Diabetic hyperosmolar (hi-pur-oz-MOE-lur) syndrome is a serious condition caused by extremely high blood sugar levels. The condition most commonly occurs in people with type 2 diabetes. It's often triggered by illness or infection.

In diabetic hyperosmolar syndrome, your body tries to rid itself of the excess blood sugar by passing it into your urine. Left untreated, diabetic hyperosmolar syndrome can lead to life-threatening dehydration. Prompt medical care is essential.

Diabetic hyperosmolar syndrome can take days or weeks to develop. Possible signs and symptoms include:

• Blood sugar level of 600 milligrams per deciliter (mg/dL) or 33.3 millimoles per liter (mmol/L) or higher
• Excessive thirst
• Dry mouth
• Increased urination
• Warm, dry skin
• Fever
• Drowsiness, confusion
• Hallucinations
• Vision loss
• Convulsions
• Coma

When to see a doctor

Consult your doctor if your blood sugar is persistently higher than the target range your doctor recommends or if you have signs or symptoms of diabetic hyperosmolar syndrome, such as those listed above.

Seek emergency care if:

• Your blood sugar level is 400 mg/dL (22.2 mmol/L) or higher and doesn't improve despite following your doctor's instructions for treatment. Don't wait until your blood sugar is high enough to cause diabetic hyperosmolar syndrome.
• You have confusion, vision changes or other signs of dehydration.

Diabetic hyperosmolar syndrome may be triggered by:

• Illness or infection
• Not following a diabetes treatment plan or having an inadequate treatment plan
• Certain medications, such as water pills (diuretics)

Sometimes undiagnosed diabetes results in diabetic hyperosmolar syndrome.

Your risk of developing diabetic hyperosmolar syndrome might be higher if you:

• Have type 2 diabetes. If you don't monitor your blood sugar or you don't yet know you have type 2 diabetes, your risk is higher.
• Are older than age 65.
• Have another chronic health condition, such as heart disease or kidney disease.
• Have an infection, such as pneumonia, a urinary tract infection or a virus, which causes blood sugar levels to rise.
• Take certain medications. Some drugs — such as corticosteroids (prednisone), diuretics (hydrochlorothiazide and chlorthalidone) and certain inhalers such as terbutaline.

Diabetic hyperosmolar syndrome can lead to:

• Seizures
• Heart attack
• Stroke
• Coma

Without prompt treatment, diabetic hyperosmolar syndrome can be fatal.

Good daily control of your diabetes can help you prevent diabetic hyperosmolar syndrome.

• Know the symptoms of high blood sugar. Be alert for the warning symptoms of high blood sugar, as well as the situations that put you at risk of developing hyperosmolar syndrome, such as illness or infections.
• Monitor your blood sugar level. Monitoring will help you stay in your target range and alert you to dangerous highs. Ask your doctor how often you should test your blood sugar. Monitor more often when you're sick.
• When you're sick, drink plenty of liquids. Drink a glass of nonalcoholic, caffeine-free beverage hourly until you can ask your doctor for advice.
• Follow your diabetes management plan. Eat healthy meals, take medications as directed and exercise regularly.
• Educate your loved ones, friends and co-workers. Teach people you spend time with to recognize early signs and symptoms of blood sugar extremes — and to get emergency help if you pass out.
• Wear a medical ID bracelet or necklace. If you're unconscious, the ID can provide valuable information to others, including emergency workers.
• Stay current on vaccinations. Get an annual flu shot and ask your doctor if you need the pneumococcal vaccine, which protects against some forms of pneumonia.

For diabetic hyperosmolar syndrome, prompt diagnosis is critical. The emergency medical team will do a physical and mental status exam and may ask those who are with you about your medical history.

Tests

You'll likely have several lab tests, including blood and urine tests to measure your blood sugar level and kidney function and to detect infection, among other conditions. Your doctor may take other samples to test in a lab if your doctor thinks you may have an infection. You may also have an electrocardiogram to check for certain heart problems.

Emergency treatment can correct diabetic hyperosmolar syndrome within hours. Treatment typically includes:

• Fluids given through a vein (intravenously) to treat dehydration
• Insulin given through a vein (intravenously) to lower your blood sugar levels
• Potassium and sometimes sodium phosphate replacement given through a vein (intravenously) to help your cells function correctly

If you have an infection or an underlying health condition, such as congestive heart failure or kidney disease, these conditions will be treated as well.

Diabetic hyperosmolar syndrome is a medical emergency that you won't have time to prepare for.

If you have symptoms of high blood sugar, such as extreme thirst and excessive urination, for a few days, check your blood sugar level and call your doctor for advice. If you feel the symptoms of extreme high blood sugar, call 911 or your local emergency number. Don't try to drive yourself to the hospital.

If you're with someone who has diabetes and is acting confused, has one-sided weakness or has passed out, call for medical help right away.

After you've received treatment and are feeling better, some questions you might want to ask your doctor include:

• How can I better control my diabetes?
• What range does my blood sugar need to be in?
• Do I need to see a specialist?
• I have these other health problems. How can I manage them together?
• What dietary changes do I need to follow?
• Should I see a dietitian?
• Does eating a meal with a lot of sugar bring on this syndrome?
• Do I need to drink more fluids?
• Can diabetic hyperosmolar syndrome happen again?