Meralgia Paresthetica

1 What is Meralgia Paresthetica?

Meralgia paresthetica, also called lateral femoral cutaneous nerve syndrome or Bernhardt-Roth syndrome is a condition in which one of the large sensory nerve that innervates the outer portion of the thigh gets compressed or entrapped.

This occurs when the lateral femoral cutaneous nerve gets "entrapped" as it passes through the inguinal ligament.

This abnormal pressure on the nerve results in tingling, numbness, and burning pain in the region where it supplies sensation – the outer and part of the front of the thigh.

The conditions that cause increased pressure on the groin area, usually enlarged bellies such as in obesity or pregnancy or wearing tight-fitted clothes are the common reason for the development of meralgia paresthetica.

Sometimes, meralgia paresthetica can also be a result of local trauma or a disease such as diabetes.

Most cases of meralgia paresthetica can be managed with conservative measures, such as wearing loose fitting clothing.

In severe conditions, the treatment that may include medications to relieve your discomfort or, rarely, surgery may be needed.

2 Symptoms

The pressure on the lateral femoral cutaneous nerve, which supplies sensation to your upper thigh, may cause these symptoms of meralgia paresthetica:

  • Burning pain on the outer part of your thigh, sometimes extending to the lateral side of your knee.
  • Tingling sensation or a feeling of numbness on the outer (lateral) part of your thigh.
  • Aching pain in the groin area or pain that spreads across the buttocks.

These symptoms usually are seen on only one side of your body and may aggravate after walking or standing for a long period.

Consult your doctor if you have pain or any other symptoms of meralgia paresthetica.

3 Causes

Meralgia paresthetica is caused by focal entrapment of the lateral femoral cutaneous nerve that supplies sensation to the surface of your outer thigh.

This nerve may become compressed, or "pinched". The lateral femoral cutaneous nerve is completely a sensory nerve and does not affect your movements or the ability to use your leg muscles.

Normally, this nerve passes through the groin area to the upper thigh without any trouble, but, in meralgia paresthetica, the lateral femoral cutaneous nerve gets trapped — often below the inguinal ligament that runs along your groin from your abdomen to your upper thigh.

The common causes of this compression include any conditions that exert increased pressure on the groin area, including:

  • Wearing tight fitting clothing such as belts, corsets, and tight pants.
  • Obesity or increased weight gain.
  • Wearing a heavy tool belt across your waist.
  • Pregnancy.
  • Scar tissue formed near the inguinal ligament as a result of injury or surgery in the past.
  • Nerve injury associated with diabetes or seat belt injury after a motor vehicle accident may also cause meralgia paresthetica.

4 Making a Diagnosis

Most cases of meralgia paresthetica can be diagnsoed by your doctor based on your medical history and a physical examination.

The following information helps you to get ready for your appointment.

Make a list of the following:

  • All the symptoms you are experiencing, including those that may seem unrelated to the reason for your appointment.
  • Key personal information, including major stresses or recent changes in life.
  • All medications, vitamins or supplements that you are on.

Prepare a list of questions you may want to ask your doctor as it can save time to discuss things you need to know in-depth.

For meralgia paresthetica, some basic questions to ask include:

  • What is likely cause of my symptoms or condition?
  • What tests may I need?
  • Is my condition likely to be temporary or chronic?
  • What is the best treatment available?
  • Are there alternatives to the primary approach you suggest?
  • How can I best manage the other health conditions?
  • Are there any restrictions that should be followed?

Your doctor will ask you some questions, which include:

  • What portion of your leg is affected?
  • Have you undergone any recent surgeries?
  • Have you had recent injuries in your hip area, such as from a seat belt during a motor vehicle accident?
  • Do you involve yourself in repetitive activities that affect your hip area, such as cycling?
  • Have you recently gained weight?
  • Have you recently been pregnant?
  • Are you a diabetic?
  • Is the burning or tingling sensation, an occasional or continuous problem?
  • What is the severity of your discomfort or pain?
  • Do any activities worsen your symptoms?
  • Is there any weakness?

If your pain bothers you much, over-the-counter (OTC) pain relievers such as acetaminophen (Tylenol, others), ibuprofen (Advil, Motrin IB, others) or aspirin may be taken. Also, avoid wearing tight fitting clothes.

Your doctor may touch the affected leg, ask you to describe your pain, and trace out the specific location of the numb or painful area on your leg.

To preclude other possible conditions, your doctor may recommend:

X-ray imaging: This diagnostic tool uses radiation to make images of your hip and pelvic area.

Electromyography: This test measures the electrical discharges produced in the muscles to evaluate and diagnose muscle and nerve disorders. During this test, a thin needle electrode, which records electrical activity is placed into the muscle. The results of this test will be normal in meralgia paresthetica, but the test may be done to exclude other disorders when the diagnosis is not clear.

Nerve conduction study: In this test, patch-style electrodes attached to your skin releases mild electrical impulses to stimulate the nerve. These electrical impulses help in diagnosis of damaged nerves.

Diagnostic nerve blockade: If pain relief is achieved from an injection of anesthesia into the region on your thigh where the lateral femoral cutaneous nerve enters, it can be confirmed that you have meralgia paresthetica. Ultrasound imaging is used to guide the needle.

5 Treatment

The treatment of meralgia paresthetica focuses on removal or treating the cause of nerve compression.

Conservative measures: Conservative measures are helpful in most people, with pain usually fading away within a few months. They include:

  • Application of heat or ice to the painful area.
  • Resting from an activity that aggravates pain.
  • Wearing loose fitting clothes and using a toolbox instead of wearing a tool belt.
  • Losing weight.
  • Taking OTC pain relievers such as acetaminophen (Tylenol, others), ibuprofen (Advil, Motrin IB, others) or aspirin.

Physical therapy: Physical therapy exercises help to strengthen the muscles of your legs and buttocks, and thus reduce hip injury.

Medications: If your symptoms persist for more than two months or if your pain is severe, treatment may include:

Corticosteroid injections: An injection of corticosteroid medication can reduce inflammation and relieve pain for some time.

Possible side effects include joint infection, nerve damage, pain, and white discoloration of the skin around the injection site.

Tricyclic antidepressants: These medications can help relieve your pain. Side effects include drowsiness, dry mouth, constipation and impaired sexual functioning.

Gabapentin (Neurontin), phenytoin (Dilantin) or pregabalin (Lyrica): These anti-seizure medications may help relieve your painful symptoms.

Side effects include constipation, nausea, dizziness, drowsiness, and lightheadedness.

Surgery: In rare cases, surgical decompression of the nerve is considered.

This is an option only for people with severe and long-lasting symptoms that do not respond to conservative treatment methods.

6 Lifestyle and Coping

Following lifestyle modifications are necessary in order to treat and prevent meralgia paresthetica:

  • Avoid wearing tight and restrictive clothing.
  • Follow a weight loss program to maintain a healthy weight.

7 Risks and Complications

The following factors may enhance your risk of developing meralgia paresthetica:

  • Being overweight: Excesseive body weight or obesity may increase the pressure on your lateral femoral cutaneous nerve.
  • Pregnancy: An enlarging belly puts extra pressure on your groin, through which the lateral femoral cutaneous nerve passes.
  • Diabetes: Nerve damage related to diabetes can lead to meralgia paresthetica.
  • Age: People of the age group of 30-60 years are at a greater risk.