Question

A 68 year old woman has had worsening back pain for the past three months. Her pain radiates to her legs bilaterally. The pain is worst while walking or standing upright and is associated with weakness and numbness of her legs while walking. Sitting or lying down relieves the pain, but the patient also found that leaning forward over her grocery cart improved her symptoms while shopping earlier this morning. She has not had fever or bowel or bladder incontinence. Past medical history is significant for hypertension controlled with lisinopril. The patient does not smoke. Physical examination shows no tenderness along the lumbar spine and a negative straight-leg raising test. The feet are warm, and dorsalis pedis pulses are 2+ bilaterally. No saddle anesthesia is present, but the patient has weakness of the extensor hallucis longus bilaterally. Which of the following is the most likely pathological mechanism for this patient's symptoms?

A. Herniation of the nucleus pulposus against the L4 nerve roots
B. Pyogenic abscess of the epidural space in the lumbar spine
C. Atherosclerotic occlusion of the popliteal arteries
D. Malignant tumor invasion of the lumbar spine
E. Narrowing of the lumbar spinal canal

Answer 1

The symptoms and clinical findings of the case indicate lumbar spinal stenosis, which is the narrowing of the spinal canal in the lumbar region as the most likely cause of the patient's back pain and related symptoms.

Step-by-step explanation:

The 68-year-old woman's symptoms suggest a condition where there is narrowing of the lumbar spinal canal, commonly known as spinal stenosis. This condition often presents with pain radiating to the legs when walking or standing, which is relieved by sitting or leaning forward as these positions may decrease pressure on the spinal nerves. The weakness of the extensor hallucis longus, which is associated with the L5 nerve root, bilaterally points toward a compression at this level, which is often observed in lumbar spinal canal stenosis. The absence of fever and saddle anesthesia rules out infection (like a pyogenic abscess) and severe conditions like cauda equina syndrome, respectively. Also, the presence of good pulses in the feet and no signs of acute distress or systemic illness lower the suspicion for peripheral vascular disease or a malignant tumor. Considering the provided history and symptoms, the most likely pathological mechanism for this patient's symptoms is spinal stenosis, which is characterized by the narrowing of the spinal canal in the lumbar region.