diabetic coma

What is a diabetic coma

A diabetic coma is a life-threatening diabetes complication that causes unconsciousness. If you have diabetes, dangerously high blood sugar (hyperglycemia) or dangerously low blood sugar (hypoglycemia) can lead to a diabetic coma.

If you lapse into a diabetic coma, you’re alive — but you can’t be awaken or respond purposefully to sights, sounds or other types of stimulation.

Left untreated, a diabetic coma can lead to:

  • Permanent brain damage
  • Death

The prospect of a diabetic coma is scary, but fortunately you can take steps to help prevent it. Start by following your diabetes treatment plan.

A diabetic coma is a medical emergency. If you feel extreme high or low blood sugar signs or symptoms and think you might pass out, call your local emergency number. If you’re with someone with diabetes who has passed out, call for emergency help, and be sure to let the emergency personnel know that the unconscious person has diabetes.

Diabetic coma causes

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.

The three most common causes of diabetic coma in people with diabetes are:

  1. Severe hypoglycemia
  2. Diabetic ketoacidosis
  3. Hyperglycaemic hyperosmolar syndrome

Severe hypoglycemia

Severe hypoglycemia, as defined by the American Diabetes Association, denotes severe cognitive impairment requiring external assistance for recovery. The International Study Group 1) suggests that a level of 54 mg/dl (<3.0 mmol/l) be defined as denoting serious clinically important hypoglycemia, whether that level is associated with symptoms or not of hypoglycemia.

Hypoglycemia is commonly associated with the treatment of diabetes. However, a variety of conditions, many of them rare, can cause low blood sugar in people without diabetes. Like fever, hypoglycemia isn’t a disease itself — it’s an indicator of a health problem.

The only sure way to know whether you are experiencing hypoglycemia is to check your blood glucose, if possible. If you are experiencing symptoms and you are unable to check your blood glucose for any reason, treat the hypoglycemia. Severe hypoglycemia has the potential to cause accidents, injuries, coma, and death.

Immediate treatment of hypoglycemia involves quick steps to get your blood sugar level back into a normal range — about 70 to 110 mg/dl, or mg/dL (3.9 to 6.1 millimoles per liter, or mmol/L) — either with high-sugar foods or medications. Long-term treatment requires identifying and treating the underlying cause of hypoglycemia.

What causes hypoglycemia (low blood sugar)

Hypoglycemia occurs when your blood sugar (glucose) level falls too low, below 70 mg/dl (3.9 mmol/l). There are several reasons why this may happen, the most common being a side effect of drugs used for the treatment of diabetes.

If you have diabetes, the effects of insulin on your body are drastically diminished, either because your pancreas doesn’t produce enough of it (type 1 diabetes) or because your cells are less responsive to it (type 2 diabetes). As a result, glucose tends to build up in your bloodstream and may reach dangerously high levels. To correct this problem, you likely take insulin or other drugs designed to lower blood sugar levels.

  • If you take insulin or some other diabetes medicines, your blood glucose level can drop too low.

If you take too much insulin relative to the amount of glucose in your bloodstream, it can cause your blood sugar level to drop too low, resulting in hypoglycemia. Hypoglycemia may also result if, after taking your diabetes medication, you don’t eat as much as usual (ingesting less glucose) or you exercise more (using up more glucose) than you normally would. Two types of diabetes pills can cause hypoglycemia: sulfonylureas and meglitinides – medicines that help your body make more insulin. To prevent this from happening, it’s likely that your doctor will work with you to find the optimum dosage that fits your regular eating and activity habits.

  • Other people may start to have symptoms of hypoglycemia when their blood glucose levels are higher than 70 mg/dl (3.9 mmol/l). This can happen when your blood glucose levels are very high and start to go down quickly. If this is happening, discuss treatment with your health care provider.

The following factors can make hypoglycemia more likely:

  • Not eating enough carbohydrates (carbs)

When you eat foods containing carbohydrates, your digestive system breaks down the sugars and starches into glucose. Glucose then enters your bloodstream and raises your blood glucose level. If you don’t eat enough carbohydrates to match your medication, your blood glucose could drop too low.

