Carpal Tunnel Syndrome
Carpal tunnel syndrome is a condition caused by compression of the median nerve in the wrist. The nerve passes through a space in wrist called the carpal tunnel and is accompanied in the tunnel by a number of tendons. The nerve provides sensation in the thumb, index, middle and half of the ring fingers of the hand, as well as innervating some of the muscles of the thumb.
Carpal tunnel syndrome occurs when pressure builds up within the tunnel and compresses the nerve which then ceases to function normally, giving rise to numbness, tingling, and pain felt in the hand and fingers and occasionally in the forearm.
Often the cause is unknown but the nerve can be compressed in several ways such as swelling of the lining of the flexor tendons, called tenosynovitis; joint dislocations, fractures and arthritis can narrow the tunnel. Fluid retention during pregnancy can cause swelling in the tunnel and symptoms of carpal tunnel syndrome, which often (but not always) resolve after delivery. Thyroid conditions, rheumatoid arthritis, and diabetes are also associated with carpal tunnel syndrome.
Symptoms of Carpal Tunnel Syndrome
The symptoms of carpal tunnel syndrome are usually pain, numbness and tingling, or a combination of the three. The numbness or tingling most often takes place in the thumb, index, middle, and ring fingers. The symptoms usually are felt during the night but also may be noticed during daily activities such as driving or reading a newspaper. Patients sometimes notice they have a weaker grip, occasional clumsiness, and may drop things. In severe cases, sensation may be permanently lost and muscle may be lost at the base of the thumb (this is called thenar atrophy).
In order to diagnose a detailed history including medical conditions, work, hobbies and sport, and whether there have been any prior injuries is important. An X-ray may be taken to check for other causes of the complaints such as arthritis or a fracture. In some cases, laboratory tests may be carried out if there is a suspected medical condition that is associated with carpal tunnel syndromeElectrical studies of function of the median nerve (nerve conduction studies) may be undertaken to confirm the diagnosis and assess the severity of the condition.
Treatment of Carpal Tunnel Syndrome
Symptoms can often be relieved without surgery. Identifying and treating medical conditions, changing the patterns of hand use, or keeping the wrist splinted in a straight position may help reduce pressure on the nerve. Wearing wrist splints at night may relieve the symptoms that interfere with sleep. Anti-inflammatory medication taken by mouth or steroid injected into the carpal tunnel may help relieve the carpal tunnel symptoms.
Surgical treatment for carpal tunnel syndrome
When symptoms are severe or do not improve by other means, surgery may be required. Pressure on the nerve is reduced by dividing the ligament which forms the roof (top) of the tunnel on the palmar side of the hand and in so doing enlarge the tunnel. Following surgery, soreness around the incision may last for several weeks or months. The numbness and tingling may disappear quickly or slowly. It may take several months for strength in the hand and wrist to return to normal. Carpal tunnel symptoms may not completely resolve after surgery, especially in severe cases.