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

1. You are correct! The child most likely has Type One diabetes. The high levels of glucose indicate that the body is not properly using the sugar that the child is consuming, possible due to increased insulin production in the pancreas. Ketonuria results when the body is incorrectly processes that sugar, and begins breaking down fat instead of sugar. Fat metabolism results in ketones as a byproduct which must be excreted from the body in urine.

2.

When the body increases the breakdown of fat, it can cause an associated increase of acid build-up (metabolic acidosis). Metabolic acidosis also causes flushed, warm, dry skin, as well as nausea and vomiting. Sweet smelling breath can be explained by the the body breaking down fats, as the body releases ketones through respiration, as well as through urine, as previously mentioned. The patient's excessive thirst can be explained by osmoreceptor activation in response to the change in osmolarity due to high levels of blood glucose. In response, the increased fluid will cause increases in pulse and urination. Because the patient's body is unable to break down glucose necessary for energy, he appears slow and lethargic. The patient is experiencing an increase in appetite because the body isn't breaking down glucose, and therefore perceives that the boy isn't eating enough, despite high levels of glucose.