  • Skipping or delaying a meal

If you skip or delay a meal, your blood glucose could drop too low. Hypoglycemia also can occur when you are asleep and haven’t eaten for several hours.

  • Increasing physical activity

Increasing your physical activity level beyond your normal routine can lower your blood glucose level for up to 24 hours after the activity.

  • Drinking too much alcohol without enough food

Alcohol makes it harder for your body to keep your blood glucose level steady, especially if you haven’t eaten in a while. The effects of alcohol can also keep you from feeling the symptoms of hypoglycemia, which may lead to severe hypoglycemia.

  • Being sick

When you’re sick, you may not be able to eat as much or keep food down, which can cause low blood glucose. Learn more about taking care of your diabetes when you’re sick.

Possible causes, without diabetes

Hypoglycemia in people without diabetes is much less common. Causes may include the following:

  • Medications. Taking someone else’s oral diabetes medication accidentally is a possible cause of hypoglycemia. Other medications may cause hypoglycemia, especially in children or in people with kidney failure. One example is quinine (Qualaquin), which is used to treat malaria.
  • Excessive alcohol consumption. Drinking heavily without eating can block your liver from releasing stored glucose into your bloodstream, causing hypoglycemia.
  • Some critical illnesses. Severe illnesses of the liver, such as severe hepatitis, can cause hypoglycemia. Disorders of the kidney, which can keep your body from properly excreting medications, can affect glucose levels due to a buildup of those medications. Long-term starvation, as may occur in the eating disorder anorexia nervosa, can result in the depletion of substances your body needs in gluconeogenesis, causing hypoglycemia.
  • Insulin overproduction. A rare tumor of the pancreas (insulinoma) may cause overproduction of insulin, resulting in hypoglycemia. Other tumors may result in excessive production of insulin-like substances. Enlargement of beta cells of the pancreas that produce insulin (nesidioblastosis) may result in excessive insulin release, causing hypoglycemia.
  • Hormone deficiencies. Certain disorders of the adrenal glands and the pituitary gland can result in a deficiency of key hormones that regulate glucose production. Children with these disorders are more prone to hypoglycemia than are adults.

Hypoglycemia after meals

Hypoglycemia usually occurs when you haven’t eaten (when you’re in a fasting state), but that’s not always the case. Sometimes hypoglycemia occurs after meals because the body produces more insulin than is needed.

This type of hypoglycemia, called reactive or postprandial hypoglycemia, may occur in people who have had stomach surgery. It may also occur in people who haven’t had this surgery.

Signs and symptoms of hypoglycemia

Hypoglycemic symptoms are important clues that you have low blood glucose. Each person’s reaction to hypoglycemia is different, so it’s important that you learn your own signs and symptoms when your blood glucose is low.

Similar to the way a car needs gas to run, your body and brain need a constant supply of sugar (glucose) to function properly. If glucose levels become too low, as occurs with hypoglycemia, it can happen quickly and cause these signs and symptoms:

  • Shakiness
  • Nervousness or anxiety
  • Heart palpitations
  • Fatigue
  • Pale skin
  • Crying out during sleep
  • Sweating, chills and clamminess
  • Irritability or impatience
  • Argumentative or combative
  • Confusion, including delirium
  • Rapid/fast heartbeat
  • Lightheadedness or dizziness
  • Hunger and nausea
  • Sleepiness
  • Blurred/impaired vision
  • Tingling or numbness in the lips or tongue
  • Headaches
  • Weakness or fatigue
  • Anger, stubbornness, or sadness
  • Lack of coordination
  • Nightmares or crying out during sleep

Some symptoms of hypoglycemia during sleep are:

  • crying out or having nightmares
  • sweating enough to make your pajamas or sheets damp
  • feeling tired, irritable, or confused after waking up

As hypoglycemia worsens, signs and symptoms may include:

  • Confusion, abnormal behavior or both, such as the inability to complete routine tasks
  • Visual disturbances, such as blurred vision
  • Seizures
  • Loss of consciousness
  • If left untreated it may cause death

People with severe hypoglycemia may appear as if they’re intoxicated. They may slur their words and move clumsily.

