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Dr. Maria Michailidou

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                                                                        CARPAL TUNEL SYNDROME


Carpal tunnel syndrome (CTS) is a median entrapment neuropathy, that causes paresthesia, pain, numbness, and other symptoms in the distribution of the median nerve due to its compression at the wrist in the carpal tunnel. The pathophysiology is not completely understood but can be considered compression of the median nerve traveling through the carpal tunnel.It appears to be caused by a combination of genetic and environmental factors.Some of the predisposing factors include: diabetes, obesity, pregnancy, hypothyroidism, and heavy manual work or work with vibrating tools. There is, however, little clinical data to prove that lighter, repetitive tasks can cause carpal tunnel syndrom

The main symptom of CTS is intermittent numbness of the thumb, index, long and radial half of the ring fingerThe numbness often occurs at night, with the hypothesis that the wrists are held flexed during sleep. Recent literature suggests that sleep positioning, such as sleeping on one's side, might be an associated factor.t can be relieved by wearing a wrist splint that prevents flexion.Long-standing CTS leads to permanent nerve damage with constant numbness, atrophy of some of the muscles of the thenar eminence, and weakness of palmar abduction


Signs and symptoms


People with CTS experience numbness, tingling, or burning sensations in the thumb and fingers, in particular the index, middle fingers, and radial half of the ring fingers, which are innervated by the median nerve. Less-specific symptoms may include pain in the wrists or hands and loss of grip strengthboth of which are more characteristic of painful conditions such as arthritis).

Some posit that median nerve symptoms can arise from compression at the level of the thoracic outlet or the area where the median nerve passes between the two heads of the pronator teres in the forearm,but this is highly debatable. This line of thinking is an attempt to explain pain and other symptoms not characteristic of carpal tunnel syndrome. Carpal tunnel syndrome is a common diagnosis with an objective, reliable, verifiable pathophysiology, whereas thoracic outlet syndrome and pronator syndrome are defined by a lack of verifiable pathophysiology and are usually applied in the context of nonspecific upper extremity pain.

Numbness and paresthesias in the median nerve distribution are the hallmark neuropathic symptoms (NS) of carpal tunnel entrapment syndrome. Weakness and atrophy of the thenar muscles may occur if the condition remains untreated.


Causes

Most cases of CTS are of unknown causes, or idiopathic.arpal Tunnel Syndrome can be associated with any condition that causes pressure on the median nerve at the wrist. Some common conditions that can lead to CTS include obesity, oral contraceptives, hypothyroidism, arthritis, diabetes, prediabetes (impaired glucose tolerance), and trauma.Carpal tunnel is also a feature of a form of Charcot-Marie-Tooth syndrome type 1 called hereditary neuropathy with liability to pressure palsies.

Other causes of this condition include intrinsic factors that exert pressure within the tunnel, and extrinsic factors (pressure exerted from outside the tunnel), which include benign tumors such as lipomas, ganglion, and vascular malformation.Carpal tunnel syndrome often is a symptom of transthyretin amyloidosis-associated polyneuropathy and prior carpal tunnel syndrome surgery is very common in individuals who later present with transthyretin amyloid-associated cardiomyopathy, suggesting that transthyretin amyloid deposition may cause carpal tunnel syndrome.


Diagnosis

There is no consensus reference standard for the diagnosis of carpal tunnel syndrome. A combination of described symptoms, clinical findings, and electrophysiological testing is used by a majority of hand surgeons. Numbness in the distribution of the median nerve, nocturnal symptoms, thenar muscle weakness/atrophy, positive Tinel's sign at the carpal tunnel, and abnormal sensory testing such as two-point discrimination have been standardized as clinical diagnostic criteria by consensus panels of experts.A predominance of pain rather than numbness is unlikely to be caused by carpal tunnel syndrome no matter what the result of electrophysiological testing.

Electrodiagnostic testing (electromyography and nerve conduction velocity) can objectively verify the median nerve dysfunction. If these tests are normal, carpal tunnel syndrome is either absent or very, very mild.

Clinical assessment by history taking and physical examination can support a diagnosis of CTS.

Phalen's maneuver is performed by flexing the wrist gently as far as possible, then holding this position and awaiting symptoms.A positive test is one that results in numbness in the median nerve distribution when holding the wrist in acute flexion position within 60 seconds. The quicker the numbness starts, the more advanced the condition. Phalen's sign is defined as pain and/or paresthesias in the median-innervated fingers with one minute of wrist flexion. Only this test has been shown to correlate with CTS severity when studied prospectively

Tinel's sign, a classic — though less sensitive - test is a way to detect irritated nerves. Tinel's is performed by lightly tapping the skin over the flexor retinaculum to elicit a sensation of tingling or "pins and needles" in the nerve distribution. Tinel's sign (pain and/or paresthesias of the median-innervated fingers with percussion over the median nerve) is less sensitive, but slightly more specific than Phalen's sig

Durkan test, carpal compression test, or applying firm pressure to the palm over the nerve for up to 30 seconds to elicit symptoms has also been proposed


Treatment

Generally accepted treatments include: steroids either orally or injected locally, splinting, and surgical release of the transverse carpal ligament. There is no or insufficient evidence for ultrasound, yoga, lasers, B6, and exercise therapy.

Early surgery with carpal tunnel release is indicated where there is clinical evidence of median nerve denervation or a person elects to proceed directly to surgical treatment. The treatment should be switched when the current treatment fails to resolve the symptoms within 2 to 7 weeks. However, these recommendations have sufficient evidence for carpal tunnel syndrome when found in association with the following conditions: diabetes mellitus, coexistent cervical radiculopathy, hypothyroidism, polyneuropathy, pregnancy, rheumatoid arthritis, and carpal tunnel syndrome in the workplace