7A. Carpal tunnel-syndrome
Carpal tunnel syndrome is the most common cause of median nerve lesion. It’s a compression neuropathy due to entrapment of the median nerve within the carpal tunnel at the wrist. Demyelination of the median nerve occurs.
The risk factors are:
- Obesity
- Female
- Diabetes
- Pregnancy
- Certain repetitive wrist movements at work
Clinical features
Sensory symptoms are most common, but motor symptoms also occur. Sensory symptoms include numbness in the palm, palmar aspect of fingers 1 – 3 and the radial half of the 4 finger. Motor symptoms include dropping things they’re holding, weak pinching. A typical symptom is a need to shake the hand during the night because of numbness.
Diagnosis and evaluation
ENG can show demyelination (slow conduction), and ultrasound can show enlarged nerve. Tinel sign can be positive and involves worsening symptoms when tapping the carpal tunnel.
Treatment
Treatment options include splinting, steroid injection, and surgical decompression of the nerve by cutting of the carpal tunnel.