Pathogenesis (development of disease)
The etiopathogenesis of carpal tunnel syndrome (KTS) is multifactorial and most cases are classified as idiopathic; 50-60% of cases are bilateral (bilateral). KTS requires as a prerequisite an anatomical narrowing in the region of the carpus. The symptoms described above are caused by an increase in volume of the tunnel contents. This results in compression of the vessels, which also leads to ischemia (reduced blood flow) of the median nerve (= chronic compression neuropathy). Subsequently, edema (swelling) forms, which promotes focal demyelination (demyelination). Thus, nerve fiber lesions (nerve fiber injuries) occur.
Etiology (Causes)
Biographic causes
- Genetic burden from parents, grandparents – anatomic bottleneck; norm variants of carpal bone shape.
- Hormonal factors – pregnancy; prevalence (disease incidence) 7-43% (based on electrophysiologic diagnosis); 34% with mild to moderate KTS symptoms; mean complaint level was significantly higher after 32 weeks gestation than before
- Occupations – occupations involving repetitive (repetitive) manual activities with flexion (bending) and extension (stretching) of the wrists, by forceful grasping, or by activities in which vibrations act on the hands and arms (e.g., pneumatic tools) [factors individually or in combination](e.g., assembly line workers, meat packers, gardeners, and musicians) [recognition as an occupational disease possible].
Behavioral causes
- Caused by overwork, such as heavy mechanical work (occupational disease list; BK list):
- Exposure to hand-arm vibrations (vibrations).
- Increased effort of the hands (powerful gripping).
- Repetitive manual activities with flexion (bending) and extension (stretching) of the hands in the wrist.
- Frequent use of smartphones: frequent swiping motions, constant use of the thumb when typing with one arm, and possibly wrist flexion when looking at the screen
Disease-related causes
- Acromegaly – endocrinological disorder caused by overproduction of growth hormone (somatotropic hormone (STH), somatotropin), with marked enlargement of the body end limbs or protruding parts of the body (acras), such as the hands, feet, lower jaw, chin, nose and eyebrow ridges.
- Amyloidosis – extracellular (“outside the cell”) deposits of amyloids (degradation-resistant proteins) that can lead to cardiomyopathy (heart muscle disease; in this case, amyloid cardiomyopathy), neuropathy (peripheral nervous system disease), and hepatomegaly (liver enlargement), among other conditions.
- Arthropathic changes in carpal joints.
- Diabetes mellitus
- Hemorrhage, usually after trauma (injury).
- Ganglia (nodular collections of nerve cell bodies outside the central nervous system) at carpal joints.
- Gout (arthritis urica/uric acid-related joint inflammation or tophic gout)/hyperuricemia (elevation of uric acid levels in the blood).
- Wrist osteoarthritis
- Hand phlegmon – diffuse inflammation of the hand.
- Infectious arthritis (inflammation of the joints)
- Lipofibromatosis (fibrous bone dysplasia) – genetic disease that leads to progressive skeletal malformation.
- Mucopolysaccharidosis (MPS) – genetic storage disease, which are included in the group of lysosomal storage diseases. They are based on disorders of enzymatic degradation of acid mucopolysaccharides (glycosaminoglycans) by lysosomal hydrolases, which lead to skeletal changes
- Myxedema – common symptom of hypothyroidism (hypothyroidism); pasty (puffy; bloated) skin showing non-push-in, doughy edema (swelling) that is not positional; facial and peripheral; occurring primarily on the lower legs
- Rheumatoid arthritis – inflammatory multisystem disease, usually manifested in the form of synovitis (inflammation of the synovial membrane).
- Tenosynovialitis of the flexor tendons (tendonitis of the flexor tendons).
- Trauma (injury): mishealed fracture (radius fracture/fracture of the radius near the wrist), hypertrophic callus (delayed fracture healing).
- Tumors such as lipomas (fatty growths), ganglia, synovial cyst, or osteophytes (bone attachments)
Laboratory diagnoses – laboratory parameters that are considered independent risk factors.
- Hyperuricemia (elevation of uric acid levels in the blood).
Other causes
