Differential Diagnosis for Numbness of the Whole Leg
- Single most likely diagnosis
- Peripheral nerve compression (e.g., peroneal or sciatic nerve compression): This condition is likely due to the fact that numbness occurs in a specific position (sitting) and resolves with a change in position (standing), suggesting a mechanical cause.
- Other Likely diagnoses
- Lumbar disc herniation: A herniated disc in the lumbar spine can compress nerves, leading to numbness in the leg, which may be exacerbated by certain positions.
- Piriformis syndrome: The piriformis muscle can compress the sciatic nerve, causing numbness in the leg, especially when sitting.
- Meralgia paresthetica: Compression of the lateral femoral cutaneous nerve can cause numbness and tingling in the thigh, which may be worsened by sitting.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Cauda equina syndrome: A serious condition where the nerves in the spinal canal are compressed, requiring urgent medical attention.
- Spinal cord compression: Compression of the spinal cord can cause numbness, weakness, and other symptoms, and requires prompt treatment to prevent permanent damage.
- Deep vein thrombosis (DVT): Although less likely, DVT can cause numbness and swelling in the leg, and is a medical emergency due to the risk of pulmonary embolism.
- Rare diagnoses
- Multiple sclerosis: A chronic autoimmune disease that can cause numbness and other neurological symptoms, although it is less likely to be related to positional changes.
- Vasculitis: Inflammation of the blood vessels can cause numbness and other symptoms, but is a rare condition.
- Neuropathy due to systemic disease (e.g., diabetes, vitamin deficiency): Certain systemic diseases can cause neuropathy, leading to numbness in the leg, although these conditions often have other associated symptoms.