Canadian Practical Nurse Registration Examination (CPNRE) Practice Exam

Cushing's syndrome is primarily caused by an excess of corticosteroids, particularly cortisol, in the body. This condition can develop from various sources, such as taking corticosteroid medications for other medical conditions or due to hypersecretion of cortisol from the adrenal glands, which may be influenced by tumors (either benign or malignant) in the pituitary gland or adrenal glands. The overproduction of corticosteroids leads to the characteristic symptoms and signs of Cushing's syndrome, including weight gain, easy bruising, high blood pressure, and changes in skin appearance.

The other options provided do not accurately represent the underlying cause of Cushing's syndrome. A lack of corticosteroids or reduced adrenal function would result in symptoms that are quite different from those seen in Cushing's syndrome, typically resembling adrenal insufficiency instead. An increase in thyroid hormones relates to thyroid disorders, such as hyperthyroidism, which is unrelated to Cushing’s syndrome. Understanding that the base pathology of Cushing's syndrome fundamentally revolves around excess production of corticosteroids helps clarify why this answer is correct.