Upper Limb Neuropathy

Upper extremity neuropathy is a very common condition that manifests in weakness, soreness, and changes in the hands’ sensitivity, depending on the location of the nerve damage. One or more nerves can be affected. It can develop at any age but is most common in people who spend a lot of time at the computer.

The main cause of upper limb neuropathy is nerve compression; this can occur in places where the nerve lies shallow under the skin or passes through a narrow bony canal (for example, the radial nerve). In some cases, the nerve can also be transmitted deep in the arm. The main causes of nerve compression are:

• When the hand has been in an uncomfortable position where it is in an inverted state for a long time (during sleep, in a state of intoxication, or under anesthesia)
• Injuries to the extremities, both direct trauma to the nerve (contusion, tear, rupture) and trauma to a bone or muscle tissue, in which the nerve is compressed by bone fragments or edema, hematoma
• Consequences of injury or surgery. The nerve can be involved in the forming scar tissue and pinched in it, lack of blood circulation and, as a result, deterioration of muscle nutrition, compressing edema
• Deformation of the joints in connection with professional activities (athletes, musicians, cooks, dentists, working with vibrating instruments)
• Cervical osteochondrosis
• Frequent hypothermia
• Any swelling and inflammation in the muscles caused by infection (flu, herpes, tuberculosis, diphtheria, malaria, HIV) or endocrine diseases (diabetes mellitus)
• Mechanical compression of a nerve by a tumor (for oncology and benign tumor diseases)
• Lack of vitamins (usually vitamin B) or minerals in the body.

Symptoms 

A nerve is a channel through which information is sent from an organ to the brain about its position (organ/limb) in space, temperature, pressure, etc., and commands to act to the organ/limb are sent from the brain. In the event of nerve damage, this connection is broken, i.e., the brain does not know about the existence of a limb, incorrectly interprets (partially not reached) information, or the signal from the brain does not reach the limb. The most common symptoms are:

• weakness of the muscles of the arms, difficulty in movement, difficulty to raise the arms up (especially over the sides)
• because of this, a violation of coordination of movements develops
• changes in hand sensitivity; decreased temperature sensitivity; creeping sensation (paresthesia)
• upper limb muscle atrophy
• spastic syndrome involuntary muscle contractions, cramps, and spasms
• swelling of the limbs

Types of neuropathy. Three large main nerves pass along the human hand: the radial nerve, the median nerve, and the ulnar nerve. Depending on which nerve is affected and in what place, the disease’s picture, and the course will differ.

• Radial nerve neuropathy. The radial nerve is responsible for the outer surface of the arm and hand. It is most often injured in the area of ​​the shoulder joint or clavicle due to the fracture in the elbow bend, where the nerve passes close under the skin and is easily squeezed (e.g., when wearing a heavy bag on the elbow) in the area of ​​the wrist joint, due to a dislocation or a long uncomfortable position (palm rest).

Depending on the location of the injury, false paralysis can form when a limb in the shoulder, elbow, or wrist hangs limply. The patient cannot control the hand (or can do it by willpower but does not feel the hand at all), and there is numbness and paresthesia of the hand and a loss of skin sensitivity.

• Median nerve neuropathy. The median nerve runs along the center of the hand along its inner side and is responsible for the sensitivity and work of the entire hand, palm, and 1-3 fingers. The most common cause is hand overstrain (usually professional in musicians, seamstresses, carpenters/joiners), unusual physical exertion on the square pronator of the hand (in the wrist area), forearm injuries, and the consequences of an incorrect injection into the ulnar vein.
• Ulnar nerve neuropathy. The ulnar nerve runs parallel to the median but closer to the outer edge of the hand, controlling the hand, ring finger, and little finger. Most often, ulnar nerve neuropathy develops in people who are in a position for a long time (usually work), straining the elbows. And, for sure, everyone has hit their elbow on hard objects and felt severe pain like an electric discharge, after which the hand became numb and itchy for a while. Deforming arthrosis and other diseases of the osteochondral apparatus are also prevalent causes of neuropathy.

Causes

Radial nerve neuropathy is called sleep paralysis or drunken paralysis. A person under the influence of alcohol or drugs falls asleep in an uncomfortable position, often sitting with their hand under their head. Usually, when a nerve is compressed, the reflex of a change in posture will work, a person does not feel that their hand is lying down.

Compression of the radial nerve can also occur with honeymoon syndrome when the partner’s head is on the shoulder or forearm for a long time during sleep. When playing tennis, neurological tennis elbow can develop. The use of crutches or handcuffs can also lead to neuropathy of the radial nerve. Rarely, an injury (shoulder fracture) is the cause of neuropathy.

According to the mechanism of development, is a typical tunnel syndrome. Compression of the nerve occurs in narrow spaces (tunnels). The clinical picture- The hand hangs; there is no extension of the arm in the wrist joint. The thumb cannot be taken to the side. Sensitivity in 1-2-3 fingers of the hand is impaired.

Symptoms of radial nerve neuropathy. This disease is accompanied by movement disorders and changes in sensitivity in the innervation zone. Symptoms depend on the level of damage to the radial nerve.

Diagnostic tests and radial nerve treatment

Tests are performed  in the axillary fossa in the upper third of the shoulder:

• When raising the hand forward, the hand hangs down.
• I finger is brought to the II finger.
• It is impossible to extend the forearm and hand, abduction of 1 finger, imposition of the second finger on adjacent ones, supination of the forearm with an extended arm: flexion in the elbow joint is weakened.
• The elbow extensor reflex is lost, and the carporadial.
• Disorder of sensitivity of I, II, and partially III fingers, excluding the terminal phalanges, is expressed mildly, more often in the form of paresthesia, crawling creeps, numbness).

With neuropathy of the radial nerve in the middle third of the shoulder, the extension of the forearm, the ulnar extensor reflex are preserved; there is no disorder of sensitivity on the shoulder when the other symptoms described above are found.

With neuropathy of the radial nerve in the lower third of the shoulder and the upper third of the forearm, sensitivity on the back of the forearm may persist, the function of the extensors of the hand and fingers falls out, and sensitivity on the back of the hand is impaired. Diagnostic tests can detect damage to the radial nerve:

• In a standing position with hands down, supination of the hand and abduction of the first finger are impossible.
• It is impossible to simultaneously touch the plane with the back of the hand and fingers.
• If the hand lies on the table, palm down, and it is not possible to put the third finger on the adjacent fingers.
• When the fingers are diluted (the palms are pressed against each other by the palmar surfaces), the fingers of the affected hand are not retracted but bend and slide over the palm of a healthy hand.

The diagnosis is made by neurological examination, taking into account complaints and anamnesis of the disease. There are diagnostic tests that can reliably suggest a diagnosis.

Treatment of neuropathy of the radial nerve. Complex treatment is prescribed:

• antioxidants
• vascular therapy
• dehydration
• anticholinesterase drugs
• preparations of vitamins of group B.

Physio Balneotherapy, massage, exercise therapy, acupuncture, nerve and muscle stimulation, myotonic, and stimulus are used. Surgical treatment of neuropathy of the radial nerve is carried out only in case of complete disturbance of conduction along the nerve, violation of the integrity of the nerve.