Abstract
Insulin treatment for diabetic ketoacidosis occasionally results in hypophosphatemia, which is often mild and does not require treatment. However, we experienced a case in which intravenous insulin administration resulted in myocardial injury and altered consciousness despite mild hypophosphatemia. Phosphate replacement therapy resulted in a marked improvement in symptoms. As overlapping conditions that result in hypophosphatemia can cause severe complications after insulin therapy for diabetic ketoacidosis, even in patients with mild hypophosphatemia, physicians should pay more attention to changes in phosphate levels in patients undergoing treatment for diabetic ketoacidosis.