Many conditions other than hypoglycemia may cause these signs and symptoms. A blood sample to test your blood sugar level at the time of these signs and symptoms is how to know for sure that hypoglycemia is the cause.

Diabetic ketoacidosis

Diabetic ketoacidosis, sometimes called DKA, is an emergency, dangerous and serious condition in which extreme hyperglycemia (high blood sugar level), along with a severe lack of insulin. As a result, your body starts burning its stores of fat for energy instead. This process produces by-products called ketones. As the level of ketones in the body increases – an accumulation of ketones in the blood and urine, diabetic ketoacidosis can lead to dehydration and confusion. Signs of diabetic ketoacidosis are nausea, vomiting, stomach pain, fruity odor on the breath, and rapid (Kussmaul) breathing. If not treated, people with ketoacidosis can become unconscious and can die.

  • Diabetic ketoacidosis is characterized by a serum glucose level greater than 250 mg per dL (13.9 mmol/L), a pH less than 7.3, a serum bicarbonate level less than 18 mEq per L, an elevated serum ketone level, and dehydration.

Diabetic ketoacidosis usually occurs in people with type 1 diabetes. It is rare in type 2 diabetes – a third of diabetic ketoacidosis cases occur in those with type 2 diabetes. Although most cases of diabetic ketoacidosis affect people over the age of 20 and the great majority of diabetic ketoacidosis cases in kids aren’t fatal, this condition is still the No. 1 killer of children and adolescents with type 1 diabetes. And in some instances, people discover that they have diabetes after they land in the hospital with diabetic ketoacidosis. So it’s important to know the signs of diabetic ketoacidosis—and how to avoid it.

Diabetic ketoacidosis can occur in persons of all ages, with 14 percent of cases occurring in persons older than 70 years, 23 percent in persons 51 to 70 years of age, 27 percent in persons 30 to 50 years of age, and 36 percent in persons younger than 30 years 2). The case fatality rate is 1 to 5 percent 3). About one-third of all cases are in persons without a history of diabetes mellitus.

In a study of 28,770 persons younger than 20 years (mean age of 14 years) with diabetes, 94 percent had no episodes of diabetic ketoacidosis, 5 percent had one episode, and 1 percent had at least two episodes 4). Additionally, diabetic ketoacidosis occurred more often in females, in persons with a migration background, and in persons 11 to 15 years of age 5). Diabetic ketoacidosis has a case fatality rate of 1 to 5 percent 6). Although the highest rate of mortality is in older adults and persons with comorbid conditions, diabetic ketoacidosis is the leading cause of death in persons younger than 24 years with diabetes, most often because of cerebral edema 7).

Although people with diabetic ketoacidosis typically have a history of diabetes, 27 to 37 percent have newly diagnosed diabetes 8). This is especially true in young children. Most persons with diabetic ketoacidosis have type 1 diabetes. There is also a subgroup of persons with type 2 diabetes who have ketosis-prone diabetes; this subgroup represents 20 to 50 percent of persons with diabetic ketoacidosis 9). Persons with ketosis-prone diabetes have impaired insulin secretion; however, with proper glucose management, beta cell function improves and the clinical course resembles that of type 2 diabetes 10). These persons are often black or Latino, male, middle-aged, overweight or obese, have a family history of diabetes, and have newly diagnosed diabetes 11).

People with type 1 diabetes and children are at greater risk for diabetic ketoacidosis than those with type 2 and adults, respectively. One reason that kids are prone to diabetic ketoacidosis is illness, which can trigger diabetic ketoacidosis. Children are sick more often, largely because they spend a lot of time in close association with other children. However, when sick, adults with diabetes, especially type 1, may also develop diabetic ketoacidosis. Illness increases the levels of stress hormones in the body, the same hormones that counteract insulin and raise blood glucose levels. Nausea and vomiting can also cause dehydration (especially dangerous in infants and toddlers), which can increase the risk for diabetic ketoacidosis. Plus, if people don’t feel like eating, they may not think to take at least some of their mealtime insulin.

