What lab findings are commonly associated with Cushing's syndrome?

Cushing's syndrome is characterized by an excess of cortisol production, which can arise from a variety of causes, including pituitary adenomas, adrenal tumors, or ectopic ACTH production. In most cases, patients will present with elevated levels of both cortisol and adrenocorticotropic hormone (ACTH) if the cause is not an adrenal tumor, as the pituitary gland continues to produce ACTH in response to the body’s feedback mechanisms.

In primary adrenal causes of Cushing's syndrome, such as adrenal adenomas or carcinomas, cortisol will be elevated while ACTH might be low due to negative feedback on the pituitary gland. However, in secondary causes, like Cushing's disease (often due to a pituitary adenoma), both ACTH and cortisol levels are elevated.

This understanding of the hormonal feedback loop helps to clarify that the most common laboratory finding associated with Cushing's syndrome includes elevated levels of cortisol and often elevated or inappropriately normal ACTH, depending on the underlying cause.

The other answer choices do not align with the typical presentations of Cushing's syndrome. Low aldosterone and cortisol would not be consistent with the syndrome, and elevated insulin and glucagon are more related to metabolic disorders, such as diabetes