She wriggled her left hand, again and again. The pins and needle sensation over her left thumb, index and middle finger felt like it almost disappeared with that move. In her haste, she dropped the needle and the thread that she was holding from between her fingers.
Azizah has been having difficulty doing her needle work for the past few months now. The pins and needles-like sharp sensation over her fingers appear often at night, and she has to wriggle her hand to get rid of it.
Azizah suffers from a condition known as carpal tunnel syndrome. Typically affecting females more than males, symptoms include sensory loss (loss of feeling) over lateral 3 fingers, or the thumb, index and middle finger – all supplied by the median nerve. This syndrome is more likely to occur during pregnancy, and patients who tend to use their hand-wrist movement often as seen in clerks and typist. Other risks factors include medical conditions such as diabetes, gout and rheumatoid arthritis, though it is not uncommon for patients to present with carpal tunnel syndrome in the absence of any risk factors.
The median nerve is a large nerve of the upper limb which supplies important muscles of the hand controlling movement of the thumb such as turning the door knob, holding a pen and even putting a thread through a needle. As the median nerve passes through the carpal tunnel, a tunnel at the base of the hand just over the wrist area, it can become compressed causing weakness of the innervated muscle as well as sensory disturbances over the first 3 fingers of the hand. The sensory deficit is often described as pins and needles and is quite specific for a median nerve injury. Wriggling the hand somewhat relieves the compressed nerve over the wrist and symptoms temporarily improve.
Some clinical tests reproduces the symptoms of carpal tunnel syndrome. Also known as provocative tests, this includes the Phalens test, reverse Phalens test and the more specific Durcan’s median nerve compression test . The Tinels test, another clinical test to detect carpal tunnel syndrome, is done by gently tapping over the wrist area at the level of the compressed nerve to cause an electric wave-like sensation which classically radiates or travels towards the tip of the first 3 fingers. Patients who present late may have loss of muscle bulk of the thumb area over the palm of the hand, due to diminished nerve supply as a result of chronic compression of the median nerve.
Occasionally, the attending doctor may perform investigations such as nerve conduction studies and electromyography which helps distinguish carpal tunnel syndrome from other median nerve entrapment syndromes. Having said that, carpal tunnel syndrome is rather a straight forward condition, and is clinically diagnosed with no need of any blood investigations or imaging modalities.
Carpal tunnel syndrome when detected early can be treated non surgically. Physiotherapy including wax therapy, nerve gliding exercises and electrical stimulation are all beneficial for early carpal tunnel syndrome. A splint is often prescribed to be worn over the wrist area to limit movement, aiming to reduce the compression of the median nerve. Patients who do not respond to these measures are often prescribed steroid injections given over the median nerve at the wrist area, to reduce the inflammation of the compressed nerve. This is a relatively safe and standard procedure which can be done in most outpatient clinic settings.
Patients who do not respond to conservative measures, or those who present late with evidence of muscle wasting, require surgery to decompress the inflamed nerve. Surgical release of the ligament which roofs over the carpal tunnel (known as the transverse carpal ligament) can be done through mini incisions via endoscopic surgery, or through the conventional open surgical release which can be done as a daycare procedure under local anesthesia. Surgery is done in a sterile operating theatre, and outcome is relatively good, though this depends very much on how early the patient presents to the doctor and the severity of their condition upon presentation.
Dr. Mohamed Faizal bin Hj Sikkandar is an orthopedic surgeon and lecturer with interest in hand and microsurgery.
[This article belongs to The Malaysian Medical Gazette. Any republication (online or offline) without written permission from The Malaysian Medical Gazette is prohibited.]