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Zorluk: OrtaEndocrinology and Metabolism

Match each of the following clinical and laboratory profiles with the most likely pathophysiologic diagnosis.

  • Low 8 AM serum cortisol, elevated plasma ACTH, hyperkalemia, and hyponatremiaPrimary adrenal insufficiency (Addison disease)
  • Low 8 AM serum cortisol, decreased plasma ACTH, normal potassium, and mild hyponatremiaSecondary adrenal insufficiency
  • Elevated 24-hour urine free cortisol, elevated plasma ACTH, and cortisol suppression with high-dose dexamethasonePituitary adenoma (Cushing disease)
  • Elevated 24-hour urine free cortisol, undetectable plasma ACTH, and no cortisol suppression with high-dose dexamethasoneCortisol-producing adrenal adenoma
  • Normal 8 AM serum cortisol, normal plasma ACTH, elevated plasma aldosterone, and suppressed plasma renin activityPrimary hyperaldosteronism (Conn syndrome)

Cevap

Each profile corresponds to a specific endocrine loop disturbance: Profile 1 to Primary adrenal insufficiency, Profile 2 to Secondary adrenal insufficiency, Profile 3 to Cushing disease, Profile 4 to Adrenal adenoma, and Profile 5 to Primary hyperaldosteronism.
Matching requires accurate identification of feedback loop disruptions. Primary defects show opposite directional changes in stimulating versus target hormones (e.g., high ACTH with low cortisol), whereas secondary defects show same-direction changes (e.g., low ACTH with low cortisol).

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1
Analyze profiles with low cortisol to distinguish the level of the defect.
Low cortisol with high ACTH and hyperkalemia indicates primary adrenal failure, while low cortisol with low ACTH and normal potassium indicates secondary (pituitary) failure.
The intact aldosterone response (normal potassium) in central adrenal insufficiency differentiates it from primary disease.
2
Analyze profiles with hypercortisolism to identify the specific Cushing syndrome etiology.
High ACTH that suppresses with high-dose dexamethasone points to Cushing disease (pituitary), while undetectable ACTH without suppression indicates a primary adrenal tumor.
Pituitary adenomas retain partial feedback sensitivity to high-dose steroids, unlike adrenal tumors or ectopic ACTH sources.
3
Evaluate the profile with isolated mineralocorticoid abnormalities.
High aldosterone with low renin and normal cortisol confirms primary hyperaldosteronism.
Autonomous aldosterone secretion suppresses renin via volume expansion and operates independently of ACTH and cortisol.

Anahtar Kavram

Diagnosis of adrenal disorders relies on interpreting hormone pairs (e.g., ACTH and Cortisol, Renin and Aldosterone) to distinguish primary adrenal pathology from central (pituitary) defects.
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Endocrinology and Metabolism

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