July 16, 2007

Meralgia Paresthetica

A muscular construction worker presented with low back pain and lateral left leg pain and numbness. Initially the physicians operated under the assumption the pain was caused by a kidney stone and he was admitted to the medicine service. After his renal CT and lumbar spine MRI were negative, but his pain persisted, neurology was consulted. On exam he had no weakness when full effort was given. His reflexes were normal. His only positive finding was an area of sensation loss consistent with the lateral femoral cutaneous nerve. A pelvic MRI was negative for a compressive lesion. Additional history revealed that he regularly wears a tool belt and he was exerting himself when the pain began. Clinically his syndrome was most consistent with meralgia paresthetica. It is caused by compression injury of the lateral femoral cutaneous nerve, usually as it passes under the inguinal ligament. Treatment includes NSAIDs, rest, and addressing the cause, e.g. obesity, posture, or tool belt. A local anesthetic nerve block can have diagnostic value, but the pain consultants for this patient balked. He was sent home with some improvement in pain and control with oral agents.

Erbay Hakan. Meralgia Paresthetica in Differential Diagnosis of Low-Back Pain. The Clinical Journal of Pain. 18:132-135.

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