How Diabetes Affects the Body: Eyes, Heart, Kidneys, Nerves and Mouth

Diabetes, when poorly-controlled, results in multiple complications. Diabetes is a leading cause of kidney failure, blindness, limb amputation, heart attack and stroke.

Diabetes complications can be broadly divided into those affecting the small blood vessels (microvascular) and those affecting the large blood vessels (macrovascular).

Diabetic eye disease (diabetic retinopathy) results from reduced blood flow to the light-sensing nerve layer of the eye (retina). Over time, there is formation of fragile and leaky new blood vessels and nerve layer swelling. These changes can progress to blindness if not identified early and treated.

Diabetes affects the peripheral and central retina in different ways:
• Non-proliferative diabetic retinopathy, also known as background diabetic retinopathy, is the early stage of diabetic retinopathy and occurs when the small retinal blood vessels become affected and start to leak and bleed. At this stage, vision is usually no affected.

• Proliferative diabetic retinopathy is associated with a high risk permanent loss of vision. There is growth of abnormal new vessels in the retina. These abnormal new vessels can rupture, causing significant bleeding that will lead to loss of visions.
Progressively, the scar tissues that form can cause retinal detachment. The abnormal blood vessels can grown on the iris and block the outflow of fluid from the eye. Neovascular glaucoma can occur, with risk of optic nerve damage and blindness.

Proliferative diabetic retinopathy

What puts me at risk of diabetic retinopathy?
All individuals with diabetes are at risk of developing diabetic retinopathy. After 20 years, most people will develop this complication to some degree. Those who have poorly-controlled diabetes are at higher risk of developing diabetic retinopathy earlier and at more severe stages.

What can i do to protect my eyes?
Reduce your risk of diabetic retinopathy by:
• Keeping your blood glucose levels in check

• Treating and keeping other medical conditions such as high blood pressure, high cholesterol and heart disease under control

• Quitting smoking and exercising regularly

Although you cannot completely prevent diabetic retinopathy, vision loss can be prevented with early detection.

Diabetic retinopathy often has no warning signs, hence it is important to get a comprehensive dilated eye examination or retinal fundus photography annually even if you have no eye symptoms.

Treatment for diabetic retinopathy
In most cases, laser surgery can prevent significant vision loss associated with diabetic retinopathy.

Laser photocoagulation can be performed to seal or destroy growing or leaking blood vessels in the retina:
• Panretinal photocoagulation (PRP) - to treat peripheral retina to prevent or stop the growth of abnormal new vessels.

• Focal laser - to treat the macular oedema to reduce swelling.

In general, each eye requires 2-3 sessions for a PRP to be completed. You will be expected to go for regular treatments over a period of 6-12 months before diabetic retinopathy is controlled adequately.

In patients with loss of central vision due to diabetic macular oedema, intravitreal injections of medication into the centre of the eye can reduce the macular swelling and improve vision.

Medications which are injected into the eye for diabetic macular oedema include anti-vascular endothelial growth factor (VEGF) drugs such as Avastin, Lucentis and Eylea, as well as steroids.

Often, multiple injections at intervals of 1 month or longer are required to achieve resolution of the swelling. Repeated injections at longer intervals may also be required to maintain visual improvement.

In some people with diabetic retinopathy, the abnormal blood vessels in the retina may also result in massive bleeding into the centre of the eye (vitreous humour), causing sudden severe loss of vision. A surgical procedure called vitrectomy can be used to remove the blood that has leaked into this part of the eye.

Heart and blood vessel (cardiovascular) diseases arise from poorly-controlled diabetes associated with high blood pressure and other risk factors, leading to heart attacks, strokes and amputation of limbs.

What can I do to protect my heart and blood vessels?
The following measures can help to reduce your risk of these complications:
• Exercise regularly (at least 150 minutes per week). Consult your doctor before starting a new exercise regimen.

• Quit smoking.

• Keep your glucose and blood pressure levels in the target range with lifestyle measures and medications.

