Thigh Pain (Meralgia Paresthetica) Diagnosis

A physical examination will include careful assessment of the area causing the pain. 

Doctors may need no more than a physical exam to diagnose you with meralgia paresthetica. A doctor may look for hair loss on the affected thigh, or palpate for “Tinel sign,” which involves tapping your inguinal ligament to see if symptoms worsen. Or they may have you lay on your side and apply downward pressure on your hip. This pushes the two attachments of the inguinal ligament closer together, allowing the ligament to slacken, reducing pressure on the nerve. If this manipulation relieves the pain, then meralgia paresthetica is suspected. Further, the doctor may perform pinprick and light touch testing and sketch an outline of the affected area on your thigh. When patients with meralgia paresthetica report where they hurt, it often presents as a 10x6-inch oval-shaped area on the front and side of the thigh.

Other tests beyond an office exam may provide more information. A neuromuscular ultrasound may show the site of entrapment or, in other words, where the nerve is being pinched. It can also reveal if the nerve looks swollen.

Magnets can be employed to diagnose you as well. In magnetic resonance imaging (MRI), magnetic forces line up the magnetic protons in your body. In combination with radio waves, this imaging technique allows each proton in your body to serve as if it were a pixel in a photograph. While MRI was formerly used to provide doctors pictures of tissues, organs, and bones, the emerging field of magnetic resonance neurography was mentioned in a 2018 study as useful for displaying the severity of entrapped or pinched nerves.

(Source: 123RF)

Sometimes, the art of diagnosing meralgia paresthetica comes via the process of elimination. Doctors may use an X-ray or MRI to rule out an unrelated lumbar spine problem in vertebrae or intervertebral discs that might mean the thigh pain is coming from a pinched nerve root within the spine, rather than any problem with the lateral femoral cutaneous nerve.

Another test that confirms a diagnosis of meralgia paresthetica involves electricity. Called an electromyogram/nerve conduction study (EMG/NCS), tiny needles are inserted into the muscle and pads are placed on the skin to determine whether there are alterations in the electrical current of the nerve, suggesting that it has been damaged. Specifically, tests may be run on your sensory nerve conduction velocity or somatosensory evoked potential. These tests can be useful in sorting out whether the nerve involved is another nerve or the lateral cutaneous femoral nerve itself.

Besides clinical diagnosis and EMG/NCS studies, another technique a doctor may use to confirm a diagnosis of meralgia paresthetica is a lateral cutaneous femoral nerve (LCFN) block. This can be accomplished by injecting lidocaine around the LCFN, using musculoskeletal ultrasound guided imaging or CT guidance. If pain resolves during the short time that the lidocaine is in effect, then the problem indeed comes from the lateral femoral cutaneous nerve. Blood tests may check blood sugar, lead levels, thyroid hormones, B12 and folate levels to reveal other diseases that can adversely affect nerve function.

Updated on: 03/13/19
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Thigh Pain (Meralgia Paresthetica) Treatment