenerative joint disease (DJD). In DJD, disc herniation and facet osteophytes impinge upon the spinal cord. This is most commonly seen in middle-aged and elderly patients. Flexion of the spine causes widening of the spinal canal, while extension causes narrowing of the canal. Therefore, the symptoms of lumbar spinal stenosis are exacerbated by extension of the spine (eg, standing and downhill walking) and improved by flexion of the spine (eg sitting and uphill walking). Weakness, sensory loss, numbness/tingling, and discomfort of the legs may all be seen. Neurologic examination may be entirely normal and only 10% of patients have a positive straight leg test. The diagnosis is confirmed radiologically. MRI demonstrates bony anatomy, neural structures, and soft tissue, making it the study of choice for suspected lumbar spinal stenosis. (Choice A) Ankle-brachial index measurements are performed to evaluate peripheral vascular disease (PVD). PVD presents with leg and buttock pain that are worse with activity and relieved by rest. On the other hand, the pain of spinal stenosis is posture-dependent, persisting when standing but improving when walking uphill. Furthermore, this patient has 2+ dorsalis pedis pulses. (Choice B) Doppler ultrasonography of the lower extremities may be performed to evaluate deep venous thrombosis. This patient's symptoms suggest lumbar stenosis and warrant a spinal MRI. (Choice D) Electromyography (EMG) and nerve conduction studies (NCS) are useful for assessing neuropathy. These tests are not necessary for diagnosing lumbar stenosis, although they may aid in evaluating nerve injury caused by this disease. (Choice E) There is a strong association between HLA-B27 and ankylosing spondylitis (AS). AS presents in young males (aged 15-30 years) and symptoms include low back pain with limited spinal mobility. Symptoms improve with exercise early in the disease. (Choice F) A history of tick bite, erythema migrans, and intermittent inflammatory arthritis is a common presentation for Lyme disease. (Choice G) Bone scans identify areas of high bone turnover and are used to evaluate metastatic disease, suspected fractures, and osteomyelitis. They are also sometimes used to evaluate chronic low back pain. They do not demonstrate soft tissue and neural structures; therefore, they are inferior to MRIs in evaluating lumbar stenosis. Educational objective: Lumbar spinal stenosis is most commonly caused by degenerative joint disease. The term "neuropathic claudication" is often used to describe lumbar stenosis. This refers to the exacerbation of leg symptoms with walking (similar to peripheral vascular disease [PVD]). However, unlike PVD, the symptoms are positional and remain while standing still. Pain is relieved by flexion of the spine. Diagnosis is made based on clinical history and classic findings on spinal MRI.

A 66-Year-Old Man Comes to the Office for Evaluation of Low