Peripheral neuropathy

Peripheral neuropathy is damage to the peripheral nerves, the nerves that carry signals between the brain and spinal cord and the rest of the body. It may affect one nerve, several nerves, or nerves throughout the body. It most often starts in the feet and then spreads upwards, reaching the hands later.

Different nerves carry feeling, control muscles, or manage automatic functions such as blood pressure and bladder control, so the symptoms depend on which nerves are damaged.

Symptoms are usually long-lasting but can come and go. They can include:

• Numbness and tingling in the feet or hands
• Burning, stabbing or shooting pain
• Less ability to feel heat, cold or injury
• Muscle weakness, cramps or twitching, especially in the feet
• Loss of balance and coordination
• Dizziness on standing, digestive problems, abnormal sweating or bladder problems, when the nerves that control automatic functions are affected

See a doctor soon for tingling, burning, numbness or weakness in the hands or feet, loss of balance, or a foot cut, blister or sore that is not healing. People with diabetes should have their feet and nerves checked at least once a year. A foot that is red, warm and painful may be infected and needs prompt care.

Diabetes is the most common cause: long-term high blood sugar damages nerves. Other causes include:

• Low vitamin levels, especially vitamin B12
• Heavy alcohol use
• Kidney disease, an underactive thyroid and autoimmune conditions
• Infections such as shingles, HIV and Lyme disease
• Some medicines, including some cancer treatments
• Injury to a nerve, or long pressure on it
• Inherited conditions

In many people no cause is found.

• Diabetes, especially when blood sugar stays high for long
• Heavy alcohol use and smoking
• A poor diet with low vitamin levels
• Kidney, liver or thyroid disease
• Contact with harmful chemicals or metals
• A family history of inherited nerve disease

Some cases improve when the cause is treated, while others last or get worse. Problems can include:

• Foot ulcers that become infected and, in severe cases, lead to amputation
• Falls and injuries from poor balance and numb feet
• Long-lasting nerve pain
• Fainting, or problems with heart rate and blood pressure
• Bladder, bowel or sexual problems
• Less pain than expected during a heart attack

• Keep diabetes and other conditions well controlled, and attend regular check-ups
• Limit or avoid alcohol, and do not smoke
• Eat a balanced diet
• Check your feet every day, wear shoes and socks even indoors, and keep your feet away from heat
• Avoid repeated movements or positions that press on a nerve

A doctor asks about symptoms and medicines and examines the feet and nerves. Tests to find the cause may include:

• Blood and urine tests, including blood sugar and vitamin levels
• Nerve conduction studies and electromyography (EMG), which show how well nerves and muscles carry signals
• A nerve or skin biopsy, or scans, in some cases

You may be referred to a neurologist, a specialist in nerve conditions.

Treatment depends on the cause, and not every cause can be treated. Treating the cause comes first: controlling blood sugar, stopping alcohol, changing a medicine or correcting a vitamin deficiency may allow the nerves to heal.

Nerve pain is usually treated with medicines made for nerve pain, because ordinary painkillers often do not work well. Physiotherapy, walking aids, braces or splints can help with weakness and balance. Safety at home and daily foot care matter too.