Carpal tunnel syndrome (CTS) is a medical condition caused by compression of the median nerve as it travels through the carpel tunnel in the wrist. The “roof” of this tunnel is the transverse carpal ligament which attaches to 4 bones in the wrist. As we age, all our tissues become slightly less supple and typically the ligament tissue slowly becomes thickened and stiffer. CTS occurs more commonly in female patients, usually after the age of 45.
The true cause of carpal tunnel syndrome is unknown, but it is thought to occur due to periods of prolonged wrist flexion and therefore patients present with night time symptoms initially due to abnormal sleeping position. Patients who are pregnant or have diabetes, rheumatoid arthritis, hypothyroidism or amyloidosis are more prone to getting carpal tunnel syndrome.
The median nerve passes through this tunnel along with 9 other tendons, and as it is ultimately a limited space, any condition causing a decrease in this space is likely to cause CTS. Patients with tenosynovitis of any of the flexor tendons may experience CTS.
Symptoms of CTS are a combination of numbness, tingling, pain, or weakness and are experienced differently by all patients. That said, there is usually a very typical history, especially in early phases of the condition. Patients are woken in the early morning by symptoms of tingling and numbness (they often mention the fingers feel swollen) in the fingertips of the thumb, index and middle fingers. Occasionally the thumb side of the ring finger is also included, with the index and middle finger most commonly affected. They commonly say they have to shake their hands (or even put them in the fridge or freezer!) to improve symptoms. In established disease the numbness may be constant and some might lose strength in their hands or muscle bulk over the palm of the thumb. Severe established carpal tunnel syndrome can lead to permanent symptoms of numbness, paraesthesia, weakness and even neuropathic pain.
Making a diagnosis of CTS is done on history and clinical exam at the consultation. In atypical cases nerve conduction studies (NCS) or Electromyography (EMG) may be requested to aid the diagnosis.