Definition of carpal tunnel syndrome
Carpal tunnel syndrome is caused by chronic compression of the median nerve of the middle arm (nervus medianus) and manifests itself early in the morning with nocturnal pain in the index and middle fingers, as well as in the thumb. In the course of the disease, the musculature of the ball of the thumb shrinks (atrophy). The disease occurs more frequently in women and the peak of frequency of the initial diagnosis is in middle age.
A triggering cause for the development of carpal tunnel syndrome cannot be identified in every case, but overload and chronic tendosynovitis in rheumatoid arthritis are regarded as favourable factors. The median arm nerve can also be constricted in the case of pathological enlargement of the limbs (acromegaly). An increase in the number of new diagnoses can also be observed in women during pregnancy and in cases where carpal tunnel syndrome occurs more frequently in families.
Introduction
Every medical diagnosis consists of the patient’s medical history (anamnesis), the examination findings (clinic) and imaging procedures. There are a number of different diseases of the wrist and other nerve bottleneck diseases that must be taken into consideration when making a diagnosis. In addition, diseases of other joints must also be taken into consideration. Diagnosis is difficult if the constellation of findings is unclear, for example if two different diseases are present at the same time, or if the disease is still in its infancy and there are no signs of the disease. In such cases, false diagnoses are possible even in the case of such a well-known clinical picture as carpal tunnel syndrome.
Clinical examination
Due to the large number of possible underlying diseases, the physical examination should not be limited exclusively to the wrist examination. At the initial examination, at least the cervical spine, shoulder and elbow joint should also be examined to exclude other diseases, and possible other nerve diseases should be asked. The examination should always be performed in comparison to the other “healthy” hand.
When looking at the hand, attention should be paid to scars, as these can be an indication of a previous injury or accident. At an advanced stage, a collapsed muscle belly in the area of the ball of the thumb can already be seen. The carpal tunnel can then be checked for pressure pain.
In the early stages, night-time palmar pain and discomfort in the first three fingers are reported, which can be relieved by massaging and shaking the hands. During the further examination, the doctor uses various tests with which he can provoke discomfort in the patient. If one or more of these clinical tests are positive, the presence of carpal tunnel syndrome is very likely.
- The so-called Hoffmann-Tinel sign can be checked by lightly tapping the carpal tunnel. If the patient experiences shooting pain, the test is positive.
- The phalen sign is when pain or sensory disturbances (paresthesia) occur over a period of about one minute when the hands are bent to the palm or stretched to the back of the hand.
- Also the examination of the so-called bottle mark can bring further clarity. Here it is tested whether there is an inability to enclose a round vessel caused by an insufficient ability to abduct the thumb.
During the further examination, the doctor uses various tests with which he can provoke complaints in the patient.
If one or more of these clinical tests are positive, the presence of carpal tunnel syndrome is very likely.
- The so-called Hoffmann-Tinel sign can be checked by lightly tapping the carpal tunnel. If the patient experiences shooting pain, the test is positive.
- The phalen sign is when pain or sensory disturbances (paresthesia) occur over a period of about one minute when the hands are bent to the palm or stretched to the back of the hand.
- Also the examination of the so-called bottle mark can bring further clarity. Here it is tested whether there is an inability to enclose a round vessel caused by an insufficient ability to abduct the thumb.
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