A 19-year-old woman presents to the emergency department with one week of lethargy and one day of diffuse abdominal pain. She also reports a ten-pound weight loss as frequent urination and excessive thirst. Her last menstrual period was 3 weeks ago. Past medical history is unremarkable, and she does not take any medications. She does not consume alcohol, smoke cigarettes, or use illicit drugs. Her vital signs are temperature 98.6°F (37.0°C), blood pressure 114/62 mmHg, pulse 115 beats/min, and respirations 24/min. On physical examination, she has dry mucous membranes, tachycardia, and tachypnea with a fruity odor to her breath. Abdominal examination reveals diffuse tenderness to palpation with no rebound or guarding.
Fingerstick blood glucose level is 390 mEq/L. Further lab results show a potassium level of 5.4 mEq/L, bicarbonate of 14 mEq/L, and a pH of 7.24. Which of the following is the most appropriate next step in the management of this patient?
C) Normal saline and regular insulin infusion
Diabetic ketoacidosis (DKA) severity is determined by the pH level, bicarbonate level, and mental status of the patient, not by blood glucose measurements. Moderate to severe DKA is categorized as follows:
- Moderate DKA: pH level between 7.0–7.24 and a serum bicarbonate level of 10–15 mEq/L
- Severe DKA: pH level less than 7.0 and bicarbonate less than 10 mEq/L
In a patient presenting with diabetic ketoacidosis (DKA) fluid repletion may be initiated with isotonic saline (0.9 percent sodium chloride [NaCl]) or isotonic buffered crystalloid (e.g., lactated Ringer solution). Dextrose 5% is added when serum glucose is less than or equal to 200 mg/dL. Most guidelines recommend initiating treatment with low-dose inravenous insulin in all patients with moderate to severe DKA who have a serum potassium ≥3.3 mEq/L. A switch to subcutaneous (SQ) basal-bolus insulin is made when the patient can eat and the glucose level is below 200 mg/dL. Bicarbonate is considered for patients with a pH less than or equal to 6.9 and is rarely indicated.
Other options are less appropriate:
Answer choice A: Half normal saline and regular insulin infusion, is incorrect. Half normal saline and regular insulin infusion is not appropriate because half normal saline is not the initial fluid of choice.
Answer choice B: Half normal saline and subcutaneous insulin administration, is incorrect. Half normal saline is not the initial fluid of choice; normal saline is usually preferred. Additionally, subcutaneous insulin administration is not appropriate for initial management of moderate to severe DKA which requires IV insulin.
Answer choice D: Normal saline and subcutaneous insulin administration, is incorrect. While normal saline is correct for fluid resuscitation, subcutaneous insulin is not appropriate for initial management. IV insulin is required to rapidly control hyperglycemia in moderate to severe DKA.
Answer choice E: Sodium bicarbonate and normal saline and regular insulin infusion, is incorrect. Sodium bicarbonate is only indicated in severe acidosis (pH ≤ 6.9). Without this indication, it should not be used routinely in DKA.
Key Learning Point
In the setting of DKA, fluid repletion may be initiated with isotonic saline or lactated Ringer solution. Continuous IV insulin should be administered to treat hyperglycemia in moderate to severe DKA. Insulin should be continued until the anion gap resolves. Potassium levels should be monitored, and potassium should be administered if the level falls below 5.3 mEq/L. Sodium bicarbonate should be used only for severe acidosis (pH ≤ 6.9).
