What finding should the nurse identify as a manifestation of type 1 diabetes mellitus?

The presence of ketones in the urine is a significant finding associated with type 1 diabetes mellitus. This occurs because, in type 1 diabetes, the body does not produce insulin, which is necessary for glucose uptake into cells. Without sufficient insulin, the body begins to break down fats for energy, a process that results in the production of ketones. When ketones accumulate in the blood, they can lead to a condition called diabetic ketoacidosis, which is a serious and potentially life-threatening condition.

While fatigue is also a common symptom of type 1 diabetes due to the lack of glucose entering cells for energy, it is not as specific as the presence of ketones. High blood pressure can occur in patients with diabetes but is not a direct manifestation specific to type 1 diabetes. Excessive sweating is less commonly associated with this condition and does not directly indicate the hyperglycemic state or metabolic changes characteristic of type 1 diabetes. Therefore, the presence of ketones in urine is the most defining characteristic among the options provided.