Diabetes and the nervous system: nerve damage, stroke, neurologists
What UK health bodies say about diabetic nerve damage, foot checks, stroke risk and warning signs, and which specialists may be involved when symptoms are complex.
Diabetes is usually discussed in terms of glucose and insulin, but over many years it can also affect the nerves and the blood vessels that supply the brain. This page summarises what the NHS, NICE and Diabetes UK say about nerve damage and stroke, and who may be involved in care. It is general information rather than personal advice, and anyone with symptoms should contact their own GP or diabetes team.
How high glucose can damage nerves
Diabetes UK describes diabetic neuropathy as nerve damage caused by diabetes, and says it can affect nerves in the feet, organs and muscles. Over time, high glucose levels can damage the small blood vessels that supply the nerves, which stops nutrients reaching them, so the nerve fibres can become damaged. The NHS adds that diabetes, both type 1 and type 2, is the most common cause of peripheral neuropathy in the UK.
The NHS describes three groups of nerves in the peripheral nervous system: sensory nerves, which carry sensations such as pain and touch; motor nerves, which control muscles; and autonomic nerves, which regulate automatic functions such as blood pressure and bladder function. Diabetes UK lists four main types (peripheral, sensory, autonomic and motor), and a person could have one or any combination. In outline, autonomic neuropathy is damage to nerves that carry information to the organs and glands, and Diabetes UK gives examples such as slow stomach emptying, bladder problems, irregular heartbeats, problems with sweating and dizziness on standing up. The glossary entry on neuropathy gives a short definition.
Common symptoms, and why to tell the diabetes team
According to Diabetes UK, more common symptoms include numbness, tingling or burning, pain, weakness, loss of reflexes, and changes to body functions such as constipation, diarrhoea or bladder leaking. The NHS lists early symptoms of peripheral neuropathy as pain, tingling or loss of sensation in the feet, loss of balance or weakness, and a cut or ulcer on the foot that is not getting better, and says to see a GP if they appear. It adds that the sooner peripheral neuropathy is diagnosed, the better the chance of limiting the damage.
Diabetes UK points out that doctors and nurses screen for neuropathy at the annual review, but that not all types are screened for, so new or worsening symptoms should be raised with a GP. Treatment depends on the type of nerve affected. The same charity says that keeping glucose, cholesterol and blood pressure within target can help improve symptoms and stop damage getting worse, though in some people the damage is permanent. Treatment decisions belong with the person's own team.
Foot checks
Loss of feeling matters because minor injuries can go unnoticed. Diabetes UK explains that if ignored, such injuries can develop into infections or ulcers, and advises checking feet every day and having them checked by a healthcare professional once a year.
NICE guideline NG19 covers preventing and managing diabetic foot problems. For adults it recommends assessing the risk of a diabetic foot problem when diabetes is diagnosed and at least annually afterwards, and its assessment includes neuropathy, using a 10 g monofilament as part of a foot sensory examination. For people at low risk, the foot assessment continues at the annual diabetes review; people at moderate or high risk are referred to a foot protection service.
How diabetes raises stroke risk
Diabetes UK explains that a stroke happens when the blood supply to part of the brain is cut off. If glucose levels stay too high over time they can damage blood vessels, making them harder and more likely to become blocked, and a clot that travels to the brain causes a stroke. High cholesterol and high blood pressure can also damage vessels, and living with diabetes can increase the chance of both. The charity estimates that diabetes is a cause in over 1,010 strokes every week in the UK. The NHS includes diabetes in its list of conditions that increase the risk of stroke, alongside high blood pressure, atrial fibrillation and high cholesterol.
On lowering the risk, Diabetes UK says to have HbA1c, blood pressure and cholesterol measured at least once a year at the annual review and to work with the healthcare team to keep them within target. It also lists stopping smoking, drinking less alcohol, a balanced diet, being as active as possible, and taking prescribed medicines as directed. For people who have already had a stroke or mini-stroke, the NHS lists similar steps to lower the risk of another: quitting smoking, a balanced diet, exercise and cutting down on alcohol. Advice about a particular person's targets or medicines comes from their own team.
Stroke warning signs and calling 999
The NHS describes the main symptoms of a stroke, which can happen suddenly, as face weakness (one side may droop), arm weakness (difficulty lifting both arms because of weakness or numbness in one) and speech problems (slurred words or confusion). It uses the word FAST: face, arms, speech and time to call 999. Other signs include weakness or numbness down one side of the body, blurred vision, confusion, dizziness and a severe headache.
Sudden weakness, trouble with speech or a drooping face is an emergency, and the NHS says to call 999. It advises calling 999 if you think you are having, or have had, a stroke, or if you have had signs of a stroke within the last 24 hours even if they have stopped. It also says not to drive yourself to A&E, because the person on the 999 line will give advice about what to do.
Who is involved: GPs, diabetes teams and neurologists
For most people the first contact is the GP or the diabetes team. The NHS says a GP will ask about symptoms, may arrange tests to find the cause, and that a person may be referred to hospital to see a neurologist, a specialist in health problems affecting the nervous system. Diabetes UK says the healthcare team should tell a person which areas are affected and advise on symptoms.
Neurology is a broad field, and some neurology practices list interventional neurology among their services. A 2012 editorial in the journal Interventional Neurology describes it as a subspecialty of neurology in which minimally invasive procedures are performed under radiologic or ultrasonographic guidance, including endovascular work on cerebrovascular diseases. The NHS stroke treatment page lists surgery to remove a blood clot (thrombectomy) among treatments that may be given in the first 24 hours after a stroke, but for a suspected stroke the route the NHS gives is the 999 call, not an appointment.
After a stroke, the NHS says a hospital team of doctors, specialists and therapists helps start recovery. Which specialist is involved depends on the person's situation, and the hospital team decides.
Where pump users fit in
People who use an insulin pump are not treated as a separate group in any of these sources: the annual review, foot assessment and stroke-risk checks are described for people with diabetes in general. Terms used on this page are explained in the glossary, and anyone using a pump should raise anything unusual, such as new numbness, pain or dizziness, with their diabetes team in the same way.
In short
Years of raised glucose can damage nerves and blood vessels, which is why the NHS, NICE and Diabetes UK describe regular foot checks, annual reviews and attention to blood pressure and cholesterol. New numbness, tingling or pain should be raised with a GP or the diabetes team, and a neurologist may be involved when symptoms are complex. Sudden weakness, speech trouble or a drooping face means calling 999 straight away.