In carpal tunnel syndrome, the mechanism by which the nerve is damaged is due to the increase in the pressure within the tunnel due to intrinsic and extrinsic causes that trigger discomfort in the wrist and the hand. This increase in pressure produces a space conflict, as the tendon sheaths (covering) of the flexor tendons are inflamed within the tunnel and the blood flow of the median nerve decreases (ischaemia).
Among the traumatic causes are highlighted:
Wrist fractures. Because they deform the small bones of the wrist and can produce haematomas, as well as due to the immobilisation position of the conservative treatment.
Inflammatory diseases. Of the flexor tendons of the fingers, rheumatoid arthritis, gout or ganglions in the wrist can lead to a compression of the median nerve as it passes through the carpal tunnel.
Degenerative causes. As osteoarthritis of the carpal bones they can reduce the carpal tunnel space and cause pain and discomfort in the hand due to compression of the median nerve.
Intrinsic and extrinsic tumours of the carpal tunnel. They can trigger the appearance of clinical signs and symptoms of compression of the median nerve in the carpal tunnel.
Risk factors of Carpal Tunnel Syndrome
Age. Carpal Tunnel syndrome is diagnosed between the ages of 40 and 60 years.
Gender. Women are diagnosed with carpal tunnel syndrome more often than men. This is because the area of the carpal tunnel is relatively smaller in women than in men.
Work. The huge majority of cases of carpal tunnel syndrome are related to work. Those tasks that include repetitive wrist and finger movements, forced postures maintained in flexion or extension of the wrist, prolonged support on the heel of the hand, repetitive pressure or pincer grip movements, repetitive tapping with the heel of the hand, regular use of tools that vibrate and with hilt or handle in the heel of the hand.
Other diseases. Osteoarthritis or wrist injuries, such as burns, bone fractures, compression or pressure injuries, may increase the risk of developing carpal tunnel syndrome.
Chronic diseases. Some chronic diseases, such as diabetes, increase the risk of damage to the nerves, such as damage to the median nerve.
Inflammatory diseases. Such as rheumatoid arthritis can affect the covering that surrounds the tendons of the wrist and exercise pressure on the median nerve.
Obesity. Is a significant risk factor for the development of carpal tunnel syndrome.
Fluid retention. Increases the pressure within the carpal tunnel, which irritates the median nerve. It is common in kidney failure, amyloidosis, or heart failure.
Hormone changes. Produced during pregnancy, breastfeeding or the menopause, as well as in diseases like hypothyroidism or Cushing-s disease, among others.
Some medications. Such as oral contraceptives, cortisone, or drugs for elevated blood pressure.