Pathophysiology Clinical Vignette Question

Question

A 6-year-old boy is admitted to the emergency department with nausea, vomiting, and abdominal pain. He is very lethargic; his skin is warm, dry, and flushed; his pulse is rapid, and he has a sweet smell to his breath. His parents relate that he has been very thirsty during the past few weeks, his appetite has been poor, and he has been urinating frequently. His initial plasma glucose is 420mg/dL, and a urine test for ketones is strongly positive.  

1. What is the most likely cause of this boy’s elevated blood glucose and ketonuria?  I'm guessing that he has hyperglycemia and diabetic ketoacidosis. Is this correct?
2. Explain his presenting signs and symptoms in terms of the elevated blood glucose and metabolic acidosis.  

Answer 1

Yes that is correct. Diabetic ketoacidosis resulting from uncontrolled blood sugar usually appearing in what looks like new onset Type 1 Diabetes.

As blood sugar rises, without the presence of insulin due to autoimmune pancreatic islet cell destruction, the body (cells of the body) wants to absorb the glucose for use but cannot. Thus, the cells in the body begin to starve and shift towards breaking down fats for fuel releasing free fatty acids for ketotic metabolism (ketogenesis) . The ketones or ketoacids (β-hydroxybutyrate & acetoacetate) drive blood pH down. The Kussmaul breathing (rapid, deep breathing) occurs as the body attempts to expel the acid in the form of CO2. As the kidneys begin to expel ketones and excess sugar, this takes water along with it into the urine through osmotic diuresis causing dehydration (K+ is also loss through this process). K+ is also driven into the blood serum from the cells as the cells take up H+ in an attempt to stabilize the metabolic acidosis. This leads to hyperkalemia but a total body decrease in [K+]. The fruity odor breath smell is the ketone being released during exhalation. The increased ketone bodies in blood serum also begins to create delirium and neurocognitive change as they cross the BBB affect mental function.

Hope the explanation helps!