Which finding would indicate cauda equina syndrome in a patient with back pain?

Which finding would indicate cauda equina syndrome in a patient with back pain?

• A. Unexpected anal sphincter laxity
• B. Pain that radiates
• C. Normal sensory
• D. No bowel/bladder changes

Answer: (A)

Cauda equina syndrome involves compression of the sacral nerve roots (S2–S4), which disrupts bowel, bladder, and perineal function and often leads to loss of anal sphincter tone. An unexpected anal sphincter laxity directly shows loss of external anal sphincter tone due to S2–S4 involvement, a hallmark of CES. The other findings are less specific: pain that radiates can occur with simple radiculopathy; normal sensory exams and absence of bowel or bladder changes argue against CES. This sign should trigger urgent imaging and neurosurgical evaluation.

Cauda equina syndrome involves compression of the sacral nerve roots (S2–S4), which disrupts bowel, bladder, and perineal function and often leads to loss of anal sphincter tone. An unexpected anal sphincter laxity directly shows loss of external anal sphincter tone due to S2–S4 involvement, a hallmark of CES. The other findings are less specific: pain that radiates can occur with simple radiculopathy; normal sensory exams and absence of bowel or bladder changes argue against CES. This sign should trigger urgent imaging and neurosurgical evaluation.