• Take the medications prescribed by your doctor regularly. These may include aspirin, angiotensin converting enzyme inhibitors / angiotensin-receptor blockers (ACEI/ARB), and cholesterol lowering and blood pressure lowering medications.

• Some type 2 benefits medications have additional benefts on lowering your cardiovascular risk. Speak to your healthcare team about this.

People with diabetes have a greater risk of developing gum (periodontal) disease, tooth decay, fungal infection and other problems with oral (mouth) health.

Serious gum disease may also have the potential to affect blood glucose control and contribute to the progression of diabetes. It is therefore important for you to start and maintain a regular dental care routine.

How can I help prevent dental problems associated with diabetes?
You can make sure your mouth stays healthy and pain-free with these simple steps: 

Control your blood glucose levels
• Those with poorly-controlled blood glucose levels are more likely to develop gum disease and can lose more teeth than someone whose diabetes is well-controlled. Good blood glucose control can also help prevent or relieve dry mouth caused by diabetes.

Brush and floss regularly
• Use a soft-bristled tooth brush and replace it every 3 months.

• Brush for at least 3 minutes with fluoride toothpaste.

• Brush at least 2 times a day, after each meal if you can.

• Floss at least once a day.

Visit a dental professional
• Have your teeth checked by the dentist at least once a year.

• Inform the dentist you have diabetes, how your glucose control is, and the medications you are taking.

Alert your dentist or doctor if you notice any of the following:
• Bleeding, red or sore gums.

• Gums that are pulling away from teeth.

• Bad breath for a long period of time.

• Loose or separating adult teeth.

• A change in the way you bite.

• Any mouth pain.

Diabetic kidney disease (diabetic nephropathy) starts with protein (albumin) leak in the urine. At this stage, the patient with diabetes may not have any symptoms due to kidney disease. However, this early stage can be identified easily by doing a urine test.

Protein leak in the urine is the earliest sign of diabetic kidney disease and if left untreated, it can progress to kidney failure, eventually requiring dialysis.

What can I do to protect my kidneys?
Urinary protein leak improves with improvement in glucose and blood pressure. Certain blood pressure medications (ACEI/ARB) are also used to reduce urinary protein leak and retard further progression of diabetic kidney disease. If you are found to have urinary protein leak, these medications will be recommended even if your blood pressure is normal.

Some type 2 diabetes medications have additional benefits on protecting your kidneys. Speak to your healthcare team about this.

Diabetic nerve disease (diabetic neuropathy) most commonly affects the nerves of the upper and lower limbs. It can also affect nerves that control the eye and nerves of the face and head.

The most common symptoms experienced are a tingling, burning, and pricking sensation or numbness of the hands and feet.

If diabetes is poorly-controlled, the nerve disease gets worse and spreads to involve larger regions of the limbs.

Many patients are unaware of the irreduced ability to sense pain and touch. This puts them at risk of injuries to their limbs that go unnoticed (e.g. burns from walking barefoot on a hot surface, injury from stepping on a sharp object). These wounds are exposed to contamination from the environment and get infected. If not identified early and treated, the infection may spread deeper to involve the muscle and bone, eventually requiring amputations.

Diabetes and high blood sugar levels can affect the feet in various ways. Over time, it can cause damage to:
1. Blood vessels, causing peripheral vascular disease

2. Nerves, causing neuropathy

Together, these conditions increase the risk of foot wounds.

What can I do to protect my feet?

It is important to check your feet regularly for any injuries, wounds, blisters and skin thickening (callus). You should also attend an annual diabetic foot screening with your healthcare provider to check for any reduced sensation and blood flow to your feet.

Early stages of complications from diabetes can occur without your knowledge. That is why it is important to get yourself screened regularly for diabetes-related complications.

Annual diabetes complication screening is recommended for all individuals with diabetes. 

The purpose of this screening is to detect any potential complication sat an early stage, and intervene with lifestyle changes or medications to reduce the risk of progression.

 
Ref: F26