Peripheral Nerves Disorders
The peripheral nervous system is the division of the nervous system that consists of the nerves and ganglia on the outside of the brain and spinal cord. The primary function of the peripheral nerves is to connect the central nervous system to the limbs and organs, mostly serving as a communication relay between the brain, spinal cord and the rest of the organism. Incoming and outgoing impulses travel in the nerves similar to a telephone wire. Sensory nerves conduct information about the environment such as temperature, touches, pain and the position of extremities. Motor nerves send bioelectrical impulses to muscle, resulting in contraction and movement. Unlike the brain, the peripheral nerves are not protected by the bone of spine and skull, or by the special tissues barrier between blood and brain. Therefore, it more exposed to toxins and mechanical injuries.
Neuropathy is a condition that prevents nerves from working properly. It can cause paralysis in a case of complete laceration of nerve, although total paralysis is uncommon in patients with neuropathy. Rather, the disorder causes varying degrees of weakness and insensibility, depending on the neuropathy’s type and severity.
Peripheral neuropathy includes damage to the peripheral nerves that transmit pain and temperature sensations, and can prevent sensing that patient has been injured from a cut or other causes. Besides, pain receptors in the skin can also become over-sensitized. Therefore people may feel severe pain from normal stimuli.
There are numerous illnesses which involve peripheral nerves system. Some common examples of them include:
• Guillain-Barre´ Strohl Syndrome (It is one of the most common causes of acute neuromuscular paralysis. A severe, rising, and progressive neuropathy characterized by weakness and paresthesias)
• Chronic Inflammatory Demyelinating Polyneuropathy (CIPD)
• Diabetic Neuropathies
• Mononeuropathies (an impairment of a single nerve, typical example is Carpal Tunnel Syndrome – isolated numbness of the hands which can be caused by excessive keyboard work.
• Peripheral Nerve Injuries
• Amyotrophic Lateral Sclerosis (ALS): the Disorder of the motor nerves resulting in progressive weakness of muscles. It is the most dangerous and severe neuromuscular disorders.
• Small Fiber Neuropathies
• Occupational Neuropathies: Industrial and athletic injuries to nerves result in arm weakness and tingling.
Peripheral neuropathy can be caused by:
- Nerve compression or entrapment
- Trauma and injuries
- Fracture or dislocated bones
- Tumor (including tumors of surrounding tissues (fat, muscle, vessels) which can compress the nerve
- Intraneural hemorrhage
- Prolonged exposure to cold or radiation
- Certain medicines or toxic substances
- Vascular or collagen disorders such as atherosclerosis, lupus, scleroderma, sarcoidosis, and rheumatoid arthritis.
- In some cases, neuropathy is due to heredity, vitamin deficiency, infection, and kidney disease.
The most common symptoms of peripheral neuropathy include weakness, muscle cramps or twitching, pain without obvious causes, numbness, burning and tingling. Symptoms depend on the type of affected nerve and may be observed over a period of days, weeks, or years. Neuropathic pain is hard to control with medicines and can severely impair emotional well-being and life quality. Neuropathic pain is frequently worse at night, seriously disordering sleep and adding to the emotional burden of sensory nerve injury.
Motor nerve disorders cause muscle weakness, including painful cramps and twitching, muscle degeneration, and changes in the skin and hair.
Sensory nerve disorders may result in a general feeling of numbness, mainly in the hands and feet. Damage to these nerve fibers may cause insensitive to injury from a cut or that a wound is becoming infected. Moreover, patients with peripheral neuropathy may not detect pains that signal of impending heart attack or other acute conditions. Also, pain receptors can become oversensitized and that patients may feel severe pain from routine stimuli.
Neuropathy is difficult to diagnose, and it requires a thorough and comprehensive examination of all organ systems. Doctor will take a full medical history and perform a physical and neurologic examination that may include:
- Checking of tendon reflexes
- Checking of muscle strength and tone
- Ability to feel certain sensations, posture and moves coordination
Additionally, doctor may request the following tests:
- Blood tests to check level of vitamin B12
- Thyroid function tests (blood tests to check level of thyroid hormones)
- Electromyography (EMG) a procedure that measures the electrical discharges produced in muscles
- A nerve conduction study, which estimates how quickly nerves transmit electrical signals. A nerve conduction study is usually used to diagnose carpal tunnel syndrome and other peripheral nerve diseases
- In rare cases, a physician may prescribe a nerve biopsy, a procedure in which a small sample of a nerve is extracted and examined for malformations. However, even a nerve biopsy may not always explain the cause of some neuropathies.
Neuropathy does not pass away unless the underlying disorders are relieved or removed. Although controlling a chronic condition may not reduce neuropathy, it can play an essential role in managing of the neuropathy.
Depending on the cause, neuropathy may be treated by pharmacotherapy, vitamin or other nutrients supplements, physical or occupational therapy, surgery. The most important thing is treating of underlying conditions. For example:
Diabetes. In the case of diabetes, a patient with his physician must “work together” to keep blood sugar level as close to normal ranges as possible. Maintaining normal blood sugar levels supports protection of nerves.
Vitamin deficiency. If neuropathy is the outcome of a vitamin deficiency, a doctor may prescribe injections of the certain vitamin. In the case of pernicious anemia, a patient needs regular injections of B12-vitamin for the rest of life, and perhaps additional vitamin supplements.
Autoimmune disorder. If neuropathy is caused by a prolonged inflammatory or autoimmune process, neuropathy treatment will be aimed at normalization and modulation of the immune response.
Nerve pressure. Treatment will likely concentrate on adding ergonomic positions, desks or keyboards to home or office, changing the way of holding tools or instruments, or taking a break from certain activities or sports. In extreme cases of nerve compression, surgery is requered.
Toxic substances or medications. If toxins or some drugs caused the neuropathy, it is critical to avoid further exposure to that toxins.
Peripheral nerve dysfunctions caused by tumors or traumas as well as compressive conditions can sometimes be treated surgically. Regarding diabetic neuropathy, surgeons may consider implantation a spinal cord stimulator if a patient has medically refractory pain.