Neuropathy is the term used to describe a problem with the nerves, usually the 'peripheral nerves' as opposed to the 'central nervous system' (the brain and spinal cord).
Neuropathy is seen with a number of different underlying medical conditions. It can also exist without the cause being possible to diagnose, when doctors called it 'idiopathic.'
Fast facts on neuropathy
Here are some key points about neuropathy. More detail and supporting information is in the main article.
- Neuropathy is a complication of a number of different medical conditions and is a common condition.
- Three types of nerve can be involved; autonomic nerves, motor nerves and sensory nerves.
- Sometimes single nerves, or nerve sets are affected. Bell's Palsy is a specific example of a neuropathy of the facial nerve, affecting the muscles and skin of the face.
- Physical trauma, repetitive injury, infection, metabolic problems and exposure to toxins and some drugs can all lead to neuropathy.
- Most cases of neuropathy are found in people who have diabetes. 2,3
- With neuropathy as a complication of diabetes, up to 50% of people affected may be completely without symptoms. 4,5
- Testing for neuropathy is a routine part of diabetes care.
- While neuropathy can't really be treated, the underlying causes can be targeted. 2,6
- For toxic causes, removing exposure to a toxin, or stopping a culprit drug, can halt further nerve damage.
What is neuropathy?
The term 'neuropathy' covers a wide area and many nerves, but the problem it causes depends on the type of nerves that are affected:
- Sensory nerves (the nerves that control sensation) causing cause tingling, pain, numbness, or weakness in the feet and hands
- Motor nerves (the nerves that allow power and movement) causing weakness in the feet and hands
- Autonomic nerves (the nerves that control the systems of the body eg gut, bladder) causing changes in the heart rate and blood pressure or sweating
Neuropathy has many causes, and any number of the three nerve types can be affected at any one time.
- Mononeuropathy refers to a single nerve being affected
- Polyneuropathy means several nerves are affected
Causes of neuropathy
Approximately 30% of neuropathies are 'idiopathic', or of an unknown cause7.
Many different conditions can lead to peripheral neuropathy8:
Nearly 40 drugs are known to cause neuropathy.
- Diabetes - the commonest cause of chronic peripheral neuropathy. High blood sugar levels in people with poorly controlled diabetes damage nerves.
- B12 or folate vitamin deficiencies can cause nerve damage and peripheral neuropathy.
- Drugs - such as some chemotherapy medication and medicines used to treat HIV can cause damage to peripheral nerves.
- Poisons (toxins) - insecticides and solvents can cause peripheral nerve damage.
- Cancers - peripheral neuropathy can occur in people with some cancer E.G: lymphoma and multiple myeloma.
- Alcohol excess - high alcohol levels in the body cause nerve damage.
- Chronic kidney disease - if the kidneys are not functioning normally, an imbalance of salts and chemicals can cause peripheral neuropathy.
- Chronic liver disease.
- Injuries - broken bones and tight plastercasts can put pressure directly on the nerves.
- Infections - damage can be caused to peripheral nerves by some infections including shingles, HIV infection and Lyme disease.
- Guillain-Barré syndrome is the name given to a specific type of peripheral neuropathy triggered by infection.
- Connective tissue diseases - rheumatoid arthritis, Sjögren's syndrome and systemic lupus erythematosus.
- Certain inflammatory conditions - conditions including sarcoidosis and coeliac disease can also cause peripheral neuropathy.
- Hereditary diseases - Charcot-Marie-Tooth syndrome and Friedreich's ataxia.
- Idiopathic - in a few people, no specific cause is found for their peripheral neuropathy. This is known as idiopathic peripheral neuropathy.
- Peripheral neuropathy is common.
- It is estimated that upwards of 20 million Americans suffer from this illness.
- It can occur at any age, but is more common among older adults.
- A 1999 survey found that 8-9% of Medicare recipients have peripheral neuropathy as their primary or secondary diagnosis.
- The annual cost to Medicare exceeds $3.5 billion.1
In this video by University College Dublin School of Medicine & Medical Science, Dr. Niall Tubridy, a consultant neurologist, discusses peripheral neuropathy with a patient.
The commonest cause of peripheral neuropathy is diabetes. 2,9
High blood sugar levels causes damage to the walls of the tiny blood vessels that supply oxygen and nutrients to the nerves in the ends of the hands and feet, and the essential organs in the body (eyes, kidneys, heart).3
As a result, skin becomes damaged and the loss of sensation only makes the skin of the feet more prone to damage.10
In the US, diabetic neuropathy is the primary cause of diabetic foot problems and ulcers.11 Specific estimates vary, but overall about half of people with diabetes have diabetic neuropathy.12
On the following pages we look at the symptoms of neuropathy, tests and diagnosis, treatments and prevention and the prognosis for neuropathy sufferers.