Differential Diagnosis for Left Leg Sciatica

Single Most Likely Diagnosis

• Lumbar Disc Herniation: This is the most common cause of sciatica, resulting from the herniation of the nucleus pulposus through a tear in the annulus fibrosus, putting pressure on the sciatic nerve. Symptoms include pain, numbness, and weakness in the leg.

Other Likely Diagnoses

• Lumbar Spondylosis: Degenerative changes in the lumbar spine can lead to narrowing of the spinal canal (stenosis) or intervertebral foramina, compressing the sciatic nerve and causing sciatica.
• Piriformis Syndrome: The piriformis muscle can compress the sciatic nerve, especially if it is tight or inflamed, leading to sciatica.
• Sacroiliac Joint Dysfunction: Inflammation or dysfunction of the sacroiliac joint can refer pain to the leg, mimicking sciatica.

Do Not Miss Diagnoses

• Cauda Equina Syndrome: A serious condition where the nerves in the spinal canal are compressed, leading to severe pain, numbness, and weakness in the legs, as well as bladder and bowel dysfunction. Prompt surgical intervention is often necessary.
• Spinal Infection (e.g., Abscess or Osteomyelitis): Infections in the spine can cause sciatica, and if left untreated, can lead to serious complications, including paralysis and death.
• Spinal Tumor: Tumors in the spine can compress the sciatic nerve, causing sciatica. Early diagnosis is crucial for effective treatment.

Rare Diagnoses

• Diabetic Amyotrophy: A condition associated with diabetes that can cause pain, weakness, and wasting of the muscles in the leg.
• Vasculitis (e.g., Giant Cell Arteritis): Inflammation of the blood vessels can lead to ischemia of the nerve roots, causing sciatica.
• Tarlov Cyst: A rare condition where a cyst forms in the nerve root sleeve, compressing the sciatic nerve and causing sciatica.