Diagnosis and Management of Cauda Equina Syndrome

Clinical Diagnosis

The American College of Radiology recommends that absent lower limb reflexes with a sensory level at L5 strongly suggests cauda equina syndrome, which results from dysfunction of the sacral and lumbar nerve roots within the vertebral canal secondary to nerve root compression 1
The most common cause of cauda equina syndrome is lumbar disc herniation at the L4-L5 and L5-S1 levels, though other etiologies include neoplasm, infection/inflammation, spinal stenosis, and hemorrhage 1
Critical red flag symptoms to assess immediately include bladder, bowel, or sexual dysfunction, perianal or saddle numbness, back pain with or without radicular symptoms, weakness in the lower limbs, and sensory changes or numbness in the lower limbs 1
Lumbosacral plexopathy causes weakness, sensory loss, and flaccid loss of tendon reflexes in the affected distribution, and can be differentiated from radiculopathy using electrodiagnostic studies 2, 3

The American College of Radiology recommends MRI lumbar spine without IV contrast as the imaging study of choice because of its ability to accurately depict soft-tissue pathology, assess vertebral marrow, and assess spinal canal patency 1
Urgent MRI assessment is recommended in all patients who present with new-onset urinary symptoms in the context of low back pain or sciatica 1

The American College of Radiology recommends performing a focused neurological examination documenting motor strength, sensory level, presence or absence of reflexes, perianal sensation, and bladder function assessment 1
Urgent MRI lumbar spine without IV contrast should be ordered, and neurosurgery should be consulted immediately if any red flag symptoms are present 1
If cauda equina syndrome is confirmed with spinal cord compression, surgical decompression should be performed as early as possible to optimize neurological recovery 6
Early surgical intervention (within 96 hours) has been associated with improved outcomes in spinal cord injury patients 6

The American College of Radiology recommends not delaying imaging while waiting for "conservative management" in patients with absent reflexes and sensory level findings, as this suggests significant neural compromise requiring urgent evaluation 1
Do not assume the absence of bladder symptoms rules out cauda equina syndrome, as back pain with radicular symptoms and absent lower limb reflexes are other important symptoms 1
Electrodiagnostic studies are essential for differentiating radiculopathy from plexopathy 4