They are the ones responsible for transporting electrical impulses to and from the brain to the different organ systems, for the sensations of pain, touch, position sense, vibration sense, motor control, and even some autonomic functions. Any damage caused to these nerves will produce a neuropathy that is usually seen at the area of the body that the damaged nerve innervates. Damage to sensory nerves will usually produce changes in sensations, like a burning feeling, nerve pain, tingling or numbness and the lack of coordination. Damage to motor nerves will lead to a lack of muscle control, paralysis, muscle twitching or fasciculations, muscle atrophy, lack of dexterity and difficulty in breathing. Autonomic nerves, when damaged, will produce blurred vision, a decreased ability to sweat, orthostatic hypotension, a lowered ability to regulate body temperature, digestive problems, urinary problems and even male impotence.
One of the most common causes of peripheral neuropathy is diabetes. Diabetes is a metabolic disorder caused by the body’s inability to utilize glucose because of a lack of insulin as seen in Type 1 Diabetes, or the glucose can not enter the cells as seen in Type 2 Diabetes. Diabetic neuropathies arise as complications of a poor maintenance of blood sugar levels. When the level of glucose in the blood remains elevated for a long period of time, this is believed to cause the destruction of the peripheral nerves. Although these distally located nerves have the ability to regenerate themselves, the rate of destruction is often faster than the rate of their regeneration. When these nerves get destroyed, it is felt as a numbness or tingling sensation in the affected area. In diabetics, the sensation first starts in the feet and then gradually spreads to the legs until the arms are also affected. The feeling can also be described as like you are wearing an invisible sock or glove. The tingling sensation is often accompanied by nerve pain and muscle weakness, and loss of sensation, especially if the nerves affected are of the sensory types. When the extremities exhibit a loss of sensation, then they become prone to injury because no pain is felt, even if the limb gets cut or bruised. This is why with diabetics, proper foot care is always emphasized since this is the part that is often affected and neglected.
Diagnosis of a distal symmetrical neuropathy in diabetics, which is a form of peripheral neuropathy, is detected by blood tests, physical examination, and medical history reviews of the patient. The extent of damage of the nerves can be determined by nerve conduction studies and electromyography. To treat a neuropathy, one must first identify the underlying cause and manage it while providing temporary symptom relief for the patient. With diabetic patients, it is necessary to maintain low blood glucose levels so as to limit the damage it causes to the nerves. This includes having a well balanced and nutritious diet, proper exercise, and a healthy lifestyle. To ease the pain caused by the damage to the nerves, several options are available, depending on the extent of damage. Medications such as acetaminophen, ibuprofen, and aspirin are prescribed to ease nerve pain and numbness. In more severe cases, anti-seizure drugs like carbamazepine are used.
Proper foot care is also a significant preventative measure in diabetics because once the foot loses its ability to transmit sensations, it is prone to injury. An injury inflicted on the foot can produce wounds, which when left untreated, may lead to infection and inevitably, gangrene that is likely to spread on to the bones and other neighboring muscles and organ systems. To avoid further complications, it is highly recommended that the feet be kept as clean and protected as possible. They should not be kept damp because it can produce fungal infections. Any cuts or wounds seen should be treated and bandaged immediately so as to prevent any infection. Shoes should be worn with socks and should fit the feet snugly and not too tight so as not to cause friction and blisters on the feet.
Other causes of peripheral neuropathy are autoimmune disorders such as HIV or AIDS, lupus erythematosus, and rheumatoid arthritis, diseases of the kidney, diseases of the liver, bacterial or viral infections, and deficiencies in certain vitamins — specifically the B12 vitamin. Sometimes, genetics plays a role in causing a neuropathy since some disorders that cause it are also inherited. Alcohol abuse also contributes to the damage to nerves, as well as exposure to toxic substances like lead, mercury, arsenic, and other organic substances. Some medications used to treat cancer or AIDS can also cause neuropathies to occur. There are times that nerve damage can be caused by remaining in one position for a long time, like a job in an assembly line, wherein the repetitive actions can cause pressure on the nerves as seen in Carpal Tunnel Syndrome. Using power tools, crutches, casts, and other devices that may cause pressure on the peripheral nerves can also actually destroy them.
Treatment of a peripheral neuropathy usually starts with the proper diagnosis of the cause and nature of the neuropathy, which nerves are affected and how much damage has already been done to them. Treatment is not as easy as it seems since identifying the underlying cause is hard enough to do. Patients undergo a physical examination, a neurological examination, several blood tests and nerve tests just to be able to identify the main cause and extent of damage to the nerves. Sometimes, even after exhausting all tests, no cause is found. These are what are called idiopathic cases, which unfortunately do not have any available treatments yet. Nerve biopsies are also done to assess the abnormalities microscopically in the sensory fibers.
To alleviate the pain and numbness caused by the degeneration of the nerves, medications are given, the most common ones being the over-the-counter products like acetaminophen, nonsteroidal anti-inflammatory drugs such as aspirin and ibuprofen for mild symptoms. Severe cases are usually given anti-seizure medications such as gabapentin, carbamazepine and phenytoin, though these may cause dizziness and drowsiness. Lidocain patches and other topical pain killers can be prescribed for those who do not want to ingest medicines. Antidepressant medicines like amitryiptyline, nortriptyline, desipramine, and imipramine may provide relief for mild to moderate pain, but they also come with several side effects. Patients should consult with their doctors as to which medication is best for them.
Several therapies are also suggested for pain relief — for those patients who do not want to use any drugs to ease their pain, or for fear of addiction to the medication. These therapies include; transcutaneous electrical nerve stimulation – which acts as a block to nerve signals from reaching the brain, and biofeedback therapy that employs a special machine that teaches the patient to control body responses that reduce pain. Acupuncture is an alternative form of pain relief, but needs several sessions to be fully effective for chronic pain. Sometimes, the patients may even choose to be hypnotized, since suggestions intended to ease pain are given to them subconsciously during hypnosis. Relaxation techniques are also taught, since diminishing muscle tension is essential in providing relief for the pain.
There are hundreds of cases of peripheral neuropathies seen as complications of other diseases. If only utmost care was exercised for most of these cases, then these complications would not have surfaced. As with any sickness, its prevention is always the best cure.