Cauda equina syndrome

Overview

Cauda equina syndrome (CES) is a rare but serious neurological condition resulting from compression of the cauda equina—a bundle of nerve roots located at the lower end of the spinal cord in the lumbar spine. These nerves control sensation and movement in the lower limbs and pelvic organs. When compressed, they can cause severe and permanent damage if not treated promptly. CES is considered a surgical emergency, as early intervention is crucial to prevent irreversible complications such as paralysis or loss of bladder and bowel control.

Causes

Cauda equina syndrome typically arises due to mechanical compression of the nerve roots. Common causes include:

• Herniated lumbar disc: Especially a large central disc herniation at L4-L5 or L5-S1 levels

• Spinal stenosis: Narrowing of the spinal canal due to degenerative changes

• Spinal trauma: Fractures or dislocations causing nerve impingement

• Spinal tumors: Either primary tumors or metastases compressing the cauda equina

• Epidural abscess or hematoma: Infections or bleeding within the spinal canal

• Post-surgical complications: Such as swelling or scarring after spinal surgery

Symptoms

Symptoms of cauda equina syndrome can develop suddenly or gradually and typically include a combination of the following:

• Severe lower back pain

• Sciatica: Radiating pain down one or both legs

• Saddle anesthesia: Numbness or tingling in the groin, inner thighs, or buttocks

• Bladder dysfunction: Difficulty starting urination, incontinence, or urinary retention

• Bowel incontinence or constipation

• Sexual dysfunction

• Lower extremity weakness or numbness: Especially in the feet or legs

Red flag symptoms such as saddle anesthesia and bladder/bowel dysfunction require urgent medical evaluation.

Diagnosis

Prompt and accurate diagnosis of cauda equina syndrome is critical. The diagnostic process typically includes:

• Clinical evaluation: Neurological examination assessing lower limb strength, reflexes, sensation, and perianal tone

• MRI of the lumbar spine: The gold standard for identifying the cause and location of nerve compression

• CT myelogram: Alternative imaging if MRI is unavailable or contraindicated

• Bladder scan or post-void residual volume: To assess urinary retention

• Electromyography (EMG): Sometimes used to assess nerve function if diagnosis is delayed

Treatment

Cauda equina syndrome is a surgical emergency, and early decompression is essential. Treatment strategies include:

• Emergency surgery: Typically a laminectomy or discectomy to relieve pressure on the cauda equina nerves

• Antibiotics: If an abscess or infection is the underlying cause

• Steroids: Sometimes administered to reduce inflammation (controversial and case-dependent)

• Pain management: Including NSAIDs and neuropathic pain medications

• Bladder and bowel care: Catheterization and bowel regimens as needed

• Rehabilitation: Physical therapy and occupational therapy to regain strength and function

Prognosis

The prognosis of cauda equina syndrome largely depends on the timing of surgical intervention. Patients treated within 24 to 48 hours of symptom onset have a significantly higher chance of recovering bladder, bowel, and motor function. Delayed treatment can lead to permanent nerve damage, including chronic pain, incontinence, sexual dysfunction, and mobility limitations. Long-term rehabilitation and follow-up are often needed to manage residual deficits and improve quality of life.