Extreme high blood sugar can lead to two life-threatening conditions:
Hyperosmolar Hyperglycemic Nonketotic Syndrome (HHNS)
This is a life-threatening condition most often seen in elderly people. HHNS can happen to people with either type 1 or type 2 diabetes, but it occurs more often in people with type 2 diabetes. HHNS is usually caused by an illness, infection, or by missing doses of your medicine over a period of time.
In HHNS, blood sugar levels rise, and the body tries to get rid of the excess sugar by passing it into your urine. You will make a lot of urine at first. Later you may not have to go to the bathroom as often, and your urine becomes very dark. This might make you very thirsty. It is important even if you are not thirsty, to drink liquids. This will help keep you from getting dehydrated.
If HHNS continues, the severe dehydration will lead to seizures, coma and eventually death. HHNS may take days or even weeks to develop. Know the warning signs of HHNS:
Very high blood sugar level (over 600 mg/dL)
Extreme thirst (although this may gradually disappear)
Warm, dry skin that does not sweat
Sleepiness or confusion
Loss of vision
Hallucinations (seeing or hearing things that are not there)
Weakness on one side of the body
Test your blood sugar if symptoms appear. Drink fluids if you can. Call your doctor right away.
The best way to avoid HHNS is to check your blood sugar regularly. You can also work with your doctor to develop a sick-day plan, so that you can reduce the risk of HHNS caused by sickness.
Ketoacidosis is a serious condition that can lead to diabetic coma or even death. Ketoacidosis may happen to people with type 1 diabetes. It occurs rarely in people with type 2 diabetes.
Ketoacidosis means dangerously high levels of ketones. Ketones are acids that build up in the blood. They appear in the urine when your body doesn’t have enough insulin. They are a warning sign that your diabetes is out of control or that you are getting sick.
Treatment for ketoacidosis usually takes place in the hospital. But you can help prevent ketoacidosis by learning the warning signs and checking your urine for ketones and blood sugar regularly. Ask your doctor when and how you should test for ketones.
Many experts advise checking your urine for ketones when your blood glucose is more than 240 mg/dL. When you are ill (when you have a cold or the flu, for example), check for ketones every four to six hours. And, check every four to six hours when your blood glucose is more than 240 mg/dL.
Also, check for ketones when you have any symptoms of ketoacidosis. Some of the first symptoms are:
Thirst or a very dry mouth
High blood glucose (sugar) levels
High levels of ketones in the urine
Next, some other symptoms may appear:
Constantly feeling tired
Dry or flushed skin
Nausea, vomiting, or abdominal pain (Vomiting can be caused by many illnesses, not just ketoacidosis. If vomiting continues for more than two hours, contact your healthcare provider.)
A hard time breathing (short, deep breaths)
Fruity odor on breath
A hard time paying attention, or confusion
If you have these symptoms, test your blood sugar and your urine ketones.
Call your doctor at once if:
Your urine tests show large ketones
Your urine tests show large ketones and your blood glucose level is high
You have vomited more than twice in four hours and your urine tests show high ketones