Meralgia paresthetica is a painful condition that chiefly occurs due to compression (pressure or squeezing) of the lateral femoral cutaneous nerve (LFCN), the large nerve that supplies sensation to the front and side of the thigh. It is primarily characterized by tingling, aching, numbness and burning pain in the outer thigh.
Meralgia paresthetica usually arises from the compression of the lateral femoral cutaneous nerve (LFCN). The LFCN is a large sensory nerve that travels from the spinal cord through the pelvic region all the way down to the outside of the thigh. The LMCN nerve is a sensory nerve and does not affect one’s ability to use the leg muscles. The symptoms of Meralgia paresthetica mainly arises when the LFCN is compressed or squeezed.
In a healthy individual, the LMCN generally passes through the groin to the upper thigh without any trouble. But in the case of meralgia paresthetica, the LMCN mainly gets trapped under the inguinal ligament, which runs along the groin from the abdomen to the upper thigh.
There are a number of factors that come into play for the compression of the LFCN. These includes:
- Tight fitting clothes, like belts, corsets and tight pants, stockings or girdles
- Obesity or weight gain
- Wearing a heavy tool belt
- Scar tissue near the inguinal ligament due to a past injury or surgery
- Injury of the LMCN, which can be due to diabetes or seat belt injury after a motor vehicle accident
Certain causative factors that increase the risk of Meralgia paresthetica includes:
Age: people between the ages of 30 and 60 are at a higher incidence of getting meralgia.
Excessive weight: People who are overweight or obese have an increased pressure on the LMCN which increases the chances of having Meralgia.
Pregnancy: A growing belly puts added pressure on the groin, through which the LMCN passes thus aggravating the risk of Meralgia.
Diabetes: A nerve injury due to high blood sugar levels can lead to meralgia paresthetica.
Exposure To Chemicals: People who come in contact to lead on a daily basis have higher chances of developing Meralgia paresthetica.
Body Structure: People who have legs of two different lengths may develop Meralgia due to increased pressure on one leg.
Health Conditions: People with medical conditions such as hypothyroidism or alcoholism are at a higher risk of Meralgia paresthetica.
In general, one usually notices the warning signs of meralgia paresthetica only on one side of the body.The characteristic signs and symptoms of Meralgia paresthetica includes:
- Burning, tingling, stabbing, aching, or numbness in the thigh
- Pain on the outer thigh, which may run down to the outer side of the knee
- Worse pain when the thigh is touched even gently
- Worsened pain after walking or standing for long intervals of time
- Sometimes, aching in the groin that may extend to the buttock region
Diagnosis And Treatment
On noticing the above signs and symptoms, do consult a doctor immediately to get diagnosed. The doctor usually does a thorough physical check-up, reviews the past medical and surgical history and acknowledges the types of belts and clothing you wear for work or for recreational purposes. The doctor also asks about any possible exposure to lead and alcohol abuse. Next, the doctor examines the sensation of the affected thigh. He or she may ask you to describe the pain, and trace the numb or painful area on the thigh. The doctor might conduct additional examination to help rule out other causes for the symptoms. These include:
- Strength Testing
- Reflex Testing
- Blood tests to check the thyroid hormone levels, Vitamin-B levels, lead levels, and for signs of anemia and diabetes.
- Imaging studies including X-ray, CT-scan, MRI-scan and Ultrasound to check for other spinal or nerve problems, like a herniated disc.
- Nerve conduction study to evaluate how well your LMCN sends electrical impulses to the surrounding muscles
- Nerve blockade
The treatment options usually involve rectifying the underlying cause.
For moderate cases, the doctor may recommend physiotherapy for stretching and strengthening the leg muscles or abs. They may also conduct phonophoresis, a treatment therapy that uses ultrasound to help the body absorb the medication through the skin surface, or transcutaneous electrical nerve stimulation (TENS), which delivers electrical impulses through pads applied to the skin to block the pain.
In the case of chronic condition, the doctor may prescribe medications like:
- Corticosteroid shots to reduce the swelling.
- Tricyclic antidepressants and anti-seizure medications, to help relieve nerve pain.
Although rare, but in severe cases, the doctor may recommend surgery to ease pressure on the LMCN if no other treatment helps. It usually takes sometime for the pain to go away once the therapy starts but usually the patient recovers within 4 to 6 weeks.
For mild cases, the doctor may recommend certain lifestyle modifications like:
- Application of heat, ice, or taking over-the-counter pain relievers for a few days
- Weight loss
- Wearing loose-fitting clothing, especially around the upper front hip
- Avoiding girdles or belts, including tool belts