What is cauda equina syndrome?
Cauda equine syndrome is typically caused by a herniated disc in the lumbosacral region.
The spinal cord ends around the L1/L2 level. If damage occurs at this level or below, the exiting roots (the cauda equina) may be injured. This results in weakness and sensory deficits in the lower extremity (which may be asymmetric).
Bowel and bladder functions are affected as well. Because the compression is of the nerve roots, a lower motor neuron pattern of deficits is seen. Patellar and ankle reflexes may be absent.
The cauda equina syndrome is a rare but serious clinical complex of low back pain, lower limb motor weakness, and saddle area anesthesia (S4) with bowel and/or bladder incontinence.
The syndrome most commonly results from central intervertebral disc herniation into the sacral nerve roots.
Rarely, advanced ankylosing spondylitis and malignancy may also cause the cauda equina syndrome.
The diagnosis of this rare syndrome requires an urgent MRI and a neurosurgical consultation.
Radicular pain is often very prominent and occurs early in the course. It may be worse at night or in the recumbent position.
Asymmetric saddle distribution sensory loss may occur, and urinary incontinence may occur late in the course due to a flaccid bladder.
Cauda equina syndrome is reversible if intervention is initiated early in the course, so this syndrome is a neurosurgical emergency!