Also, certain ethnic groups get ketosis-prone diabetes, such as those of West African descent. Low-income people have more diabetic ketoacidosis episodes than others, because people just stop taking insulin. A lot of them are patients who don’t have access to their medications because of cost. Another contributing factor is drug abuse. When you are busy using substances, your insulin becomes less of a need. Plus, some illicit substances, such as cocaine, can drive up levels of anti-insulin hormones, pushing the body toward diabetic ketoacidosis.

The symptoms of diabetic ketoacidosis include high blood glucose, high levels of ketones in the urine, and:

  • quick breathing (Kussmaul) 
  • flushed cheeks
  • abdominal pain
  • breath that smells like sweet acetone (similar nail polish remover)
  • vomiting
  • dehydration.

Diabetic ketoacidosis is a serious condition that requires immediate assessment and treatment in the hospital. If someone you know has diabetes and becomes confused or unconscious, or has the symptoms listed above, call your local emergency number for an ambulance.


What are the Warning Signs of diabetic ketoacidosis?

Diabetic ketoacidosis usually develops slowly. But when vomiting occurs, this life-threatening condition can develop in a few hours.

Early symptoms include the following:

  • Thirst or a very dry mouth
  • Frequent urination
  • High blood glucose (blood sugar) levels
  • High levels of ketones in the urine

Then, other symptoms appear:

  • Constantly feeling tired
  • Dry or flushed skin
  • Nausea, vomiting, or abdominal pain
  • Vomiting can be caused by many illnesses, not just ketoacidosis. If vomiting continues for more than 2 hours, contact your health care provider.
  • Difficulty breathing
  • Fruity odor on breath
  • A hard time paying attention, or confusion

Checking your blood sugar and ketone levels

Check your blood sugar level if you have symptoms of diabetic ketoacidosis.

You can detect ketones with a simple urine test using a test strip, similar to a blood testing strip. Ask your health care provider when and how you should test for ketones. If your blood sugar is 11 mmol/L or over and you have a blood or urine ketone testing kit, check your ketone level. Many experts advise to check your urine for ketones when your blood glucose is more than 250 mg/dL (13.9 mmol/L).

When you are ill (when you have a cold or the flu, for example), check for ketones every 4 to 6 hours. And check every 4 to 6 hours when your blood glucose is more than 250 mg/dL (13.9 mmol/L).

Also, check for ketones when you have any symptoms of diabetic ketoacidosis.

When to test for ketones?

People with insulin dependent diabetes should take a ketone test:

  • Any time your blood sugar is over 17 mmol/l (300 mg/dl)
  • If sugar levels have repeatedly been over 13 mmol/l (230 mg/dl)
  • If you are unwell and have any of the symptoms of ketoacidosis

If you do a blood ketone test:

  • lower than 10.8 mg/dL (0.6 mmol/L) is a normal reading
  • 10.8 to 27 mg/dL (0.6 to 1.5 mmol/L) means you’re at a slightly increased risk of diabetic ketoacidosis and should test again in a couple of hours
  • 28.8 to 52.2 mg/dL (1.6 to 2.9 mmol/L) means you’re at an increased risk of diabetic ketoacidosis and should contact your diabetes team or doctor as soon as possible
  • 54 mg/dL (3 mmol/L) or over means you have a very high risk of diabetic ketoacidosis and should get medical help immediately

If you do a urine ketone test, a result of more than 2+ means there’s a high chance you have diabetic ketoacidosis.

Do NOT exercise when your urine tests show ketones and your blood glucose is high. High levels of ketones and high blood glucose levels can mean your diabetes is out of control. Check with your health care provider about how to handle this situation.

Hyperglycaemic hyperosmolar syndrome

Diabetic hyperosmolar syndrome also known as hyperosmolar hyperglycaemic state, is a serious condition caused by extremely high blood sugar levels.

Hyperosmolar hyperglycaemic state can affect both types of diabetics, yet it usually occurs amongst middle-aged and older adults with type 2 diabetes.

Usually, hyperosmolar hyperglycaemic state is brought on by an illness or infection.

