Tingling, numbness and pain in fingers are what can be considered common symptoms of carpal tunnel syndrome. It is a condition which in most cases is associated with injury, overuse and other causes. However, there may be another disease behind it, namely hypothyroidism, and it should not be overlooked.
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What is carpal tunnel syndrome?
The way you use your hands is controlled by your brain. The brain communicates with hands (as well as with other body parts) by means of nerves. Nerves are channels that transmit signals, and those found in limbs are part of the peripheral nervous system that is connected to the central nervous system, which comprises of the brain and the spinal cord.
The nerve serving your hand is called the median nerve: it helps you feel and move your fingers, except for the pinky and one side of the ring finger. It is found in your arm and extends to the hand which it enters through a kind of gates – the so-called carpal tunnel. The tunnel is a passage located in the wrist, and when the nerve travels through it, it is affected by the soft tissues found there. If the pressure exerted is too firm, the nerve becomes damaged and brings about symptoms, such as pain, tingling, numbness, etc. This condition is called carpal tunnel syndrome.
What is hypothyroidism?
The term is used to denote thyroid hormone deficiency. When the thyroid gland produces hormones, which are based on tyrosine, in insufficient amounts, it disrupts a lot of processes in the body, and affects the metabolic rate, development processes, etc. Actually, the thyroid gland affects almost every cell, and when it does not work properly, hypothyroidism can cause such symptoms as constipation, fatigue, weight gain (and obesity), depression, etc.
What is the link between them?
Although in most cases carpal tunnel syndrome has nothing (or almost nothing) to do with the way the thyroid gland supplies the body with hormones, in some people hypothyroidism can lead to carpal tunnel syndrome. It is not a common cause, so if all other possible causes are excluded, your doctor should ask you to check whether your thyroid gland is all right.
So how does hormone deficiency result in numbness in fingers? Since the hormones produced by the thyroid gland have a great impact on how the body uses fats, carbohydrates and other substances, i.e. affect the metabolic rate, deficiency of these hormones can be associated with fluid retention. When there’s too much fluid in tissues, they become swollen, and the pressure exerted on the median nerve increases, which leads to numbness and pain in the part of the hand controlled by the nerve.
How do I know if my pain in the hand is caused by hypothyroidism?
Peripheral neuropathy, that is having your peripheral nerves, including the median nerve, damaged, can come as a consequence of long-term hypothyroidism which was left untreated.
You can consult your GP to find out whether your thyroid gland is working properly. To do it, you can have your blood analyzed in order to see if there are enough tyrosine-based hormones. However, it is recommended that your doctor excludes all other possible causes first, because hypothyroidism causing carpal tunnel syndrome is uncommon, though not impossible.
If it is thyroid hormone deficiency that causes your hand to feel numb, then your doctor will tell what drugs can help you provide enough of these hormones. Besides, special exercises can also be used. Another important aspect of treatment is to get rid of extra pounds. It can be difficult because of the disease’s influence on the metabolic rate, but if you keep fit, you are less likely to suffer from the condition, as one of the related researches revealed.
Carpal Tunnel Syndrome in Hypothyroidism – Ncbi.nlm.nih.gov
Can hypothyroidism cause peripheral neuropathy and, if so, how is it treated? –MayoClinic.org
The effects of hypothyroidism and thyroid replacement on the development of carpal tunnel syndrome – Ncbi.nlm.nih.gov