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Diabetic coma is when someone is unconscious or unresponsive due to diabetes. The most important thing to know about diabetic coma is that it’s a medical emergency. If someone you know with diabetes is unresponsive, they may be in a diabetic coma. Call 911. 

It is important to know about diabetic coma if you or someone you know lives with diabetes. Individuals who lapse into a diabetic coma are still alive, but unable to recover on their own. 

Here’s what you need to know.

What Causes a Diabetic Coma?

There are two situations that can lead to a diabetic coma, both related to the amount of glucose (sugar) in your blood: dangerously high blood sugar (hyperglycemia) and dangerously low blood sugar (hypoglycemia).

  • Hyperglycemia means you have high blood sugar. When you live with type 1 diabetes, it means there is not enough insulin to process the glucose in your blood. For type 2 diabetes or prediabetes, your body is not making enough insulin or not using the insulin you have efficiently. High blood glucose over time can damage your kidneys, eyes, and other organs. Dangerously high blood glucose can lead to diabetic coma.
  • Hypoglycemia means you have low blood sugar. Hypoglycemia can happen when people living with diabetes have too much insulin present in the body. It also can happen when you are eating less overall or exercising a lot. Some medications for type 2 diabetes (specifically, sulfonylureas) can also increase the risk of hypoglycemia. Hypoglycemia is also known as insulin shock. Dangerously low blood glucose can lead to diabetic coma.

Signs and Symptoms

A diabetic coma is a reaction to very high or very low levels of glucose in your blood. There are signs and symptoms that can indicate you are at risk for diabetic coma.

If the level of glucose in your blood is too high (hyperglycemia) you may experience signs and symptoms similar to someone with undiagnosed diabetes. These signs and symptoms include:

  • Excessive thirst
  • Excessive fatigue
  • Frequent urination
  • Nausea or vomiting
  • Excessive hunger
  • Shortness of breath
  • Stomach pain
  • Rapid heartbeat
  • Weak pulse
  • Fruity-smelliing breath
  • Dry mouth
  • Sleepiness

If the level of glucose in your blood is too low (hypoglycemia) you may experience:

  • Shakiness
  • Anxiety or feelings of nervousness
  • Weakness
  • Excessive fatigue
  • Sweating
  • Excessive hunger
  • Nausea
  • Dizziness, light-headedness
  • Difficulty speaking
  • Confusion, disorientation

As you can see, hyper- and hypoglycemia have some of the same signs and symptoms. Most people know they have high or low blood sugar by the changes in their body, but some people living with diabetes have hypoglycemia unawareness. This means the person is completely unaware that their blood sugar is low either because they don’t have symptoms, or don’t recognize the symptoms. 

The best way to avoid hypoglycemia unawareness is to maintain healthy blood glucose levels through careful management of your diabetes. If you have hypoglycemia unawareness, your health care provider will guide you in how to manage this condition, including instructing you to check your blood sugar several times a day.  

If you are feeling one or more of the symptoms of hyper- or hypoglycemia, check your blood sugar immediately and follow your diabetes care plan based on the results of your test. 

If you have very high or low blood sugar and don’t start to feel better fairly quickly after treating the condition, or you feel worse, call 911 or your local emergency number. Educate your family members, friends, and coworkers on what to do if you become unconscious.

Conditions That Can Lead to Diabetic Coma

There are several serious conditions that left untreated can lead to diabetic coma. 

  • Ketoacidosis mostly occurs in people living with type 1 diabetes. It is much less common in people living with type 2 diabetes or gestational diabetes. Ketoacidosis happens when there is too little insulin in your body. Without insulin, your body begins burning fat for fuel, which raises the amount of ketones in your blood. The condition is accompanied by high blood glucose levels. It is a life-threatening condition because very large amounts of ketones in your blood and urine become toxic.
  • Hyperosmolarity happens when blood sugar becomes too high for a long period of time. Normally, when someone living with diabetes has high blood sugar, the kidneys try to eliminate the excess sugar through urine, which can lead to life threatening dehydration and coma. Eventually, your kidneys can’t keep up and your blood sugar rises even higher, sometimes more than 10 times the normal amount. Hyperosmolarity most often affects people living with type 2 diabetes, particularly older people who do not have their blood sugar well managed. Rarely, hyperosmolarity affects children and young adults who have type 1 or type 2 diabetes, and obesity is a factor in these situations.
  • Hypoglycemia means you have low blood sugar. It is caused by too much insulin or not enough carbohydrates in your body to cover the insulin. Heavy exercise without adequate preparation or drinking too much alcohol can also lead to hypoglycemia.

