A 28-year-old man with type 1 diabetes mellitus comes to the emergency department due to abdominal pain, nausea, and vomiting for the past 2 days. The patient has a history of medical noncompliance and has not used insulin for the past 5 days. Temperature is 36.7 C (98.1 F), blood pressure is 96/62 mm Hg, pulse is 112/min, and respirations are 26/min. Examination shows dry mucous membranes. The abdomen is soft with mild, diffuse tenderness. Laboratory results are as follows: Serum and urine are positive for ketones. Which of the following is the best index to monitor the response to treatment of this patient's condition?

Question

A 28-year-old man with type 1 diabetes mellitus comes to the emergency department due to abdominal pain, nausea, and vomiting for the past 2 days.  The patient has a history of medical noncompliance and has not used insulin for the past 5 days.  Temperature is 36.7 C (98.1 F), blood pressure is 96/62 mm Hg, pulse is 112/min, and respirations are 26/min.  Examination shows dry mucous membranes.  The abdomen is soft with mild, diffuse tenderness.  Laboratory results are as follows:  Serum and urine are positive for ketones.  Which of the following is the best index to monitor the response to treatment of this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d199_d81b_bc81_8d5c122e9ec7_MD0003_00 This patient's presentation (hyperglycemia with anion gap metabolic acidosis) is consistent with diabetic ketoacidosis (DKA). Treatment of DKA includes prompt intravenous fluid resuscitation, insulin to lower serum glucose and ketones, and electrolyte replacement. Frequent clinical and laboratory monitoring is indicated: the anion gap, electrolytes, and venous pH are measured every 2-4 hours, and serum glucose is measured hourly. A primary derangement in DKA is anion gap metabolic acidosis generated by the unmeasured ketoacid anions acetoacetate and beta-hydroxybutyrate. Beta-hydroxybutyrate is derived from the reduction of acetoacetic acid and can become the predominant ketoacid in severe DKA. With volume resuscitation and correction of hyperosmolality and hyperglycemia, these ketoacids disappear and the anion gap normalizes, pointing to resolution of ketosis. Posttreatment hyperchloremic acidosis may occur due to infusion of normal saline; however, the anion gap will be normal. Resolution of DKA is further supported by normalization of the venous pH and serum beta-hydroxybutyrate levels, rise in serum bicarbonate, and tolerance of oral food intake. Measurement of serum and urine glucose alone is inappropriate for monitoring response to treatment because ketosis and acidemia may still be present even when glucose levels drop below 200-250 mg/dL (Choice D). (Choice A) Effective plasma osmolality is often severely elevated in DKA due to dehydration and hyperglycemia. With prompt volume resuscitation and intravenous insulin treatment, serum osmolality may normalize, but ketosis and anion gap acidosis may still be present. Therefore, serum osmolality is not a sensitive marker for monitoring resolution of ketonemia. Effective plasma osmolality (Choices B and E) Urine ketone testing primarily measures acetoacetate, not beta-hydroxybutyrate. Therefore, although measurement of urine or serum acetoacetate is appropriate for DKA diagnosis, these tests should not be used to monitor for DKA resolution. In addition, ketone byproducts are often persistently elevated in the urine, even after ketoacidosis resolution. Measurement of serum beta-hydroxybutyrate (not acetoacetate), along with measurement of the anion gap, is an accurate method for monitoring ketosis resolution. Educational objective: The most accurate markers indicating resolution of diabetic ketoacidosis are the serum anion gap and serum beta-hydroxybutyrate levels. The anion gap estimates the unmeasured anion concentration in the blood and returns to normal with the disappearance of ketoacid anions. References: Management of adult diabetic ketoacidosis. (http://www.ncbi.nlm.nih.gov/pubmed/25061324)

A 28-Year-Old Man with Type 1 Diabetes Mellitus Comes to the Emergency