AssessmentsDegenerative disc disease
Degenerative disc disease
USMLE® Step 1 style questions USMLE
A 67-year-old man comes to the clinic because of low back and buttocks pain for 3 weeks. He has no history of trauma, lower limb weakness, stool, or urine incontinence. He is a retired construction worker. He has type II diabetes and receives metformin twice per day. Physical examination shows lower back tenderness, decreased sensation in the foot bilaterally, mild weakness of the pedal pulse bilaterally, and normal muscle tone. Straight leg test is negative. Lower back X-ray shows no abnormalities. Lower back MRI shows decreased signal intensity of lumbar inter-vertebral discs on T1-weighted images. Which of the following is the most likely cause of the patient's symptoms?