Posted on May 11, 2015
What is Neuropathy? Know the Symptoms and When to Seek Help
written by Holly Collins
The term neuropathy refers to diseases or malfunctions of the nerves. Any nerves in any location in the body can be damaged from injury or disease. Neuropathy is often classified according to the types or location of nerves affected and can also be classified according to the disease causing it.
The Neuropathy Association reports that one in 15 adults and children in the United States are afflicted with this disease—although many of them don’t realize it. Neuropathy is the leading cause of disability in this country and one of the most common chronic neurological diseases. Neuropathy is often misunderstood, misdiagnosed, and underdiagnosed and inadequately treated. Doctors say early diagnosis and treatment is critical to preventing and slowing the progression of the disease.
Types of Neuropathy
Peripheral neuropathy: When the nerve problem affects the nerves outside the brain and spinal cord—the extremities are most often affected: The toes, feet, legs, fingers, hands, and arms. The term proximal neuropathy has been used to refer to nerve damage that specifically causes pain in the thighs, hips, or buttocks.
Cranial neuropathy: When any of the 12 cranial nerves (nerves that exit from the brain directly) are damaged. The two specific types of cranial neuropathy are optic neuropathy and auditory neuropathy. Optic neuropathy refers to damage or disease of the optic nerve that transmits visual signals from the retina of the eye to the brain. Auditory neuropathy involves the nerve that carries signals from the inner ear to the brain and is responsible for hearing.
Autonomic neuropathy: Damage to the nerves of the involuntary nervous system, the nerves that control the heart and circulation (including blood pressure), digestion, bowel and bladder function, the sexual response, and perspiration. Nerves in other organs may also be affected.
Focal neuropathy: Focal neuropathy is restricted to one nerve or group of nerves, or one area of the body. Symptoms usually appear suddenly.
Causes of Neuropathy
The Mayo Clinic says nerve damage may be caused by a number of different diseases, injuries, and infections.
- Diabetes: Diabetes is the condition most commonly associated with neuropathy. The characteristic symptoms of peripheral neuropathy often seen in people with diabetes are sometimes referred to as diabetic neuropathy. Your risk of having diabetic neuropathy rises with age and the duration of diabetes. Neuropathy is most common in people who have had diabetes for decades and is generally more severe in those who have had difficulty controlling their diabetes or those who are overweight or have elevated blood lipids and high blood pressure.
- Vitamin deficiencies: Deficiencies of the vitamins B12 and folate as well as other B vitamins can cause damage to the nerves.
- Autoimmune neuropathy: Autoimmune diseases such as rheumatoid arthritis, systemic lupus, and Guillain-Barre syndrome can cause neuropathies.
- Post-herpetic neuralgia: Post-herpetic neuralgia, a complication of shingles, is a form of neuropathy.
- Alcoholic neuropathy: Alcoholism is often associated with peripheral neuropathy. Although the exact reasons for the nerve damage are unclear, it probably arises from a combination of damage to the nerves by alcohol itself along with the poor nutrition and associated vitamin deficiencies that are common in alcoholics.
- Genetic or inherited disorders: Genetic or inherited disorders can affect the nerves and are responsible for some cases of neuropathy.
- Amyloidosis: Amyloidosis is a condition in which abnormal protein fibers are deposited in tissues and organs. These protein deposits can lead to varying degrees of organ damage and may be a cause of neuropathy.
- Uremia: Uremia, a high concentration of waste products in the blood due to kidney failure, can lead to neuropathy.
- Drugs or medication: Certain drugs and medications can cause nerve damage. Examples include cancer therapy drugs such as vincristine, and antibiotics such as metronidazole, and isoniazid.
- Trauma/Injury: Trauma or injury to nerves, including prolonged pressure on a nerve or group of nerves, is a common cause of neuropathy. Decreased blood flow to the nerves can also lead to long-term damage.
- Tumors: Benign or malignant tumors of the nerves or nearby structures may damage the nerves directly, by invading the nerves, or cause neuropathy due to pressure on the nerves.
- Idiopathic: Idiopathic neuropathy is neuropathy for which no cause has been established. The term idiopathic is used in medicine to denote the fact that no cause is known.
Symptoms of Neuropathy
Not everyone with neuropathy shows symptoms, but certain symptoms are common. Symptoms often begin in the feet with a gradual loss of feeling, numbness, tingling, or pain and progress toward the center of the body with time. The arms or legs may also be involved. The inability to determine joint position may also occur, which can result in a fall. Extreme sensitivity to touch can be another symptom—the sensation of numbness and tingling of the skin is known as paresthesia.
The loss of sensory input from the foot means that blisters and sores on the feet may develop rapidly and not be noticed. Because there is a reduced sensation of pain, these sores may become infected and the infection may spread to deeper tissues, including bone.
When damage to the nerves that control movement occurs, symptoms will include weakness, loss of reflexes, loss of muscle mass, cramping, and/or loss of dexterity. Autonomic neuropathy, or damage to the nerves that control the function of organs and glands, manifests with a wide variety of symptoms, including:
- Nausea, vomiting, or abdominal bloating after meals;
- Urinary symptoms, such as incontinence, difficulty beginning to urinate, or feeling that the bladder was not completely emptied;
- Impotence in men;
- Dizziness or fainting;
- Constipation or diarrhea;
- Blurred vision;
- Heat intolerance or decreased ability to sweat; and
- Hypoglycemia unawareness: Low blood sugar levels (hypoglycemia) are associated with trembling, sweating, and palpitations. In people with autonomic neuropathy, these characteristic symptoms may not occur, making dangerously low blood sugar levels difficult to recognize.
The treatment of neuropathy involves measures to control the symptoms as well as treatment measures that address the underlying cause of neuropathy. Medical treatments for diabetes, autoimmune diseases, infections, kidney disease, and vitamin deficiencies are varied and are directed at the specific underlying condition. In many cases, treatment of the underlying disease can reduce or eliminate the symptoms of neuropathy. Some cases, especially those involving compression or entrapment of nerves by tumors or other conditions, can be relieved by surgery.
Control of blood glucose (sugar) levels is important in the treatment of diabetic neuropathy to help prevent further damage to nerves.
Neuropathy is preventable only when the underlying condition or cause is preventable. Studies show that long-term control of blood glucose levels is critically important in preventing the development of neuropathy and other complications of diabetes. Neuropathy that arises due to poor nutrition or alcohol abuse may be preventable if these causes can be eliminated. Genetic or inherited causes of neuropathy are not preventable.
When to Call a Doctor
Early diagnosis and treatment is the best course of action for controlling your symptoms and preventing further damage to your nerves.