What is isolated nerve dysfunction?
Isolated nerve dysfunction (IND) is a type of neuropathy, or nerve damage, that occurs in a single nerve. Technically, it is a mononeuropathy because it affects one nerve. It is usually the result of injury or infection. When swelling causes pressure on a nerve, the myelin sheath covering the nerve may be damaged. The nerve may also become entrapped or compressed. Nerve ischemia (lack of oxygen to the nerve) can also cause damage. The axon, or nerve cell, may also be damaged. When this type of injury occurs, signals back and forth to the brain can’t travel properly through the nerve.
Symptoms may include a tingling or buzzing sensation in the area to which the nerve provides innervation or a loss of movement and feeling.
IND is also called mononeuropathyor isolated mononeuritis.
IND is generally caused by an injury. Any injury that damages a nerve, such as a deep cut or blunt trauma, can result in IND. Compression or ischemia can also cause isolated nerve dysfunction. It can occur in any part of the body. Long-term swelling that causes pressure on a nerve can also cause IND.
Some common forms of IND include are found below.
| Form of IND | Description | Cause or effect |
| carpal tunnel syndrome | swelling in the wrist that puts pressure on the median nerve | the most common IND; often attributed to the repetitive wrist flexion and extension use |
| axillary nerve dysfunction | nerve damage in the shoulder | commonly occurs due to shoulder dislocation or fractures in the neck of the humerus |
| common peroneal nerve dysfunction | nerve damage in the leg leading to problems in the leg and foot | can lead to “foot drop,” which is the inability to pick up your foot when you walk |
| tarsal tunnel syndrome | nerve damage to the tibial nerve | causes numbness and tingling around the sole of the foot and ankle pain; not as common as the neuropathies mentioned above |
| cranial mononeuropathy of the cranial nerves III, VI, and VII | types of nerve damage that affect the eyes | can cause conditions such as double vision |
| femoral nerve dysfunction | damage to the nerves in the legs | can result from malpositioning during surgery, penetrating wounds such as gunshot or knife wounds, or other trauma; tumors and radiation can also result in injury to the femoral nerve |
| ulnar nerve dysfunction | damage to the nerve that allows the hand and wrist to move | is common, as the ulnar comes around the elbow and is prone to injury in that area because it is not enclosed in muscle; pain from your “funny bone” is pain from your ulnar nerve |
| radial nerve dysfunction | damage to the nerve that allows the back of the hand, triceps, and forearms to move | can occur from injury in the axilla (underarm) |
| pudendal nerve entrapment | rare, but can occur as a result of prolonged bike riding and can result in injury to the dorsal nerve of the penis | this nerve innervates the skin of the penis, and damage can lead to intense pain |
Some medical disorders can also cause nerve damage. According to Lab Tests Online, 60-70 percent of people with diabetes develop some form of neuropathy, usually in their extremities. Alcoholismmay also cause nerve damage, due to nutritional deficiencies. In the presence of a medical disorder such as diabetes or the alcoholic neuropathies, the disorder is usually not isolated to one particular nerve and will likely involve several nerves. This is known as peripheral neuropathy.
Symptoms vary depending on the location of the damaged nerve. Symptoms of IND include:
- paresthesias, or spontaneous, odd sensations that may get worse at night and include tingling, pinching, shocks, or buzzing
- loss of feeling
- pain, which may be sharp or dull
- paralysis
- weakness
- hypersensitivity to touch in the affected area
- difficulty tolerating clothing over the affected area
- difficulty grasping objects in IND affecting the hand
- a feeling that you‘re wearing socks or gloves, even when you’re not
To diagnose IND, your doctor will need to review your medical history in detail. They will then try to find out which nerve is damaged by examining your muscles and nerves.
Tests to check for IND include:
- nerve conduction tests to measure the speed at which nerves carry impulses back and forth to the brain. In nerve dysfunction, the speed at which impulses are transmitted are slowed.
- an electromyogram to check activity and responses in the muscles. In muscle disease, there are abnormal patterns of firing in the muscles.
- a nerve biopsy in which a small piece of the affected nerve is removed and examined
Imaging scans may also be done to check the internal organs, bones, and blood vessels. These scans may include:
- ultrasound
- CT scan
- MRI scan
Your doctor may also order laboratory tests to determine if your IND is caused by another health condition. Tests may include:
- a glucose test to check for diabetes
- a thyroid panel to check for thyroid gland disorders
- a CSF (cerebrospinal fluid) analysis to check for infections or abnormalities in the central nervous system
- specific tests for autoimmune disorders or infectious diseases, such as HIV/AIDS, shingles, or Lyme disease
- vitamin tests to check for deficiencies of vitamin B-12 or other vitamins
- tests for heavy metal poisoning
Treatment varies depending on the location and severity of your nerve damage. In some cases, the nerve will heal without treatment. If the IND is caused by an existing medical condition, such as diabetes, then that condition should be treated as well. Otherwise, the problem may worsen or recur. Although medical conditions such as diabetes can cause IND, these conditions are more likely to affect multiple nerves.
Your doctor may recommend one of many possible treatments.
The outlook varies depending on the severity of the nerve damage. With early treatment, the outlook may be quite good. Conditions often respond to physical therapy. Currently available diagnostic procedures such as nerve conduction studies are very effective in determining the location of the problem, and this is very useful in planning a course of treatment.
Severe nerve damage may lead to complete loss of movement, while mild damage may only cause uncomfortable sensations. Surgical decompression in carpal tunnel syndrome has been shown to completely cure the condition and lead to complete recovery. If the cause of your damage is found and treated, complete recovery is possible.
Complications of IND may include deformity. If the activity which caused the injury is not discontinued, then repeated injury may occur. People with IND may accidentally injure themselves because they have little or no sensation in certain body parts. This is the case in diabetic peripheral neuropathy.
IND is best prevented by avoiding traumatic injury. Also, take breaks when doing repetitive activities, such as typing, that may lead to carpal tunnel syndrome. Treating existing medical conditions that put you at risk for IND, such as diabetes and high blood pressure, can also help.