The presentation of confusion, dehydration, a blood glucose of 600 mg/dL, and positive urine ketones strongly indicates diabetic ketoacidosis (DKA). DKA is characterized by hyperglycemia, ketosis, and metabolic acidosis. Immediate treatment involves IV fluids to correct dehydration and insulin to reduce blood glucose and stop ketone production. This approach counteracts the underlying insulin deficiency causing ketogenesis and hyperglycemia. Electrolytes should also be monitored, especially potassium, but initial management prioritizes fluid resuscitation and insulin administration. This prevents progression to serious complications such as cerebral edema or cardiac arrhythmias.
Reference: Harrison's Principles of Internal Medicine, Jameson et al., 20th Edition.