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Note: All links within content go to MayoClinic.com

You have type 2 diabetes and you haven't been following your treatment plan. It's been a while since you've checked your blood sugar. You feel sluggish and weak and wonder if you're catching the flu. So you dig out your blood sugar testing supplies and discover that your blood sugar is sky high.

If your blood sugar level tops 600 milligrams per deciliter (mg/dL), the condition is known as diabetic hyperosmolar syndrome. When your blood sugar gets this high, your blood becomes thick and syrupy. The excess sugar passes from your blood into your urine, which triggers a filtering process that draws tremendous amounts of fluid from your body.

Left untreated, diabetic hyperosmolar syndrome can lead to life-threatening dehydration. Prompt medical care is essential.

Diabetic hyperosmolar syndrome may take days or even weeks to develop. Pay attention to early warning signs and symptoms:

• High blood sugar level
• Excessive thirst
• Dry, parched mouth
• Increased urination
• Warm, dry skin with no sweating
• Rapid pulse
• Shortness of breath with exertion
• Sleepiness
• Confusion

Most cases of diabetic hyperosmolar syndrome are caused by an underlying infection, such as pneumonia or a urinary tract infection. Undiagnosed diabetes or not following your diabetes treatment plan can have the same effect.

Other triggers may include:

• Certain medications, such as water pills (diuretics)
• Illness
• Substance abuse

Diabetic hyperosmolar syndrome is most common in older adults with type 2 diabetes — especially those who don't monitor their blood sugar or who don't know they have diabetes.

Consult your doctor if you experience any signs or symptoms of diabetic hyperosmolar syndrome. Seek emergency care if your blood sugar level is 600 mg/dL or higher.

You'll be diagnosed with diabetic hyperosmolar syndrome if your blood sugar level is 600 mg/dL or higher.

To evaluate how well your kidneys are working, the doctor may measure the amount of nitrogen or creatinine (a breakdown product of creatine, an important part of muscle) in your blood. Another blood test known as a hematocrit may be done to measure the proportion of red blood cells and fluid in your blood. The doctor may measure the amount of potassium in your blood as well.

Diabetic hyperosmolar syndrome can lead to convulsions or coma. Kidney damage is possible if the muscle fibers begin to break down. Blockages within the blood vessels may lead to a heart attack. Without prompt treatment, diabetic hyperosmolar syndrome can be fatal.

Emergency treatment can correct diabetic hyperosmolar syndrome within hours. Treatment typically begins with intravenous fluids to restore water to your tissues. You may need potassium, sodium or chlorine supplements to help your cells function correctly. When enough fluid has been replaced, short-acting insulin can help your tissues absorb glucose again. Any underlying infections will be treated as well.

To prevent diabetic hyperosmolar syndrome, keep an eye on your blood sugar level. Ask your doctor how often to check your blood sugar — and what to do if your blood sugar is too high. Sometimes high blood sugar can be treated at home by exercising, eating less or taking medication as directed. In other cases, you may need your doctor's help to safely lower your blood sugar.