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Type 2 Diabetes Complications

How to Prevent Short- and Long-term Complications

With type 2 diabetes (also called type 2 diabetes mellitus), if you don’t work hard to keep your blood glucose level under control, there are short- and long-term complications to contend with. However, by watching the amount and types of food you eat (your meal plan), exercising, and taking any necessary medications, you may be able to prevent these complications.

And even if you have some of the long-term, more serious complications discussed below when you’re first diagnosed, getting tight control of your blood glucose will help prevent the complications from becoming worse. (It is possible with type 2 diabetes to already have some of these complications when you’re first diagnosed. That’s because type 2 develops gradually, and you may not realize that you have high blood glucose for quite some time. Over time, high blood glucose can cause serious damage. You can learn more about that in this article on the symptoms of type 2 diabetes.) 

Short-term complications of type 2 diabetes are hypoglycemia (very low blood glucose) and hyperosmolar hyperglycemic nonketotic syndrome (HHNS), which is very high blood glucose.


Long-term complications of type 2 are diabetic retinopathy, kidney disease (nephropathy), diabetic neuropathy, and macrovascular problems.

Short-term Diabetes Complications

Hypoglycemia is low blood glucose (blood sugar). It is possible for your blood glucose to drop, especially if you’re taking insulin or a sulfonylurea drug (those make your body produce insulin throughout the day). With these medications, if you eat less than usual or were more active, your blood glucose may dip too much.
Other possible causes of hypoglycemia include certain medications (aspirin, for example, lowers the blood glucose level if you take a dose of more than 81mg) and too much alcohol (alcohol keeps the liver from releasing glucose).
The signs and symptoms of low blood glucose are easy to recognize:
  • Rapid heartbeat
  • Sweating
  • Whiteness of skin
  • Anxiety
  • Numbness in fingers, toes, and lips
  • Sleepiness
  • Confusion
  • Headaches
  • Slurred speech
Mild cases of hypoglycemia can be treated by drinking orange juice or eating a glucose tablet—those will quickly raise your blood glucose level.
If you have type 2 diabetes and you take insulin, you should always carry glucagon with you—should you become unresponsive or unconscious because of hypoglycemia, you will need a quick injection of glucagon. Glucagon is a hormone that starts a process in your body that raises your blood glucose level.
For more information about hypoglycemia and how to treat it, please read our article on hypoglycemia.
Hyperosmolar Hyperglycemic Nonketotic Syndrome
Hyperosmolar hyperglycemic nonketotic syndrome (HHNS) is very rare, but you should be aware of it and know how to handle it if it occurs. HHNS is when your blood glucose level goes way too high, and if you don’t treat it, it can cause death.
HHNS is most likely to occur when you’re sick, and elderly people are most likely to develop it. It starts when your blood glucose level starts to climb: when that happens, your body will try to get rid of all the excess glucose through frequent urination. That dehydrates your body, and you’ll become very thirsty.
Unfortunately, when you’re sick, you can’t always rehydrate your body as you should. You might have trouble keeping fluids down, for example. When you don’t rehydrate your body, the blood glucose level continues to climb, and it can eventually go so high that it will send you into a coma.
To avoid hyperosmolar hyperglycemic nonketotic syndrome, you should keep close watch on your blood glucose level when you’re sick (you should always pay attention to your blood glucose level, but pay special attention when you’re sick).
Talk to your healthcare professional about having a sick-day plan to follow.

Long-term Complications

By keeping your blood glucose level in a healthy range through meal planning, physical activity, and medications, you can avoid long-term complications of diabetes.
These complications develop over many years and they all relate to how blood glucose levels can affect blood vessels. Over time, high blood glucose can damage the body’s blood vessels, both tiny and large.
Damage to your tiny blood vessels causes microvascular complications; damage to your large vessels causes macrovascular complications.
Microvascular Complications: Eye, Kidney, and Nerve Disease
You have small blood vessels that can be damaged by consistently high blood glucose over time. Damaged blood vessels don’t deliver blood as well as they should, so that leads to other problems, specifically with the eyes, kidneys, and nerves.
  • Eyes: Blood glucose levels out of range for a long period of time can cause cataracts and/or retinopathy in the eyes. Both can cause loss of vision.

    To avoid eye problems associated with diabetes, keep your blood glucose within range and have yearly eye check-ups that include a dilated eye examination with an eye doctor to monitor your eye health.
  • Kidneys: If untreated, kidney disease (also called diabetic nephropathy) leads to impaired kidney function, dialysis and/or kidney transplant. Uncontrolled (or poorly controlled) diabetes can cause the kidneys to fail; they’ll be unable to clean the blood properly.

    To prevent diabetic nephropathy, you should be tested every year for microalbuminuria, which is a condition that’s an early sign of kidney problems. The test measures how much protein is in the urine. This test is easily done with a urine sample. When the kidneys begin to have problems, they start to release too much protein.  Medications can help prevent further damage, once microalbuminuria is diagnosed.
  • Nerves: Nerve damage caused by diabetes is also known as diabetic neuropathy. The tiny blood vessels “feed” your nerves, so if the blood vessels are damaged, then the nerves will eventually be damaged as well.

    In type 2 diabetes, some people will already show signs of nerve damage when they’re diagnosed. This is an instance where getting the blood glucose level under control can prevent further damage.

    There are various forms of diabetic neuropathy: peripheral, autonomic, proximal, and focal. Diabetic peripheral neuropathy is the most common form of nerve damage, and it most often affects the nerves going to the hands and feet.

    People who have had type 2 diabetes for a very long time and who haven't done well managing their blood glucose may lose sensation in their feet. They may also experience pain, weakness, or tingling.

    One serious complication of diabetic peripheral neuropathy in the feet is that people may not realize when they have a sore on their foot. The sore can become infected, the infection can spread, and left untreated, the foot may need to be amputated to keep the infection from spreading more. It is important to have regular foot exams done by a podiatrist, but you should also have your healthcare provider examine your feet every time you have an office visit.
Type 2 diabetes can also affect the large blood vessels, causing plaque to eventually build up and potentially leading to a heart attack, stroke or vessel blockage in the legs (peripheral vascular disease).
To prevent heart disease and stroke as a result of diabetes, you should manage your diabetes well, but you should also make heart-healthy choices in other areas of your life: don’t smoke, keep your blood pressure under control, and pay attention to your cholesterol.
It is important to have your cholesterol checked annually. Your doctor should check your blood pressure every office visit. Also at every office visit, the doctor should check the pulse in your feet to make sure there is proper circulation.
Type 2 diabetes comes with certain short- and long-term complications, but if you maintain good blood glucose control, you can avoid them.
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Type 2 Diabetes Prevention: Here's What You Can Do