Diabetic neuropathy – what you need to know

One of the most common complications of diabetes – both type 1 and type 2 – is neuropathy, which simply means nerve damage.

Your nerves are the fibres in your body that send messages, electrically and chemically, between your body and your brain, so that your body knows what to do.

Over long periods of time, high blood sugars can damage various nerve fibres in the body in different ways. We still don’t know the exact hows and whys of this, but research is ongoing, and there are clear recommendations and treatment options.

There are three types of nerves that can be damaged:

• ‘Sensory neuropathy’ is damage to nerves that detect touch or temperature.

• ‘Motor neuropathy’ is damage to nerves that help with muscle movement.

• ‘Autonomic neuropathy’ is damage to nerves that control the body’s involuntary actions, including digestion, breathing, and heart rate, among others.

SENSORY NEUROPATHY

A person with sensory neuropathy may experience numbness, pain, tingling, or loss of feeling, often in the arms, legs, hands, and feet. The symptoms usually come on slowly and gradually – you may hardly notice them. Occasionally, however, there is sudden pain.

For many reasons, feet are particularly vulnerable to neuropathy. Once neuropathy in legs and feet becomes advanced, the need for amputation is a real risk. This is why it’s so important for people with diabetes to get regular foot checks. For more about caring for your feet, see www.diabetes.org. nz/blog/steps-to-healthy-feet.

MOTOR NEUROPATHY

A feeling of unusual muscle weakness is often the main symptom of damage to motor nerves.

Proximal neuropathy is one of the more common motor neuropathies. It affects hips, buttocks, and thighs. It weakens the legs, and can make it difficult to walk or to stand up from a sitting position. Another symptom is sudden pain in your hip, buttock, or thigh. Proximal neuropathy is seen most often in older people.

With careful blood sugar management and good care, including medication and physiotherapy, proximal neuropathy can improve over months or years, although it may never go away altogether.

AUTONOMIC NEUROPATHY

This involves damage to nerves in one or more organ systems, such as the cardiovascular system, the gastrointestinal system, the reproductive system, or the urinary system.

Autonomic neuropathy is one of the least recognised complications of diabetes. There are many possible symptoms, and autonomic neuropathy can often be missed and diagnosed as something else.

Anyone with diabetes, especially if they have also been diagnosed with sensory or motor neuropathy, should also keep an eye out for or be checked for symptoms of possible autonomic neuropathy.

Signs and symptoms of autonomic neuropathies can include:

• resting tachycardia (a rapid heartbeat even when relaxed)

• ongoing hypoglycaemia unawareness

• postural hypotension (sudden blood pressure drops when moving from lying to sitting or sitting to standing)

• gustatory sweating (excessive sweating when eating, or even sometimes when thinking about eating)

• sexual dysfunction (such as erectile dysfunction or vaginal dryness)

• neurogenic bladder (a lack of bladder control because of a nerve problem)

• gastroparesis (where food stays in the stomach longer than it should)

• other gastro-intestinal issues, such as diarrhoea

• difficulty swallowing food.

FOCAL NEUROPATHY

Diabetic neuropathy often affects a wide range of nerves at once, but focal neuropathy is when there is damage to just one nerve or a small group of them. It usually, but not always, affects the torso, leg, or head, particularly the eyes. Symptoms can include double vision or other difficulties focusing, aching behind the eye, paralysis, or pain in the lower back or other places.

HOW IS NEUROPATHY DIAGNOSED?

People with diabetes, particularly those who have lived with it for many years, should be screened for neuropathy at least once a year by their GP or other healthcare professional.

Diagnosis may be based on the symptoms you describe and a physical exam. You may also need your blood pressure, heart rate, strength, refl exes, and/or sensitivity tested. Referral to a specialist will likely involve further tests.

If you have diabetes, it’s most likely that this will be the cause of neuropathy. However, there are other possible causes, such as infections, toxins, injuries, vitamin B12 defi ciency, and other autoimmune conditions. Long-term hypothyroidism (underactive thyroid), for example, can cause neuropathy.

HOW TO PREVENT AND TREAT NEUROPATHY

Keeping blood sugars as regulated as possible is all-important when it comes to protecting your nerves. Aim for HbA1c levels of <55 mmol/mol (but don’t beat yourself up if you don’t achieve this!) High cholesterol and high blood pressure are also known to make neuropathy worse and are important things to stabilise.

If you are diagnosed with neuropathy, focusing on diet and exercise and also looking at possible diff erent medication regimens will be important. Lowering your overall blood sugar levels can help slow the progress of neuropathy and sometimes even reduce or reverse symptoms. There are also a number of medicines that can help relieve neuropathy pain.

Other important things to do for neuropathy are: • make sure you get enough sleep • build time for rest into your life • talk with family, friends, a counsellor, or your healthcare professional if you are feeling down about it.

THE EXTRA BENEFITS OF EXERCISE

Exercise has many benefits for those suffering from neuropathy.

It lowers blood sugar levels and helps with weight loss, but there’s also good evidence that regular exercise can help reduce neuropathic pain as well as increase sensation in parts of the body that are numb and strengthen areas that are weakened.

The best routine includes a mix of strength and stability exercises (for example, tai-chi) and aerobic exercise (such as walking briskly).

WHAT IS NEUROPATHY AND AM I AT RISK?

1. Over long periods of time, high blood sugars can damage various nerves in the body in diff erent ways.

2. 'Sensory neuropathy' can cause numbness, pain, and/or tingling, often in the arms, legs, hands, and feet.

3. 'Motor neuropathy' can make muscles feel unusually weak. Hips, buttocks, and legs are often affected.

4. ‘Autonomic neuropathy’ is damage to nerves that control the body’s involuntary actions, e.g. digestion, breathing, and heart rate. It can be tricky to diagnose. Symptoms may include digestive problems, sudden blood pressure drops, rapid heartbeat, sexual dysfunction, hypoglycaemia unawareness, and others.

5. You should be screened for neuropathy at least once a year. Check your feet daily.

6. Aiming to keep blood glucose levels within a normal range is the best prevention and treatment for neuropathy. There is also increasing evidence that exercise helps control neuropathy in multiple ways.