Peripheral neuropathy in older adults: numb feet, pain and balance

The NHS explains the peripheral nervous system as the network of nerves outside the brain and spinal cord, including sensory nerves (pain and touch), motor nerves (controlling muscles) and autonomic nerves (regulating automatic functions such as blood pressure and bladder function). Neuropathy can affect one nerve (mononeuropathy), several nerves (mononeuritis multiplex) or all the nerves (polyneuropathy), the most common type, which starts with the longest nerves, so symptoms typically begin in the feet and seem to spread upwards.

NHS inform describes sensory, motor, autonomic and mononeuropathy types and notes people often have more than one at once.

The NHS lists numbness and tingling in the feet or hands, burning, stabbing or shooting pain, loss of balance and co-ordination, and muscle weakness especially in the feet. NHS inform adds being less able to feel pain or temperature changes (particularly in the feet), pins and needles, muscle cramps, wasting, foot drop that causes tripping, and for autonomic nerves: constipation or diarrhoea, feeling sick or bloated, low blood pressure causing faintness or dizziness on standing, rapid heartbeat, sweating problems, sexual problems and difficulty emptying the bladder.

For older people, loss of feeling in the feet means injuries and pressure sores may not be noticed, and balance difficulties raise the risk of falls. The NHS says to see a GP early for pain, tingling or loss of sensation in the feet, loss of balance or weakness, or a cut or ulcer on the foot that is not getting better.

The NHS says high blood sugar over time damages the tiny blood vessels supplying nerves; risk rises the longer someone has had diabetes, and is higher if sugar is poorly controlled or the person smokes, drinks large amounts of alcohol or is over 40. It adds that up to 1 in 4 people with diabetes experience some pain from nerve damage and advises people with diabetes to examine their feet regularly for open wounds, sores or chilblains.

Other causes listed by the NHS include years of excessive alcohol, low vitamin B12 or other vitamins, injury or surgery, an underactive thyroid, infections such as shingles, Lyme disease and HIV, inflammation of blood vessels, chronic liver or kidney disease, an abnormal protein in the blood (MGUS), some cancers, inherited conditions such as Charcot-Marie-Tooth disease, toxins, and immune conditions such as rheumatoid arthritis, lupus and coeliac disease. Medicines that may sometimes cause it include some chemotherapy, antibiotics such as metronidazole or nitrofurantoin taken for months, long-term phenytoin, amiodarone and thalidomide. In some people no cause is found (idiopathic neuropathy). NHS inform says that if you take a medicine known to cause neuropathy your GP may temporarily stop or reduce it, and warns never to stop a prescribed medicine without checking first.

The NHS says a GP asks about symptoms and may arrange tests to identify the underlying cause, and may refer you to a neurologist. People at highest risk, such as those with diabetes, are recommended to have regular check-ups so nerve function can be assessed.

The NHS says treatment depends on symptoms and underlying cause, and not all causes can be treated. With diabetes it may help to gain better control of blood sugar, stop smoking and cut down on alcohol. Nerve pain may be treated with prescribed neuropathic pain medicines as standard painkillers often do not work. NHS inform adds that capsaicin or menthol cream may help pain in a limited area, a lidocaine plaster may be offered for a small area of skin, and if topical measures do not work a GP may consider a neuropathic agent, which includes some types of antidepressants. Because older people can be more sensitive to drowsiness and dizziness from these medicines, doses and combinations should be reviewed regularly.

For muscle weakness, physiotherapy can help and occupational therapy can find new ways to do difficult tasks; orthotics and ankle supports can help foot drop and tripping. NHS inform lists botulinum toxin injections for excessive sweating, and urodynamic studies, medication or catheterisation for difficulty emptying the bladder. The NHS says treatment for muscle weakness may involve physiotherapy and walking aids.

The NHS says the outlook varies with the cause and nerves affected: some cases improve with time if the cause is treated, while in others the damage may be permanent or gradually worsen. Untreated, there is a risk of serious complications such as a foot ulcer that becomes infected, which can lead to gangrene and in severe cases amputation. Autonomic neuropathy affecting the heart and circulation may need treatment to raise blood pressure or, rarely, a pacemaker.

The NHS advises people with diabetes to examine their feet regularly for sores, ulcers or chilblains, and prompt attention to any wound is sensible for anyone with reduced feeling. Falls prevention and a review of balance with a physiotherapist are worthwhile for anyone with neuropathy and unsteadiness.