People living with type 1 diabetes have a greater risk of diabetic coma as a result of ketoacidosis or hypoglycemia because they always need insulin therapy and can experience broader fluctuation in blood glucose levels compared to people living with type 2 diabetes who are not on insulin therapy. People living with type 2 diabetes generally have a greater risk of diabetic coma as a result of hyperosmolarity.

Are You At Risk

Anyone who has diabetes is at risk of diabetic coma, but it most often occurs when something unusual is happening, or your diabetes is not well managed. Some risks are within your control more than others.  

Risk factors include:

  • Diabetes that is not well managed. If you don’t monitor your blood sugar and take action to manage your blood sugar level, you have an increased risk of diabetic coma. 

  • Skipping insulin doses or using too much. If you skip insulin doses or get too aggressive with insulin use, you will experience more extreme fluctuations in blood sugar levels.  

  • Alcohol consumption. Alcohol affects many parts of your body, including blood sugar and your general awareness, making it difficult to recognize when you have low blood sugar symptoms. Excessive alcohol will also cause your body to prioritize getting rid of the alcohol and slow down digestion of food, leaving you at risk of unexpected hypoglycemia if you injected insulin for your food. 

  • Using illegal substances. Many drugs can cause severely high blood sugar, including cocaine and ecstasy, and have been linked to diabetic coma. 

  • Illness, surgery, or trauma. These factors are outside your control. Be extra vigilant checking your blood sugar when you are sick, have an injury, or require surgery. In some cases, these conditions can cause higher blood sugar levels, requiring an increase of insulin to avoid ketoacidosis (mostly for people living with type 1 diabetes). Some medical conditions like heart failure can increase your risk of hyperosmolarity. 

  • Problems with insulin delivery. This risk factor usually occurs when an insulin pump is used. If you use an insulin pump, check your blood sugar often to make sure the pump is working properly. 

Have a Plan

You can best manage the risk factors for diabetic coma if you have solid control of blood sugar through careful diabetes management. Eat a healthy diet with snacks and meals to help you manage your blood sugar. Test your blood sugar as directed by your healthcare provider, or even more often, and take medication as needed. If your blood sugar is very high (300 mg/dL or higher), test your urine for ketones. If you often have high or low blood sugar, consult your healthcare provider as you may need to adjust your diabetes care plan. You may benefit from a continuous glucose monitor if you have trouble maintaining your blood sugar and can get insurance coverage. A continuous glucose monitor is a device that uses a sensor inserted under your skin to monitor blood glucose. It alerts you if your blood sugar is too high or too low. 

If you are sick and unable to eat, your blood sugar can drop. Discuss strategies with your health care provider to best maintain blood sugar while you are sick. It’s also a good idea to make sure you always have several days of diabetes supplies on hand in case of an emergency.  

If you take insulin for your diabetes, have a glucagon kit, glucose tablets, glucose powder, or another source of fast acting sugar (like orange juice) available in case you experience low blood sugar. 

Glucagon kits are prescribed by your doctor and include injectable glucagon, a hormone that increases blood sugar levels. It is only used in situations where you cannot eat or are unconscious. Because of this, it is most often given by someone else, so make sure your family, friends and coworkers know why, when, and how to administer the injection in case you are unable to do it yourself.  

Take extra caution if you drink alcohol since it can have unpredictable effects on your blood glucose. If you choose to drink, have a snack or meal at the same time. 

Lastly, educate your family, friends and coworkers about extremes in blood sugar levels, how to recognize the signs and symptoms of blood sugar extremes, and what to do if this occurs. Wear a medical identification bracelet that lets others know you have diabetes in case you are unable to communicate.  

In summary, diabetic coma is a serious condition that requires immediate medical care. The good news is you can learn to recognize the signs and symptoms, but more importantly, effective management of your diabetes will greatly reduce the risk of diabetic coma. 


Diabetic Coma: Causes, Risk Factors, Treatment & Prevention | Cleveland Clinic

When You Don't Know You're Low - Hypoglycemia Unawareness| diaTribe 

Diabetic Coma |

Diabetic Coma: Symptoms and causes | Mayo Clinic 

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