Diabetic Coma and Type 2 Diabetes

Medically Reviewed by Michael Dansinger, MD on August 14, 2022

A diabetic coma could happen when your blood sugar gets too high -- 600 milligrams per deciliter (mg/dL) or more -- causing you to become very dehydrated.

It usually affects people with type 2 diabetes that isn’t well-controlled. It’s common among those who are elderly, chronically ill, and disabled. Doctors aren’t sure why, but they think these people may not realize they’re thirsty or may not be able to get enough to drink.

This is a serious condition, and if it isn’t spotted soon and treated quickly, it could be fatal. Knowing the symptoms can help you stay safe.

What Are the Warning Signs?

If you have diabetes and you’ve had a heavy thirst and gone to the bathroom more often than usual for a few weeks, check with your doctor -- especially if your blood sugar isn’t well-controlled. As your body loses more and more water, you may notice:

  • High fever
  • Weakness
  • Drowsiness
  • Altered mental state
  • Headache
  • Restlessness
  • Inability to speak
  • Visual problems
  • Hallucinations
  • Paralysis

What Causes Diabetic Coma?

These factors may lead to dehydration and coma:

How Is It Treated?

Once your doctor spots the early signs, they may send you to the hospital. You’ll get an IV to replace lost fluids and electrolytes such as potassium. And you’ll get insulin or other medication to control your blood sugar. The coma can lead to death if left untreated.

Can It Be Prevented?

Take these simple steps to help protect yourself:

  • Check your blood sugar regularly, as your doctor recommends.
  • Know your target blood sugar ranges and what to do if the readings are too high.
  • Plan how often to check your blood sugar when you’re sick.
  • Take extra care of yourself if you’re ill.

Show Sources


American Diabetes Association: "Living With Diabetes."

MedlinePlus: "Diabetic hyperglycemic hyperosmolar syndrome."

Brenner Z.  AACN Clin Issues,  2006 Jan-Mar. 

Stentz, F. Diabetes.

Mayo Clinic: "Diabetic hyperosmolar syndrome."


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