Your blood sugar level of 600 milligrams per deciliter (600 mg/dL) or 33.3 millimoles per liter (33.3 mmol/L) or higher

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, seizures, a diabetic coma and even death.

Who is at risk of Hyperosmolar Hyperglycaemic State?

Periods of illness can significantly raise blood glucose levels, which could lead to Hyperosmolar Hyperglycaemic State if medication is not sufficient to lower sugar levels.

Having blood glucose levels above 33 mmol/l (600 mg/dl) for extended periods of time presents a risk of Hyperosmolar Hyperglycaemic syndrome occurring.

Some serious complications of diabetes, such as Hyperosmolar Hyperglycemic Nonketotic Syndrome, usually manifest themselves amongst older people, who may be less aware of high blood glucose levels and how to treat them.

Diabetic hyperosmolar syndrome symptoms

Diabetic hyperosmolar syndrome can take days or weeks to develop.

Possible signs and symptoms of diabetic hyperosmolar syndrome include:

  • Blood sugar level of 600 milligrams per deciliter (600 mg/dL) or 33.3 millimoles per liter (33.3 mmol/L) or higher
  • Excessive thirst
  • Dry mouth
  • Increased urination
  • Warm, dry skin
  • Fever
  • Drowsiness, confusion
  • Feeling sleepy
  • Hallucinations
  • Vision loss
  • Convulsions
  • Coma

What is the best way for people with diabetes to avoid Hyperosmolar Hyperglycaemic State?

If you keep on top of your blood sugar levels, it is possible to avoid Hyperosmolar Hyperglycaemic State. By checking blood glucose regularly, people with diabetes can take action if a reading falls outside their target blood glucose range.

Your healthcare professionals should be able to advise on an effective blood glucose range and what to do if your readings fall outside of it.

Risk factors for diabetic coma

Anyone who has diabetes is at risk of a diabetic coma.

If you have type 1 diabetes, you’re more at risk of a diabetic coma caused by:

  • Low blood sugar (hypoglycemia)
  • Diabetic ketoacidosis

If you have type 2 diabetes, you’re generally more at risk of a diabetic coma caused by:

  • Diabetic hyperosmolar syndrome, especially if you’re middle-aged or older

If you have either type 1 or type 2 diabetes, the following factors can increase the risk of a diabetic coma:

  • Insulin delivery problems. If you’re on an insulin pump, you have to check your blood sugar frequently. One of the reasons for this is that a kink in the insulin pump tubing may stop all insulin delivery without you being aware of it.Even tubeless pumps can sometimes have problems that cause insulin delivery to stop. A lack of insulin can quickly lead to diabetic ketoacidosis if you have type 1 diabetes.
  • An illness, trauma or surgery. When you’re sick or injured, blood sugar levels tend to rise, sometimes dramatically. This may cause diabetic ketoacidosis if you have type 1 diabetes and don’t increase your insulin dosage to compensate.Other medical conditions, such as congestive heart failure or kidney disease, may increase your risk of diabetic hyperosmolar syndrome.
  • Poorly managed diabetes. If you don’t monitor your blood sugar properly or take your medications as directed, you’ll have a higher risk of developing long-term complications and a diabetic coma.
  • Deliberately skipping insulin. Sometimes, people with diabetes who also have an eating disorder choose not to use their insulin as directed with the hope of losing weight. This is a dangerous, life-threatening practice that increases the risk of a diabetic coma.
  • Drinking alcohol. Alcohol can have unpredictable effects on your blood sugar, sometimes dropping blood sugar levels as late as a day or two after the alcohol was consumed. This can increase your risk of a diabetic coma caused by hypoglycemia.
  • Illegal drug use. Illegal drugs, such as cocaine and Ecstasy, can increase your risk of severe high blood sugar levels, as well as your risk of a diabetic coma.

