The mother of a 16-year-old boy with type 1 diabetes mellitus who uses an insulin pump brings him to the emergency department. She reports he has been fighting the stomach flu for the past 36 hours, and she found him sluggish and confused in bed this morning. On examination, the patient is lethargic and weak and oriented to self only. He has a fruity odorous breath when he speaks. His vital signs are blood pressure $88 / 55 \mathrm{~mm} \mathrm{Hg}$, heart rate 132 beat $/ \mathrm{min}$, respiratory rate $32 / \mathrm{min}$, temperature $100.5^{\circ} \mathrm{F}$, and pulse oximetry of $98 \%$ on room air. The emergency department physician orders laboratory work to check electrolytes and a blood gas.
- What is the likely diagnosis of this patient, and what are the contributing factors that could have led to this diagnosis?
- What is the usual course of treatment for a patient with diabetic ketoacidosis (DKS)?
- Why is it important not to treat the high blood sugar too aggressively, too fast?
- In DKA, why does potassium need to be replaced, and what monitoring is necessary prior to starting potassium replacement?