Which of the following statements best describes the clinical difference between Cushing's disease and Cushing's syndrome?

Choice A rationale

Adrenal tumors represent only one specific cause of hypercortisolism. This statement is scientifically inaccurate because it fails to account for pituitary adenomas, ectopic ACTH production, or exogenous steroid administration. While adrenal adenomas or carcinomas can lead to Cushing's syndrome by autonomously secreting cortisol, they do not define Cushing's disease. Pathophysiologically, the term syndrome encompasses all etiologies of high cortisol, whereas the disease is specifically linked to the pituitary gland's overproduction of adrenocorticotropic hormone.

Choice B rationale

Cushing's disease is a specific subset of Cushing's syndrome caused by a pituitary adenoma secreting excess adrenocorticotropic hormone. This hormone stimulates the adrenal cortex to produce cortisol. Conversely, Cushing's syndrome is an umbrella term for any condition resulting in prolonged exposure to high cortisol levels, whether endogenous or exogenous. Common causes include long-term glucocorticoid therapy, adrenal tumors, or ectopic ACTH from small cell lung cancer. Normal serum cortisol ranges are 5 to 23 mcg/dL.

Choice C rationale

This choice incorrectly identifies the primary cause of Cushing's disease. Long-term glucocorticoid use is actually the most common cause of exogenous Cushing's syndrome, not the disease itself. Cushing's disease involves a primary internal pathology of the pituitary gland. Furthermore, claiming the syndrome is caused only by adrenal tumors is scientifically false, as it ignores the massive clinical population receiving therapeutic steroids for autoimmune or inflammatory conditions. The underlying molecular mechanism involves the disruption of the hypothalamic-pituitary-adrenal axis.

Choice D rationale

This statement reverses the clinical definitions and causes confusion regarding the terminology. Cushing's disease is never defined by external glucocorticoid administration; that is a hallmark of iatrogenic Cushing's syndrome. The disease refers specifically to the pituitary-driven process. While both involve high cortisol, the diagnostic differentiation is critical because treatment for the disease usually involves transsphenoidal surgery, while treatment for the syndrome depends entirely on the specific underlying trigger, such as tapering off prednisone or removing an adrenal mass.

Choice A rationale

Scheduling a CT scan is a diagnostic step used to identify adrenal adenomas or hyperplasia, which are common causes of primary hyperaldosteronism. However, in an acute presentation with a blood pressure of 220/135 mmHg, diagnostic imaging is not the immediate priority. The patient is experiencing a hypertensive crisis, which requires urgent physiological stabilization. While imaging is necessary for long-term treatment planning, the nurse must first address the life-threatening hemodynamic instability and electrolyte imbalances to prevent end-organ damage.

Choice B rationale

A low-sodium diet is a long-term management strategy for hyperaldosteronism to help control fluid retention and hypertension. However, in the presence of a hypertensive emergency, dietary modifications are insufficient and too slow to be effective. The patient requires immediate pharmacological intervention to lower blood pressure and prevent a cerebrovascular accident or myocardial infarction. Initial nursing actions must focus on acute interventions that produce rapid physiological changes rather than lifestyle or dietary adjustments that take days to manifest.

Choice C rationale

Monitoring for signs of fluid overload is the priority because aldosterone causes the kidneys to retain sodium and water while excreting potassium. Excess aldosterone leads to an expanded intravascular volume, contributing to the severe hypertension of 220/135 mmHg. The nurse must assess for peripheral edema, jugular venous distention, and pulmonary crackles. Managing volume status is critical to preventing heart failure and further escalation of the hypertensive crisis, making it the most vital assessment for a patient in this state.

Choice D rationale

Administering potassium supplements is necessary to correct the hypokalemia of 3.1 mEq/L, as the normal range is 3.5 to 5.0 mEq/L. However, potassium must be replaced with extreme caution in the setting of severe hypertension and potential renal impairment. While correcting the heart's electrical stability is important, the immediate threat to the patient's life is the extremely high blood pressure. Monitoring the systemic effects of the fluid and electrolyte imbalance takes precedence to guide safe administration of intravenous medications. .