Which symptom indicates that a client may be experiencing diabetic ketoacidosis?

In the context of diabetic ketoacidosis (DKA), the symptom that most accurately indicates the condition is excessive thirst. This happens because DKA results from insufficient insulin, which causes the body to break down fat for fuel, leading to ketone production that can acidify the blood. As blood glucose levels rise, the kidneys attempt to excrete the excess sugar through urine, leading to increased urination, known as polyuria. The dehydration that follows this frequent urination contributes to the sensation of excessive thirst, medically referred to as polydipsia.

Anuria, the absence of urine, is not a typical symptom of DKA. In fact, patients usually experience an increase in urination due to high blood sugar levels that exceed renal threshold. Frequent urination is a common symptom, but excessive thirst is particularly key as it reflects the body's response to dehydration. Unexplained weight gain does not align with DKA, as this condition typically leads to weight loss due to the breakdown of fat and muscle as the body seeks alternative energy sources. Therefore, excessive thirst serves as a critical indicator of the dehydration that accompanies diabetic ketoacidosis.