One type results in about 100,000 hospitalizations a year with a mortality rate of under 5%. The other is thought to cause fewer hospitalizations, yet the mortality rate is about 15%. Severe hyperglycemic conditions, known as diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS), involve very serious imbalances in blood chemistry and usually require that a person be hospitalized until normal blood chemistry is restored. Because they can occur in anyone with diabetes, everyone should know what causes them, how to prevent them, how they are treated, and when to seek medical attention.
The body in balance
Glucose metabolism is a complex balancing act. In people who don’t have diabetes, a number of interconnected processes help the body to use glucose and keep blood glucose levels in the normal range. The body constantly balances glucose extracted from foods and produced by the liver with glucose utilization by the body’s tissues. When there is ample glucose in the bloodstream, the liver converts some of it into glycogen for storage. When the body needs more energy, such as during a prolonged period of fasting or activity, the liver converts stored glycogen back into glucose so that it can be used by the body’s tissues. The liver also can create glucose from amino acids and fats.
Insulin lowers blood glucose levels both by slowing down the liver’s glucose production and by helping the body’s tissues to use glucose for energy. If the blood glucose level goes too low, other hormones, called counterregulatory hormones, work against the action of insulin to raise blood glucose levels. These hormones include glucagon, epinephrine, growth hormone, and cortisol. All work by prodding the liver to release glucose and by limiting glucose utilization by the body’s tissues.
In diabetes, this delicate balance is disrupted. People with Type 1 diabetes do not produce insulin, so they must inject it. They may have deficient or altered counterregulatory responses as well. People with Type 2 diabetes either do not produce enough insulin or do not respond properly to insulin, or both. They, too, must take steps to control their blood glucose with diet, exercise, or diabetes pills or insulin. If blood glucose control measures don’t work, high blood sugar is one of the possible, undesired results.
What sets the stage for diabetic ketoacidosis (DKA) is hyperglycemia (high blood sugar), especially when there is not enough insulin to handle it. In the absence of insulin, at least two things happen: The liver begins to produce more glucose, and the body’s fat and muscle cells are unable to use glucose for energy and begin to starve. The body reacts to starvation by releasing counterregulatory hormones, which signal the liver to break down fat cells for energy. But because the liver and fat cells are unable to use the glucose in the bloodstream, they are unable to properly and completely break down the fat. Instead, they stop at a chemical “halfway point,” producing chemical by-products called ketones.
Soon, the bloodstream gets flooded with excessive amounts of these ketones, rendering it more and more acidic. At the same time, the kidneys begin filtering large amounts of glucose from the blood and producing large amounts of urine. As the person urinates more frequently, the body becomes dehydrated and loses important minerals called electrolytes, which include sodium, potassium, and calcium. Having the proper amount of electrolytes is critical to many body functions, including the contraction and relaxation of the heart muscle. If not treated, all of these serious imbalances can eventually lead to coma and death.