Mononeuropathy - Meralgia Paraesthetica

Question 1

Defenition

Answer 1

Localised sensory symptoms of the outer thigh caused by compression of the lateral femoral cutaneous nerve. It is a mononeuropathy

Question 2

Mononeuropathy meaning

Answer 2

Affects a single nerve

Question 3

Basic anatomy

Answer 3

Lateral femoral cutaneous nerve originates from varying combinations of L1, L2 and L3 nerve roots. Comes from behind the psoas muscle, around the surface of the iliacus muscle and under the inguinal ligament onto the thigh, just medial and inferior to the anterior superior iliac spine (ASIS).

Question 4

Presentation

Answer 4

• Abnormal sensations (dysaesthesia)
• loss of sensation (anaesthesia) in the lateral femoral cutaneous nerve distribution.
• The skin of the upper-outer thigh is affected. Patients may describe symptoms of:
• Burning
• Numbness
• Pins and needles
• Cold sensation
• There may also be localised hair loss.

Question 5

When are symptoms worse?

Answer 5

• Standing for a long duration and improving when sitting
• Extension of the hip on the affected side.

Question 6

Diagnosis

Answer 6

Clinical diagnosis
- Investigations may be used to rule out other causes e.g. Nerve room compression in spine or pelvic tumours compressing the nerve.

Question 7

Treatment

Answer 7

Conservative:
- Rest
- Looser clothing (tight clothes such as belts may add pressure to the nerve)
- Weight loss (if appropriate)
- Physiotherapy
Medical:
- Paracetamol
- NSAIDs
- Neuropathic analgesia (e.g. amitriptyline, gabapentin, pregabalin, duloxetine)
- Local injections of steroids or local anaesthetics
Surgical
- Decompression: removing pressure on nerve
- Transection - cutting the nerve
- Resection - removing the nerve