Which of the following is NOT a sign or symptom of Addison's disease?

In the context of Addison's disease, the correct choice highlights that hyperglycemia is not a typical manifestation of this condition. Addison's disease, or primary adrenal insufficiency, occurs when the adrenal glands do not produce sufficient amounts of cortisol and, sometimes, aldosterone. This leads to various signs and symptoms related to cortisol deficiency.

Hyperpigmentation is common due to increased production of adrenocorticotropic hormone (ACTH), which can stimulate melanocytes, leading to darker skin. Weight loss is frequently observed as the body struggles to maintain metabolic homeostasis in the face of adrenal insufficiency. Muscle weakness is another symptom attributed to inadequate cortisol levels, which are crucial for energy metabolism and muscle function.

In contrast, hyperglycemia is not associated with Addison's disease. In fact, decreased cortisol levels typically result in lower blood sugar levels, as cortisol plays a vital role in gluconeogenesis and maintaining blood glucose levels. Therefore, understanding the hormonal imbalances caused by Addison's disease helps clarify why hyperglycemia would not be a symptom of this disorder.