In the United Kingdom, the prevalence of carpal tunnel syndrome (CTS) reaches between 70 and 160 cases per 1,000 persons(1). Tingling, numbness of the fingers, loss of grip strength... These symptoms can reveal the compression of the median nerve in the wrist. This condition often appears after 40 years of age, especially in women. But what are the causes of carpal tunnel syndrome ? If you search the origins of this condition, you’ll rarely find one single cause.
Indeed, every situation that modifies the space which passes the median nerve (located inside the wrist) can favour the development of this syndrome. The swelling of its components (flexor tendons) or, on the contrary, the narrowing of the carpal tunnel painfully compresses the nerve. So, what are its causes?
Anatomical causes associated with carpal tunnel syndrome
The fact that women more often suffer from this syndrome can be explained by anatomical reasons. Indeed, their carpal tunnel is narrower than men’s.
However, some men can present this. For example, it can be associated with constitutional abnormalities.
A trauma can cause narrowing or deformation of the carpal tunnel . Therefore, the sequelae of a wrist fracture or arthritis reduces the space as necessary for the passage of the nerve and increases its compression.
Metabolic causes of carpal tunnel syndrome
Certain conditions can increase the risk of nerve lesion , including the median nerve. In particular, diabetes: 14% of diabetic people suffer from this syndrome. This figure reaches 30% in the case of neurological complication.
Inflammatory causes of carpal tunnel syndrome
Some inflammatory conditions such as rheumatoid arthritis , as well as other infections, can inflame the synovial sheath of the flexor tendons. This swelling reduces the space available in the carpal tunnel and also compresses the median nerve.
Endocrine causes linked with carpal tunnel syndrome
Carpal tunnel syndrome can be a result of hormonal variations.
Therefore, it is important to frequently observe the development of this syndrome during the last quarter of pregnancy. Fortunately, like many symptoms, it disappears after childbirth.
Further hormonal issues can lead to CTS, such as menopause or ovarian ablation. In these cases, symptoms take longer to disappear.
Lastly, thyroid disorders (hypothyroidism or hyperthyroidism) and renal failure can be favourable environments for CTS. The increased volume of the synovial tissue excessively compresses the median nerve.
Occupational causes of CTS
Carpal tunnel syndrome is admitted as a musculoskeletal disorder. Very frequently, it leads to many sick leaves. Indeed, some manual occupations involve repetitive movements (flexion, extension, twisting of the wrist, etc.), which can aid the development of this syndrome.
Jobs related to packaging are a perfect example. Unfortunately, the list of occupations at risk is very long:
• Automotive mechanics who screw and tighten with significant efforts of the hand;
• Construction industry workers who are exposed to vibrations from machines;
• Seamstresses who repeat precise movements with angular positions of the wrist;
• Cashiers who bear heavy weights with a repetitive posture;
• People who continuously use a keyboard or a computer mouse;
• Workers who work in a cold environment, etc.
All these people overuse their wrists with inappropriate postures and are then exposed to this condition.
Recreational causes of carpal tunnel syndrome
CTS can also originate from your hobbies!
Do-it-yourself and gardening include repetitive tasks that mistreat the wrist. The lubrication of flexor tendons can then become insufficient. Frictions between the tendons and the synovial sheath consequently cause inflammation and swelling until impeding the median nerve.
Intensive practice of videos games can also lead to musculoskeletal disorders like CTS.
Sport causes of carpal tunnel syndrome
Sportspersons whose practice involves vibrations, or the holding of accessories are also concerned. Golfers, weightlifters, cyclists and racket fans can develop CTS. Inappropriate and prolonged posture during hours can have bad consequences for your wrist.
Using a wheelchair adapted to sport can also be at the origin of CTS.
It is noticeable, from all these examples, that the causes of this condition are numerous and often can’t be clearly identified. However, if you manage to recognise these at-risk practices, you could improve your posture and avoid carpal tunnel syndrome .
For more details about this general and simplified approach, here are further sources:
(1)Mansoor S, Siddiqui M, Mateen F, Saadat S, Khan ZH, Zahid M, et al. Prevalence of Obesity in Carpal Tunnel Syndrome Patients: A Cross-Sectional Survey. Cureus. 9(7):e1519.