Physical Medicine and Rehabilitation for Meralgia Paresthetica Clinical Presentation

A patient whose meralgia paresthetica (MP) is idiopathic or is caused by mechanical injury near the IL may describe paresthesias or dysesthesias within the cutaneous distribution of the lateral femoral cutaneous nerve (LFCN).

• Paresthesias are abnormal sensation perceptions, such as tingling, numbness, burning, itching, cold, and warmth, that are not triggered by obvious cutaneous physical stimulation.

• Dysesthesias are distorted perceptions of ordinary tactile or painful stimuli (eg, burning, tingling, itchiness). ^[10]

• Changes in posture or prolonged sitting or standing may cause a fluctuation of symptoms. The discomfort may resolve spontaneously and reappear.

• The appearance of MP symptoms may accompany other factors, such as a motor vehicle accident, pregnancy, surgery, weight loss, and weakness. The examiner should inquire about these associations, because LFCN pathology has several etiologies, some of which are benign and others of which require urgent investigation.

Isolated lesions of the lateral femoral cutaneous nerve (LFCN) result only in abnormalities on sensory examination. Reduced perception of pinprick or dysesthesia within the receptive fields of the LFCN is typical. Often, the clinician can plot the cutaneous boundaries of the LFCN with an ink marker on the thigh of a person with meralgia paresthetica (MP). A careful neurologic examination is necessary so that it is not assumed that the patient has a benign form of MP. Hip extension may elicit symptoms, while flexion may relieve them.

• If the neurologic examination reveals abnormalities in reflexes, power, gait, or sensation outside the boundaries of the LFCN, then processes concurrently affecting other nerves are considered. For example, reduced patellar reflex, weak leg extension, and symptoms of MP indicate possible pathology within the lumbar plexus, such as a space-occupying lesion. This condition is a plexopathy, not MP.

• Application of pressure over the LFCN at the IL may elicit tenderness or exacerbate the symptoms of MP. This Tinel sign supports localization of the pathologic process to that region.

Several processes can affect the lateral femoral cutaneous nerve (LFCN) detrimentally along its course, causing sensory dysfunction perceived within its cutaneous distribution. ^[14] The processes cited below cause classical meralgia paresthetica (MP; lesion of the LFCN at IL) and pathologies that produce symptoms of MP due to lesions at various points along the LFCN. In many of these diagnoses, additional neurologic symptoms, signs, and examination findings may be present that would indicate LFCN pathology along with other nerve injuries (eg, lumbar or lumbosacral plexopathy, multiple level radiculopathy).

• Trauma

  • Acute compression of the LFCN at the IL from seatbelt forces in rapid deceleration during motor vehicle accidents

  • Pelvic fracture

• Iatrogenic - LFCN injury has been reported in the following surgical procedures:

  • Iliac crest bone grafting

  • Pelvic osteotomy

  • Shelf operations for acetabular insufficiency

  • Inguinal lymph node dissection

  • Appendectomy

  • Total abdominal hysterectomy

• Retroperitoneal subacute mechanical - The following processes may cause a plexopathy:

  • Tumor invasion

  • Hemorrhage

  • Abscess

• Obstetric/gynecologic

  • Endometriosis - MP pain recurs and abates with menses.

  • Fetal compression during the second and third trimesters

• Subacute and chronic mechanical compression or stretching at the IL - The following situations can cause classical MP:

  • Tight-fitting garments ^[2]

  • Braces, trusses

  • Carpenter's belts

  • Belts for flag carriers

  • Obesity

• Other mechanical causes, including the following:

  • Reservoir for intrathecal medications placed in the right lower abdominal quadrant (personal account)

  • Ascites

  • L2, L3 root compressions

  • In multiple radiculopathies (pathology at the nerve root), muscle groups, including lumbar paraspinal muscles supplied by the L2 or L3 nerve roots, are weak or show denervation changes on electromyogram (EMG) needle examination.

• Metabolically and immunologically related causes, including the following:

  • Diabetes

  • Plexitis

• Infectious conditions - Those associated with MP include herpes zoster.

• Idiopathic causes