Carpal Tunnel Syndrome
Carpal tunnel syndrome (CTS) is caused by compression of the median nerve within the carpal tunnel. It is the most common compression neuropathy of the upper extremity. The compression is caused by flexor tendon swelling, fracture, joint dislocation, or inflammatory arthritis. The lifetime risk is 10% with a female-to-male ratio of 3:1. Associated neck pain in patients with median nerve sensory abnormalities can be as high as 24%. Compression of the median nerve can be due to a variety of factors that results in loss of motor and sensory function along the distribution of the median nerve in the hand. In severe cases there is loss of the fine motor dexterity of the hand.
Often the pain is thought to be due to awkward wrist positioning that can occur during repetitive activities such as childcare or work-related activities. There is also an increased risk of carpal tunnel syndrome in individuals with amyloidosis, diabetes, pregnancy, gout, hypo- or hyperthyroidism, Lyme disease, and obesity. With compression of the median nerve, there is decrease blood flow which causes the nerve to misfire and breakdown leading to increasingly greater disability.
• Numbness or altered sensation of the palmar side of the thumb, index and ring fingers
• Atrophy of the thumb muscles
• Inability to pick up or manipulate small objects
• Dull, aching discomfort in the forearm or upper arm may occur in up to 45% of patients and is associated with milder carpal tunnel syndrome
• 84% of patients with confirmed CTS have altered hand sensation at night
• 82% of patients note that their altered sensation is worsened with hand movements
• Pain progresses followed by increasing numbness, tingling and/or weakness of the thumb, index and middle fingers
• Pain eventually subsides as the nerve damage worsens
• Wasting of the thumb muscles results in a “simian or ape hand” and a loss of the ability to oppose the thumb to the little finger
Other diseases that can mimic carpal tunnel syndrome include:
• Anterior interosseous nerve syndrome
• C6 or C7 radiculopathy
• Pronator syndrome
• Supracondylar process syndrome
It is important to remember that at a 2-year follow up of untreated carpal tunnel syndrome, 67% of patients remained the same electrodiagnostically with almost 8% deteriorating and 25% improving. So the most important first step is to avoid repetitive wrist and hand movements to start the healing process. This can be followed by wrist splints at a neutral angle which are most effective when used within three months of symptom onset. It is important to remember that wrist splints only at night are not as effective as full-time use. Short term non-steroidal anti-inflammatory medications or prednisone may be helpful in the short term but can be limited by unpleasant side effects such as stomach upset. Physical therapy which includes nerve and tendon gliding exercises as well as stretching can be very helpful as well. When the more conservative treatments have not yielded significant results, a steroid injection into the carpal tunnel may provide temporary relief. For a more definitive relief, ultrasound-guided nerve hydro-dissection can be very helpful.
Chow CS, Hung LK, Chiu CP, Lai KL, Lam LN, Ng ML, Tam KC, Wong KC, Ho PC.
Is symptomatology useful in distinguishing between carpal tunnel syndrome and cervical spondylosis? Hand Surg. 2005 Jul;10(1):1-5.
Panagos A. Rehabilitation Medicine Quick Reference-Spine (ed. Buschbacher R.M.) New York: Demos Publishing; 2010. p. 180-181.