Diabetic coma prevention

Good day-to-day control of your diabetes can help you prevent a diabetic coma. Keep these tips in mind:

  • Follow your meal plan. Consistent snacks and meals can help you control your blood sugar level.
  • Keep an eye on your blood sugar level. Frequent blood sugar tests can tell you whether you’re keeping your blood sugar level in your target range — and alert you to dangerous highs or lows. Check more frequently if you’ve exercised because exercise can cause blood sugar levels to drop, especially if you don’t exercise regularly.
  • Take your medication as directed. If you have frequent episodes of high or low blood sugar, let your doctor know. He or she may need to adjust the dose or the timing of your medication.
  • Have a sick-day plan. Illness can elevate blood sugar unexpectedly. Before you get sick, talk with your doctor about how to best manage this increase in your blood sugar.
  • Check for ketones when your blood sugar is high. Check your urine for ketones when your blood sugar level is more than 240 mg/dL (13.3 mmol/L), especially if you are sick. If you have a large amount of ketones, call your doctor for advice. Call your doctor immediately if you have any level of ketones and are vomiting.
  • Have glucagon and fast-acting sources of sugar available. If you take insulin for your diabetes, make sure you have an up-to-date glucagon kit and fast-acting sources of sugar, such as glucose tablets or orange juice, readily available to treat low blood sugar levels.
  • Consider a continuous glucose monitor (CGM), especially if you have trouble maintaining stable blood sugar levels or you don’t feel symptoms of low blood sugar (hypoglycemia unawareness).Continuous glucose monitors are devices that use a small sensor inserted underneath the skin to track trends in your blood sugar levels and transmit the information to a wireless device.These devices can alert you when your blood sugar is dangerously low or if it is dropping too fast. However, you still need to test your blood sugar levels using a blood glucose meter even if you’re using a continuous glucose monitor. Continuous glucose monitors are more expensive than conventional glucose monitoring methods, but they may help you control your glucose better.
  • Drink alcohol with caution. Because alcohol can have an unpredictable effect on your blood sugar, be sure to have a snack or a meal when you drink, if you choose to drink at all.
  • 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 administer a glucagon injection. If needed, someone should summon emergency help should you pass out.
  • Wear a medical ID bracelet or necklace. If you’re unconscious, the ID can provide valuable information to your friends, co-workers and others — including emergency personnel.

Diabetic coma signs and symptoms

Before developing a diabetic coma, you’ll usually experience signs and symptoms of high blood sugar or low blood sugar.

High blood sugar (hyperglycemia)

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

  • Increased thirst
  • Frequent urination
  • Fatigue
  • Nausea and vomiting
  • Shortness of breath
  • Stomach pain
  • Fruity breath odor
  • A very dry mouth
  • A rapid heartbeat

Low blood sugar (hypoglycemia)

Signs and symptoms of a low blood sugar level may include:

  • Shakiness or nervousness
  • Anxiety
  • Fatigue
  • Weakness
  • Sweating
  • Hunger
  • Nausea
  • Dizziness or light-headedness
  • Difficulty speaking
  • Confusion

Some people, especially those who’ve had diabetes for a long time, develop a condition known as hypoglycemia unawareness and won’t have the warning signs that signal a drop in blood sugar.

If you experience any symptoms of high or low blood sugar, test your blood sugar and follow your diabetes treatment plan based on the test results. If you don’t start to feel better quickly, or you start to feel worse, call for emergency help.

Diabetic coma diagnosis

If you experience a diabetic coma, 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. If you have diabetes, you may want to wear a medical ID bracelet or necklace.

Lab tests

You may need various lab tests to measure:

  • Your blood sugar level
  • Your ketone level
  • The amount of nitrogen or creatinine in your blood
  • The amount of potassium, phosphate and sodium in your blood

Diabetic coma treatment

The type of emergency treatment for a diabetic coma depends on whether your blood sugar level is too high or too low.

High blood sugar

If your blood sugar level is too high, you may need:

  • Intravenous fluids to restore water to your tissues
  • Potassium, sodium or phosphate supplements to help your cells function correctly
  • Insulin to help your tissues absorb the glucose in your blood
  • Treatment for any underlying infections

Low blood sugar

If your blood sugar level is too low, you may be given a glucagon injection, which will cause your blood sugar level to quickly rise. Intravenous dextrose may also be given to raise blood glucose levels.

Consciousness typically returns when blood sugar reaches a normal level.

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