Carpal tunnel syndrome Causes – symptoms and Diagnosis
Causes
For most patients, the cause of their carpal tunnel syndrome is unknown. Any condition that exerts pressure on the median nerve at the wrist can cause carpal tunnel syndrome. Common conditions that can lead to carpal tunnel syndrome include obesity, pregnancy, hypothyroidism, arthritis, diabetes, and trauma. Tendon inflammation resulting from repetitive work, such as uninterrupted typing, can also cause carpal tunnel symptoms. Carpal tunnel syndrome from repetitive maneuvers has been referred to as one of the repetitive stress injuries. Some rare diseases can cause deposition of abnormal substances in and around the carpal tunnel, leading to nerve irritation. These diseases include amyloidosis, sarcoidosis, multiple myeloma and leukemia.
symptoms
Symptoms of carpal tunnel syndrome usually progress gradually over weeks and months and sometimes years. Anyone with recurrent or persistent pain, numbness and tingling, or weakness of the hand should consult a doctor for a diagnosis. Symptoms often develop as follows:
* Initial symptoms include pain in the wrist and palm side hand. Symptoms commonly occur in both hands. (Even when only one hand is painful, the other hand often shows signs of nerve conduction abnormalities on testing.)
* Early on, the patient also usually reports numbness, tingling, burning, or some combination of symptoms on the palm side of the index, middle, and ring fingers. (Typically the fifth finger has no symptoms.) Such sensations may radiate to the forearm or shoulder.
* Over time, the hand may become numb, and patients may lose the ability to feel heat and cold. Patients may experience a sense of weakness and a tendency to drop things.
* Patients may feel that their hands are swollen even though there is no visible swelling. This symptom may actually prove to be an important indicator of greater CTS severity.
Symptoms may occur not only when the hand is being used but also at night when the patient is at rest. Even in cases where work is suspected as the cause, symptoms typically first occur outside of work. In fact, the disorder may be distinguished from similar conditions by pain occurring at night after going to bed.
Diagnosis
The diagnosis of carpal tunnel syndrome is suspected based on the symptoms and the distribution of the hand numbness. Examination of the neck, shoulder, elbow, pulses, and reflexes can be performed to exclude other conditions that can mimic carpal tunnel syndrome. The wrist can be examined for swelling, warmth, tenderness, deformity, and discoloration. Sometimes tapping the front of the wrist can reproduce tingling of the hand, and is referred to as Tinel's sign of carpal tunnel syndrome. Symptoms can also at times be reproduced by the examiner by bending the wrist forward (referred to as Phalen's maneuver).
The diagnosis is strongly suggested when a nerve conduction velocity test is abnormal. This test involves measuring the rate of speed of electrical impulses as they travel down a nerve. In carpal tunnel syndrome, the impulse slows as it crosses through the carpal tunnel. A test of muscles of the extremity, electromyogram (EMG), is sometimes performed to exclude or detect other conditions that might mimic carpal tunnel syndrome.
Blood tests may be performed to identify medical conditions associated with carpal tunnel syndrome. These tests include thyroid hormone levels, complete blood counts, and blood sugar and protein analysis. X-ray tests of the wrist and hand might also be helpful.
Carpal tunnel syndrome – Definition and Description
