The PMHNP is treating a 17-year-old girl who is an inpatient on an eating disorder unit. This patient has type 1 diabetes in addition to bulimia nervosa. Today she complains of dizziness, nausea, confusion, and weakness. What is her most likely diagnosis?

Choice A reason: Severe dehydration can cause dizziness and weakness, but the presence of confusion and nausea in a type 1 diabetic patient raises concern for metabolic disturbance rather than isolated dehydration. Choice B reason: Diabetic ketoacidosis (DKA) is characterized by hyperglycemia, ketonemia, dehydration, nausea, vomiting, weakness, and altered mental status. Patients with type 1 diabetes, particularly those with eating disorders, are at increased risk due to insulin omission or inadequate intake. Choice C reason: Acute renal failure can present with nausea, confusion, and weakness, but there is no information suggesting a sudden change in kidney function or laboratory evidence in this scenario. Choice D reason: Myocardial toxicity is unlikely in this presentation; while electrolyte disturbances may affect the heart, the immediate constellation of symptoms in a type 1 diabetic points more toward DKA.