Diabetes
This is the commonest cause of neuropathy in developed countries. Neuropathy affects roughly half of diabetics. This usually starts with burning sensation, itching or reduced sensation in the hands and feet, otherwise known as ‘gloves and socks’ neuropathy. Diabetes causes other kinds of neuropathy as well; click here for a detailed review by Jennifer A. Langsdorf, MD of Weill Cornell.
Cancer
Cancers such as lymphoma and monoclonal gammopathy (abnormal blood proteins) cause neuropathies, too. Some medications, called chemotherapeutics, that are used to treat cancer can damage nerves and cause neuropathy. Click here for more information from Efstathia Tzatha, MD, of Memorial Sloan Kettering Cancer Center about chemotherapy-induced neuropathy.
Vitamin Problems
These are another cause of neuropathy, especially with respect to vitamins B-1, B-6 and B-12. These are important in nerve metabolism and when they are lacking the nerves suffer, leading to neuropathy with loss or impairment of neural function. Vitamin B-6 overdoses can damage nerves. This has been seen where megadoses of B-6 are included in some sports drinks, as well as in B-complex vitamins. Click here for slides by Russell Chin, MD, of Weill Cornell about nutritional neuropathies.
Alcoholism
Causes neuropathy two ways. The first is by direct toxicity to the nerves. Secondly, poor nutrition may play a role, since alcoholics often do not eat a nutritious diet, and this causes deficiencies in B vitamins and other nutrients necessary for nerve function. People with neuropathy from any cause should avoid heavy alcohol use, which can further impair the nerves.
Autoimmune Diseases
Here the normal defenses of the body turn against the cells and tissues. Some autoimmune diseases only affect one part of the body; sometimes this is the nerves. In other autoimmune disorders, multiple body tissues are affected. Examples of autoimmune diseases include Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), Sjögren’s syndrome, multifocal motor neuropathy (MMN), lupus, rheumatoid arthritis, sarcoidosis, vasculitis, and others. Click here for a slide presentation by Chafic Karam, MD, Oregon Health Sciences University, on the diagnosis of immune neuropathies specifically affecting nerve axons.
Neurotoxins
Chemicals that can damage the nerves and disrupt their functioning. Such toxins include lead, mercury, arsenic, cadmium, and botulinum and tetanus toxins and certain pesticides and industrial chemicals, as well as some medications (see below). Excess amounts of other normally helpful substances, such as zinc and vitamin B-6, harm nerves. Some sports drinks contain megavitamins and have been reported to cause vitamin B-6 toxicity. Image: Experimental and Clinical Neurotoxicology, edited by Peter S. Spencer and Herbert H. Schaumburg.
Medications
Examples are chemotherapeutics, some anticonvulsants, HIV medications (didanosine and stavudine), statin cholesterol-lowering drugs, several blood pressure medications and certain antibiotics can cause peripheral neuropathy.
Infections
Certain viral and bacterial infections can rarely cause neuropathy, either directly or indirectly, as antibodies produced by the body against the pathogens also attack normal body organs such as nerve fibers. Leprosy is a common cause of neuropathy in some tropical countries. At least ten percent of those infected with Human Immunodeficiency Virus (HIV) develop neuropathy, some because HIV medications can be toxic to nerves. Other infections associated with neuropathy include hepatitis C, Herpes varicella-zoster (shingles), diphtheria, West Nile virus, Epstein-Barr virus and Lyme disease. Shingles can be prevented with vaccination. Read more here.
Trauma or Compression
A common cause of nerve injury is physical trauma to the nerves, such as by injuries, falls, sports activities or surgery. Nerve function can also be compromised by other body parts pressing on the nerve. An example is sciatica, which is caused by a degenerated disc which allows a vertebra to press on a nerve root, causing pain in one or both legs. Another example is carpal tunnel syndrome, in which wrist structures press on nerves. This often comes from repeated activities like typing or hammering. Tumors, scars or bone spurs can also press on nerves and cause damage. Tight casts can inflict external compression that impacts nerve function.
Cancers
Lymphoma and monoclonal gammopathy (abnormal blood proteins) cause neuropathies, too. As mentioned above, some medications, called chemotherapeutics, that are used to treat cancer, can damage nerves and cause neuropathy.
Inherited/Genetic
Most neuropathies resulting from inherited disorders start in childhood. Many are due to lack of a protein necessary for the production of the myelin sheath. They may also be caused by a defective process leading to accumulation of neurotoxic substances. Examples are Charcot-Marie-Tooth disease, Fabry, metachromatic leukodystrophy and Krabbe disease. Recent research has found that in some cases of neuropathy, genes for certain proteins in the nerve cell membrane are abnormal, leading to chemical changes in the nerve cells that result in neuropathic pain. In other types of neuropathy, defects in genes can cause the nerves to be overexcitable, so that the person feels pain despite lack of injury. Genetic testing may be appropriate for some patients, if their symptoms or test results suggest they may have an inherited/genetic basis for their neuropathy. If you and other close family members have neuropathy, you may have an inherited form of neuropathy. For more information, see the Genetics section of this website.
Other Medical Conditions
These include amyloidosis and liver, thyroid and kidney diseases that can also cause neuropathy.