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Note: All links within content go to MayoClinic.com

Coma. It's a scary word. But what does it have to do with diabetes? Plenty.

If you have diabetes, prolonged blood sugar extremes can cause you to lose consciousness. This is known as a diabetic coma. Both very high blood sugar (hyperglycemia) and very low blood sugar (hypoglycemia) can lead to a diabetic coma. Left untreated, a diabetic coma is a life-threatening condition.

But there's good news. The risk of a diabetic coma is small — and prevention is in your hands. Eating a healthy diet, taking your medication as prescribed and closely monitoring your blood sugar can go a long way toward preventing diabetes complications.

A diabetic coma doesn't strike out of the blue. You'll first experience signs and symptoms of high blood sugar or low blood sugar.

If your blood sugar is too high, you may experience:

• Increased thirst
• Frequent urination
• Dry mouth
• Nausea
• Vomiting
• Shortness of breath

If your blood sugar is too low, you may feel:

• Shaky or nervous
• Tired
• Sweaty
• Hungry
• Irritable
• Confused

Prolonged blood sugar extremes — blood sugar that's either too high or too low for too long — may cause various conditions, all of which can lead to a diabetic coma.

• Diabetic ketoacidosis. If your muscle cells become starved for energy, your body may respond by breaking down fat stores. This process forms harmful acids known as ketones. Left untreated, diabetic ketoacidosis can cause a coma. Diabetic ketoacidosis is most common in people who have type 1 diabetes, but it can also affect people who have type 2 diabetes or gestational diabetes.
• Diabetic hyperosmolar syndrome. If your blood sugar level tops 600 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 cause life-threatening dehydration and loss of consciousness. Diabetic hyperosmolar syndrome is most common in older adults with type 2 diabetes.
• Hypoglycemia. Your brain needs glucose to function. In severe cases, low blood sugar may cause you to pass out. Hypoglycemia is most common in people who take too much insulin or skip meals or snacks. Exercising too vigorously or drinking too much alcohol can have the same effect. How quickly your blood sugar drops influences the symptoms of hypoglycemia. For example, if it takes a few hours for your blood sugar to drop 50 mg/dL, the symptoms may be minimal. If your blood sugar drops the same amount in a few minutes, the symptoms will be more pronounced.

Anyone who has diabetes is at risk for a diabetic coma. Risk factors for the conditions that may lead to a diabetic coma vary, however.

For example, diabetic ketoacidosis is most common in people who have type 1 diabetes. 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.

A diabetic coma is a medical emergency. If you pass out, you'll need someone to call 911 for help.

When you're unconscious, prompt diagnosis is essential. The emergency medical team will do a physical exam and may ask those who are with you about your medical history.

You'll need various lab tests as well. Your blood sugar will be measured, and your urine may be tested for ketones. 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 cells and fluid in your blood. The doctor may also measure the amount of potassium in your blood.

Left untreated, a diabetic coma can lead to permanent brain damage. In some cases, an untreated diabetic coma can be fatal.

If your blood sugar is too high, you may be given 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.

If your blood sugar is too low and you're unable to eat, the hormone glucagon can be injected to quickly raise your blood sugar level.

Consciousness typically returns when blood sugar reaches a normal level.

The best way to prevent a diabetic coma is through day-to-day control of your diabetes. Keep these tips in mind:

• Follow your meal plan. Consistent snacks and meals can help you manage your blood sugar.
• Keep an eye on your blood sugar level. Frequent blood sugar tests can tell you whether you're keeping your glucose levels in your target range — and alert you to dangerous highs or lows.
• Take your medication as directed. If you have frequent episodes of high or low blood sugar, your doctor may adjust the dosage or timing of your medication. Your doctor may use a glycated hemoglobin test to determine how well you're managing your blood sugar.
• Educate your loved ones, friends and co-workers. Teach loved ones and other close contacts how to recognize early signs and symptoms of blood sugar extremes — and how to summon emergency help should you pass out. It also helps to occasionally review the education material you were given when you were first diagnosed with diabetes.
• Wear a medical ID bracelet or necklace. If you're unconscious, the ID can provide valuable information to your loved ones, co-workers and others — including emergency personnel.

Above all, keep your perspective. For most people who have diabetes, the risk of a diabetic coma is small. Take good care of yourself to help prevent diabetes complications.