Diabetic ketoacidosis medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Medical Therapy
Treatment consists of hydration to lower the osmolality of the blood, replacement of lost electrolytes, insulin to force glucose and potassium into the cells, and eventually glucose simultaneously with insulin in order to correct other metabolic abnormalities, such as lowered blood potassium (hypokalemia) and elevated ketone levels. Many patients require admission to a step-down unit or an intensive care unit (ICU) so that vital signs, urine output, and blood tests can be monitored frequently. Brain edema is not rare, and so this may suggest intensive monitoring as well. In patients with severe alteration of mental status, intubation and mechanical ventilation may be required. Survival is dependent on how badly-deranged the metabolism is at presentation to a hospital, but the process is only occasionally fatal. DKA occurs more commonly in type 1 diabetes because insulin deficiency is most severe, though it can occur in type 2 diabetes. In about a quarter of young people who develop type 1 diabetes, insulin deficiency and hyperglycemia lead to ketoacidosis before the disease is recognized and treated. This can occur at the onset of type 2 diabetes as well, especially in young people. In a person known to have diabetes and being adequately treated, DKA usually results from omission of insulin, mismanagement of acute gastroenteritis, the flu, or the development of a serious new health problem (e.g., bacterial infection, myocardial infarction).
Insulin deficiency switches many aspects of metabolic balance in a catabolic direction. The liver becomes a net producer of glucose by way of gluconeogenesis (from protein) and glycogenolysis (from glycogen, though this source is usually exhausted within hours). Fat in adipose tissue is reduced to triglycerides and fatty acids by lipolysis. Muscle is degraded to release amino acids for gluconeogenesis. The rise of fatty acid levels is accompanied by increasing levels of ketone bodies (acetone, acetoacetate and beta-hydroxybutyrate; only one, acetone, is chemically a ketone -- the name is an historical accident). As ketosis worsens, it produces a metabolic acidosis, with anorexia, abdominal distress, and eventually vomiting. The rising level of glucose increases the volume of urine produced by the kidneys (an osmolar diuresis). The high volume of urination (polyuria) also produces increased losses of electrolytes, especially sodium, potassium, chloride, phosphate, and magnesium. Reduced fluid intake from vomiting combined with amplified urination produce dehydration. As the metabolic acidosis worsens, it induces obvious hyperventilation (termed Kussmaul respiration). Kussmaul's respirations are the body's attempt to remove carbon dioxide from the blood that would otherwise form carbonic acid and further worsen the ketoacidosis. See also arterial blood gas.
On presentation to hospital, patients in DKA are typically suffering dehydration and breathing both fast and deeply. Abdominal pain is common and may be severe. Consciousness level is typically normal until late in the process, when obtundation (dulled or reduced level of alertness or consciousness) may progress to coma. Dehydration can become severe enough to cause shock. Laboratory tests typically show hyperglycemia, metabolic acidosis, normal or elevated potassium, and severe ketosis. Many other tests can be affected.
At this point the patient is urgently in need of intravenous fluids. The basic principles of DKA treatment are:
- Rapid restoration of adequate circulation and perfusion with isotonic intravenous fluids
- Gradual rehydration and restoration of depleted electrolytes (especially sodium and potassium), even if serum levels appear adequate
- Insulin to reverse ketosis and lower glucose levels
- Careful monitoring to detect and treat complications
Treatment usually results in full recovery, though death can result from inadequate treatment or a variety of complications, such as cerebral edema (occurs mainly in children).