Let us talk here about carpel tunnel syndrome (CTS), a relatively common neurological condition involving a peripheral nerve namely the median nerve. The median nerve is a long nerve which originates from the brachial plexus and runs down the arm and forearm. As it cross from the forearm to the wrist, it goes into a tunnel formed by the transverse carpel ligaments. This tunnel is called the carpel tunnel.
CTS refers to the condition when the median nerve is pinched as it tranverses the carpel tunnel. Hence CTS is nothing other than a compressive neuropathy of the median nerve across the wrist (the site of compression of course is the carpel tunnel). So what do I mean when I say compressive neuropathy? Simple it means due to external pressure on the nerve, the nerve gets compressed. When the nerve is compressed there is interruption in the flow of signals across the nerve. This causes a neuropathy and presents clinically with neuropathic symptoms. So how does CTS present clinically?
–patients may have complain of numbness involving the area of the thumb and the first two fingers (index and middle).
–at times they may not complain of numbness per se, rather have burning, tingling, pins and needle sensation and at times frank pain in the same distribution. This is especially prominent at night and may keep them from falling asleep..
–if CTS is severe, patients may develop weakness and have difficulty in gripping things or making a fist. Severe CTS causes atrophy (weakness) of the mucles supplied by the median nerve.
Etiology of CTS:
So lets now discuss some of the causes of CTS. CTS occurs when the carpel tunnel gets narrowed and the median nerve starts getting pinched. There are many causes of CTS. One of the most common is job or occupation related. CTS is frequently seen in people whose job involves repetitive motion of the wrist-just as excessive typing (manual and/or the computer), washing clothes with your hands (wringing motion of the wrists as you try to squeeze the water out) are a few of the examples. Other causes of CTS include:
1) Rheumatoid arthritis (especially if the arthritis involves the wrist).
2) Pregnancy: CTS is more common during pregnancy. The thinking is that during pregnancy, weight gain occurs and this somehow narrows the carpel tunnel.
3)Amyloidosis: patients who have amyloidosis are more prone to getting CTS.
4) Acromegaly: patients who have acromegaly ( due to excessive secretion of growth hormone from the pituitary gland) again are more prone to CTS.
5) CTS may occur after trauma or fractures involving the wrist joint.
Diagnosis and management of CTS:
The diagnosis of CTS is clinical. Your doctor shall be able to diagnose if you have CTS on the basis or your history and clinical examination. Usually no other testing is warranted. Unless there is a doubt in my mind, I do not order tests like nerve conduction studies or EMG (electromyogram or needle study). Nor is there a need to have a MRI scan of your neck. Your doctor may order one if there is doubt that the nerve is not pinched at the wrist rather higher up in the neck (this though should be detectable from the history and clinical examination).
Once the diagnosis of CTS is made, the treatment depends upon the cause. The patient is advised to avoid activities like typing (this may be difficult to avoid all together especially if it a part of your job). In any case either by modifying the way you position your hands or the amount of time you spend on the computer some benefit can be obtained. Initial treatment of CTS is usually conservative. Your doctor might advise some conventional pain medications like ibuprofen. Using wrist spints also helps and I advise my patients to wear them at night too while asleep. Patients are usually referred for physicial therapy so that they can learn better hand ergonomics. The role of injecting steroids into the carpel tunnel to lessen the inflammation is unclear. They likely do provide some relief though for a short time. Most patients recover with the above. In a few severe cases especially the ones which have weakness, surgery may be needed. The surgery usually involves cutting the carpel ligaments and making space so that the pressure on the median nerve is removed and that it can breathe.
I hope this helps some of you.
Nitin Sethi, MD