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Meralgia Paresthetica

Basics

Description

  • Meralgia paresthetica (MP) describes an entrapment of the lateral femoral cutaneous nerve (LFCN).
  • Symptoms include pain, paresthesias, and sensory loss over the anterolateral aspect of the thigh (1).

Epidemiology

Incidence

  • MP occurs most commonly in 30- to 40-year-olds but may affect any age group (1).
  • General population incidence: 4.3/10,000 patient years (2)
  • Retrospective study from Minneapolis observed that patients with diabetes have 7-fold increase incidence (3).

Etiology and Pathophysiology

MP arises from LFCN entrapment.

  • LFCN is usually derived from L1, L2, and L3 nerve roots.
  • LFCN emerges from the lateral aspect of the psoas muscle and travels along the retroperitoneal space toward the anterior superior iliac spine (ASIS). It enters the anterior region of the thigh by passing deep to, through, or superficial to the inguinal ligament.
  • Most commonly entrapped at inguinal ligament but may occur at any place along course of LFCN

Risk Factors

  • Iatrogenic: common postsurgical complication after hip replacement, pelvic, or spine surgeries
  • Metabolic factors: diabetes, obesity, alcoholism, heavy metal poisoning
  • Mechanical factors: tight clothing/belts around waist, pregnancy, seatbelts, strenuous walking/cycling (2)

Commonly Associated Conditions

  • Pregnancy
  • Obesity
  • Sudden weight changes (up or down)
  • Hip osteoarthritis or pubic symphysis degeneration
  • Hip, pelvic, or spine surgical history
  • Retroperitoneal/pelvic mass
  • Carpal tunnel syndrome (2)

Diagnosis

History

  • Unilateral decreased sensation, pain (burning), coldness, "electric shock " sensation, or ache of anterolateral aspect of the thigh
  • May improve with sitting and worsen with prolonged standing/walking (1)
  • There should be no medial thigh or knee symptoms.

Physical Exam

  • Hypesthesia, hyperesthesia, or dysesthesia over anterolateral thigh
  • Pain or other symptoms may worsen with hip extension.
  • Tinel (percussion/compression) at inguinal ligament may reproduce symptoms (1).
  • Motor strength and appearance should be normal.
  • Deep tendon reflexes of lower extremity should be normal.

Differential Diagnosis

  • Pelvic or abdominal mass
  • Lumbar radiculopathy
  • Hip, back, or sacroiliac (SI) joint pathology
  • Trochanteric bursitis

Diagnostic Tests & Interpretation

Initial Tests (lab, imaging)

  • MP is a clinical diagnosis; no specific tests are recommended other than history and physical exam.
  • Imaging is not indicated unless alternative diagnosis is suggested by history or exam. Plain films (spine/hip/pelvis) should be normal in MP.

Follow-up tests & special considerations

Electromyography has no role in diagnosis of MP. There should be no motor involvement.

Diagnostic Procedures/Other

LFCN nerve block: rarely indicated. If symptoms are relieved by the block, it may help distinguish MP from lumbar or femoral radiculopathies.

Treatment

General Measures

  • Usually self-limited (3)
  • Reassurance and education are paramount (3).
  • AcuteAvoid tight belts/clothes.Discuss weight loss.Control risk factors (diabetes, alcohol use, heavy metal exposure).Avoid activities that exacerbate symptoms (strenuous walking/cycling).

Medication

Usually only considered for persistent symptoms past 2 months

First Line

  • NSAIDs, acetaminophen (1)[B]
  • Lidoderm patch 5% (12 hours/day)

Second Line

  • Gabapentin
  • Carbamazepine
  • SSRI/tricyclic antidepressant (TCA)

Issues for Referral

Consider referral for surgical release in patients not responding to conservative treatment or medication management (4)[C].

Additional Therapies

Local nerve blocks with local anesthetics and ± steroids can be used for temporary relief (1)[B].

Surgery/Other Procedures

Case reports suggest benefit from surgical release of the LFCN at the level of the ASIS and resection/ablation of the nerve has been proposed after failure of surgical release.

Complementary & Alternative Therapies

  • Physical therapy
  • Kinesio taping (limited data) (1)[C]
  • Acupuncture

Ongoing Care

Follow-up Recommendations

  • Not indicated unless no resolution past 2 months
  • Consider other diagnoses if persistent.

Patient Education

Education is important to reassure patients. Typical course is benign and, frequently, symptoms resolve spontaneously with conservative measures.

Prognosis

91% of patients experience symptom relief with conservative measures only.

Complications

Unremitting symptoms or complications from surgical procedures

References

1.Cheatham SW, Kolber MJ, Salamh PA. Meralgia paresthetica: a review of the literature. Int J Sports Phys Ther. 2013;8(6):883 " 893.

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2.van Slobbe AM, Bohnen AM, Bernsen RM, et al. Incidence rates and determinants in meralgia paresthetica in general practice. J Neurol. 2004;251(3):294 " 297.

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3.Parisi TJ, Mandrekar J, Dyck PJ, et al. Meralgia paresthetica: relation to obesity, advanced age, and diabetes mellitus. Neurology. 2011;77(16):1538 " 1542.

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4.Harney D, Patijn J. Meralgia paresthetica: diagnosis and management strategies. Pain Med. 2007;8(8):669 " 677.

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Codes

ICD09

  • 355.1 Meralgia paresthetica

ICD10

  • G57.10 Meralgia paresthetica, unspecified lower limb
  • G57.11 Meralgia paresthetica, right lower limb
  • G57.12 Meralgia paresthetica, left lower limb

SNOMED

  • 85007004 Meralgia paresthetica (disorder)

Clinical Pearls

  • MP describes an entrapment of the LFCN.
  • Unilateral pain (burning), numbness, coldness, electric shock sensation, or ache of anterolateral aspect of the thigh.
  • Education is important to reassure patients. The typical course is benign and, frequently, symptoms resolve spontaneously with conservative measures.