Coma. It's a scary word. Scarier still if you have diabetes, because it's a very real risk.

"Both very high and very low blood sugar can lead to coma — an altered state of consciousness," says Maria Collazo-Clavell, M.D., an endocrinologist at Mayo Clinic, Rochester, Minn. "Left untreated, this condition can result in brain damage or even death."

How diabetic comas occur

If you have diabetes and your blood sugar gets too high (hyperglycemia) and stays too high, or your blood sugar gets too low (hypoglycemia) and stays too low, you can lose consciousness. This is referred to as a diabetic coma.

Comas arising from high blood sugar

Two types of conditions can occur when you don't receive prompt treatment for high blood sugar. These two conditions can lead to coma.

Diabetic ketoacidosis (DKA): If you have type 1 diabetes, you have a greater chance of developing DKA than do people with type 2 diabetes. Only in rare cases does DKA lead to diabetic coma. But when it does, it's often fatal.

Diabetic hyperosmolar syndrome (DHS): If you're older and have type 2 diabetes, you may develop DHS, a condition in which your blood sugar gets very high and you become dehydrated. In rare circumstances, DHS can lead to coma.

Comas arising from low blood sugar

Hypoglycemic coma is rarely fatal. In fact, most people survive with prompt treatment. But if low blood sugar isn't treated promptly, you could lose consciousness or develop seizures. And if you become unconscious and no one knows you have diabetes, you could experience permanent brain damage.

Prevention is the best approach

The best way to prevent diabetic coma is through day-to-day control of your medical condition. You can do this by following a proper diet, taking medication as prescribed and monitoring your blood sugar.

Here are more guidelines to help you avoid life-threatening consequences of blood sugar extremes.

Follow your meal plan. Once you've decided on a meal plan, remember that consistency is extremely important for managing your blood sugar. 

Monitor your blood sugar. Testing is crucial because it tells you whether you're keeping your glucose levels in the range you and your doctor have agreed on. You'll also know when to be alert to possible diabetic complications, such as DKA or DHS. 

Adjust your medication. If you have type 1 diabetes, work with your doctor or certified diabetes educator to find the insulin dosage that's right for you. If you have type 2 diabetes and your blood sugar levels are more often than not outside your target range, let your doctor know about it. He or she may choose to start or adjust your medications. Never stop your diabetes medication without your doctor's approval. 

Teach your friends, family and co-workers. Take a family member with you to your doctor's appointment so that he or she can learn about your condition and gain confidence to provide assistance when you need it. This may include learning how to recognize early symptoms of low blood sugar, how to respond to an insulin reaction and how to give you a glucagon injection if you become unconscious. Your friend or family member will be able to help you and may feel more comfortable in a diabetes emergency. 

Purchase an identification bracelet or necklace that identifies you as having diabetes. This can provide valuable information to your family, friends and co-workers, as well as emergency personnel.

Keep it in perspective

Diabetic coma is rare. But it's still a risk you have to prepare for.

Monitor your blood sugar as often as your health care team recommends. Do your best to follow your meal plan and medication regimen. Finally, teach your friends, family and co-workers how to respond if you lose consciousness.