Final answer:
Cushing's syndrome, not Conn's disease, is associated with hyperglycemia, as it is characterized by an excess of cortisol that can cause high blood sugar levels and insulin resistance.
Step-by-step explanation:
Between Conn's disease and Cushing's syndrome, the accurate condition as a sign or symptom of hyperglycemia would be Cushing's syndrome. This endocrine disorder is characterized by an excess of the hormone cortisol in the body, which can lead to various symptoms including high blood sugar levels, obesity, high blood pressure, and a distinctive rounded face, among others. Hyperglycemia is commonly observed in patients with Cushing's syndrome because cortisol influences glucose metabolism and can lead to insulin resistance, a key feature in the development of diabetes.