Diabetes mellitus (DM) has many complications, emphasizing the importance of controlling one's blood glucose. There is another reason, however, to regularly manage DM: the risk of elevated blood glucose (hyperglycemia) that is serious enough to be a medical emergency. Such hyperglycemic emergencies can involve diabetic ketoacidosis or hyperosmolar coma.
Diabetic Ketoacidosis
Diabetic ketoacidosis (DKA) is mostly associated with DM type 1 but can occur with DM type 2. This condition is caused by a significant insulin deficiency, which in turn may be due to absent delivery of insulin (e.g., noncompliance) and/or stressors (e.g., infection). The result is a series of metabolic processes that produce a life-threatening condition.
Insulin normally inhibits the formation of new glucose by the liver (gluconeogenesis), the breakdown of stored glycogen into glucose (glycogenolysis), and the breakdown of fat (lipolysis). When insulin is very low or absent, these three processes begin to deliver glucose and free fatty acids into the bloodstream. While this glucose produces hyperglycemia, the free fatty acids are metabolized with an excessive portion converted into acidic ketones.
Patients with DKA have massive urination, dehydration, and thirst due to hyperglycemia and altered consciousness due to dehydration and ketoacidosis. They may also experience nausea, vomiting, and abdominal pain. Blood tests reveal a glucose level greater than 250 milligrams per deciliter (mg/dL), ketones greater than 5 milliequivalents per liter (mEq/L), pH less than 7.2, and bicarbonate less than or equal to 18 mEq/L. Ketones can also be detected in the urine.
The treatment of DKA must address dehydration, hyperglycemia, and acidosis. Liters of intravenous (IV) fluids, either isotonic saline or lactated Ringer solution, are given over several hours. For hyperglycemia, a continuous insulin drip is administered and slowed as the glucose level approaches normal. Acidosis should correct with measures for dehydration and hyperglycemia, though sodium bicarbonate is available for life-threatening acidosis. Other steps involve addressing electrolyte abnormalities and conditions that may have triggered DKA. Throughout treatment, laboratory blood tests are checked frequently to monitor its progress.
Hyperosmolar Coma
Hyperosmolar coma (HC), also referred to as nonketotic hyperosmolar coma, occurs most often in patients with DM type 2 but can occur in those with DM type 1. This condition is triggered by a combination of insulin resistance, absent delivery of insulin, and stressors that significantly limits the activity of available insulin. Unlike DKA, HC does not involve ketoacidosis because some insulin is still present to inhibit lipolysis and, therefore, ketone production.
The pathophysiologic process of HC is otherwise similar to that of DKA. Inadequate insulin activity allows gluconeogenesis and glycogenolysis to take place and produce hyperglycemia. This leads to excessive urination, dehydration, and thirst. When the blood has less water and more glucose, it becomes concentrated (hyperosmolar) enough to alter the patient's level of consciousness. Blood tests demonstrate a glucose level that approaches or exceeds 1,000 mg/dL but no excessive ketones.
Like DKA, the treatment of HC involves IV fluids to correct dehydration and continuous infusion of insulin to manage hyperglycemia. Electrolyte abnormalities and conditions that may have triggered HC should also be addressed.
Final Words
DKA and HC are serious medical emergencies. However, with proper instruction for managing DM, one can minimize the frequency of these severe hyperglycemic episodes.
