THE CLINICAL SYNDROME

• In clinical practice, the most frequently encountered form of entrapment neuropathy is known as carpal tunnel syndrome.

• Compression of the median nerve at the wrist, where it travels through the carpal canal, is the root cause of this condition.

• The median nerve can be compromised as it travels through this closed space by flexor tenosynovitis, rheumatoid arthritis, pregnancy, amyloidosis, and other space-occupying lesions.

• These are the most common causes of compression of the median nerve at this location.

• Women are more likely to be affected than men.

• This entrapment neuropathy manifests itself as pain, numbness, paresthesias, and associated weakness in the hand and wrist, and these symptoms radiate to the thumb, index finger, middle finger, and radial half of the ring finger.

• These symptoms may also radiate proximally, into the forearm, from the area where they are trapped.

• If the condition is not treated, it can lead to a progressive motor deficit and, ultimately, flexion contracture in the fingers that are affected.

• The onset of symptoms is typically precipitated by activities that involve performing motions or applying pressure on the wrists in a repetitive manner, such as resting the wrists on the edge of a computer keyboard.

• A similar clinical presentation may be brought about by direct trauma to the median nerve as it enters the carpal tunnel.

• Recent research has shown that people who suffer from carpal tunnel syndrome have a higher incidence of abnormalities in the connective tissue coding genes than normal controls do.

• This is in comparison to the population as a whole.

SIGNS AND SYMPTOMS

Tenderness was located over the median nerve at the wrist, which was one of the physical findings.

A positive Tinel sign is typically seen over the median nerve as it travels beneath the flexor retinaculum.

When performing the Phalen maneuver, the patient is instructed to place their wrists in a position of complete and unforced flexion for at least thirty seconds.

The signs and symptoms of carpal tunnel syndrome can be brought on by performing this maneuver if the median nerve is compressed at the wrist.

However, because of the complex motion of the thumb, subtle motor deficits can easily be missed.

Weakness of thumb opposition and wasting of the thenar eminence are commonly seen in advanced cases of carpal tunnel syndrome.

In the early stages of carpal tunnel syndrome, the only other physical finding that may be present is tenderness over the median nerve.

A loss of sensation in the fingers leading up to the wrist may also be present.

TESTING

• Electromyography is able to differentiate between carpal tunnel syndrome and other conditions such as diabetic polyneuropathy and cervical radiculopathy.

• Plain radiographs should be performed on every patient who presents with carpal tunnel syndrome in order to rule out the presence of any hidden bony disorders.

• Due to the clinical presentation of the patient, it is possible that additional testing is required.

• These tests could include a complete blood count, uric acid level, erythrocyte sedimentation rate, and testing for antinuclear antibodies.

• When joint instability or a space-occupying lesion in the wrist is suspected, or when the actual cause of median nerve compression needs to be confirmed, magnetic resonance imaging of the wrist is a necessary diagnostic tool.

• Imaging with ultrasound could also be beneficial in determining the condition of the median nerve as it travels through the carpal tunnel.

• According to the findings of several studies, there is a significant relationship between the cross-sectional area of the nerve and the clinical manifestation of carpal tunnel syndrome.

• The injection technique that will be described later can be utilized both as a diagnostic tool and a treatment strategy.

DIFFERENTIAL DIAGNOSIS

• It is common practice to incorrectly diagnose carpal tunnel syndrome as arthritis of the carpometacarpal joint of the thumb, cervical radiculopathy, or diabetic polyneuropathy.

• Patients who have arthritis in the carpometacarpal joint of the thumb will have an abnormal result on the Watson test, in addition to radiographic evidence of arthritis.

• The majority of patients who suffer from cervical radiculopathy also experience motor and sensory changes in conjunction with their neck pain.

• In contrast, patients who have carpal tunnel syndrome do not experience any reflex changes, and the motor and sensory changes that they do experience are confined to the distal median nerve.

• In most cases, diabetic polyneuropathy presents itself as a symmetric sensory deficit affecting the entire hand.

• Unlike diabetic neuropathy, diabetic polyneuropathy is not restricted to the distribution of the median nerve.

• The double-crush syndrome can occur when cervical radiculopathy and median nerve entrapment both occur at the same time.

• In addition, diabetic patients frequently exhibit symptoms of carpal tunnel syndrome, and it is not unusual for diabetic polyneuropathy to be present in these patients as well.

TREATMENT

• Conservative treatment is usually effective for patients suffering from mild cases of carpal tunnel syndrome; surgery is recommended only for those with more severe symptoms.

• The initial treatment for carpal tunnel syndrome consists of splinting the wrist and taking simple analgesics, nonsteroidal anti-inflammatory drugs, or cyclooxygenase-2 inhibitors.

• The splint needs to be worn for the entirety of the night at the very least, but ideally, it should be worn around the clock.

• Carpal tunnel syndrome is thought to be caused by engaging in activities that involve repetitive motions, such as typing or hammering, and avoiding these activities can help alleviate some of the symptoms experienced by patients.

• In the event that the patient does not respond favorably to these non-invasive treatments, the next logical step would be to inject the patient's carpal tunnel with a local anesthetic and steroid.

• After that, a gentle aspiration is performed in order to locate the blood.

• If the aspiration test result is negative and there is no persistent paresthesia noted in the distribution of the median nerve, then 3 mL of solution is slowly injected into the patient while the patient is closely monitored for signs of local anesthetic toxicity.

• If the aspiration test result is positive, then the patient is given a larger dose of the local anesthetic.

• If the patient does not experience any paresthesia and the needle tip makes contact with bone, the needle is carefully removed from the periosteum, and then 3 mL of the solution is slowly injected after careful aspiration.

• The use of ultrasound guidance for the needle could potentially improve the accuracy of needle placement and help avoid needle-induced trauma to the median nerve.

COMPLICATIONS AND PITFALLS

• Inadequate treatment of carpal tunnel syndrome can lead to chronic pain and numbness, as well as a reduction or loss of functional ability.

• In the event that the coexisting reflex sympathetic dystrophy is not aggressively treated with sympathetic neural blockade, the problem may become even more severe.

• The injection of the carpal tunnel is a procedure that has a low risk of complications.

• Accidental injection into the blood vessel and persistent paresthesia as a result of needle-induced nerve trauma are the two most serious complications that can arise.

• Using a needle with a gauge of 25 or 27 enables this technique to be carried out in the presence of anticoagulation without causing any harm, although it does increase the likelihood of a hematoma developing.

• If immediate manual pressure is applied to the injection site after it has been given, the risk of developing this complication can be significantly reduced.

• It is possible to lessen the amount of post-procedure pain and bleeding by applying cold packs immediately after an injection and leaving them on for twenty minutes.