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, nausea, and her history of diabetes raises concern for metabolic complications rather than isolated fluid loss. Choice B reason: Diabetic ketoacidosis is characterized by hyperglycemia, ketonemia, metabolic acidosis, and dehydration. The patient’s symptoms of dizziness, nausea, confusion, and weakness are consistent with this potentially life-threatening complication of type 1 diabetes, which may be exacerbated by eating disorder behaviors such as vomiting or insulin manipulation. Choice C reason: Acute renal failure typically presents with oliguria, fluid retention, and electrolyte disturbances. While kidney injury may develop as a complication, it does not directly explain the acute symptom cluster observed here. Choice D reason: Myocardial toxicity may present with arrhythmias or heart failure symptoms but is less likely in the context of acute metabolic and neurological symptoms in a diabetic adolescent.