Endogenous Cushing syndrome vs Exogenous glucocorticoid effect
How to tell Endogenous Cushing syndrome and Exogenous glucocorticoid effect apart when a board question makes them look alike.
Endogenous Cushing makes cortisol internally; exogenous steroid use suppresses the axis from outside.
Side by side
Cushingoid features with autonomous cortisol excess, abnormal cortisol screening, and ACTH-dependent or adrenal source.
Cushingoid features in a patient taking glucocorticoids, with suppressed ACTH and suppressed endogenous cortisol production.
Pituitary, ectopic, or adrenal disease produces excess endogenous cortisol.
External glucocorticoid exposure suppresses CRH, ACTH, and adrenal cortisol synthesis.
Abnormal dexamethasone or late-night cortisol testing plus source localization supports endogenous Cushing syndrome.
Low ACTH and low endogenous cortisol in the setting of steroid use support exogenous glucocorticoid effect.
The trap
Both can look Cushingoid, so medication exposure and ACTH/cortisol pattern are decisive.
Watch it explained
The repair move
Ask whether cortisol is being produced internally or supplied externally before localizing the source.
Try a free question
CoreA patient on chronic prednisone has central weight gain, facial rounding, easy bruising, proximal weakness, low ACTH, and low endogenous cortisol. Which diagnosis best fits?
Show answer and explanation
Answer: B. Exogenous glucocorticoid effect. External steroid exposure suppresses ACTH and endogenous cortisol production.
Why the other choices are tempting
- A. Endogenous Cushing produces internal cortisol excess rather than suppressed endogenous cortisol from outside steroid use.
- C. Primary adrenal insufficiency causes low cortisol with high ACTH and often hyperkalemia.
- D. Pheochromocytoma causes episodic catecholamine symptoms.
- E. Metabolic syndrome lacks the medication-axis suppression pattern.
Flashcards
Tap a card to flip it.
What is the fastest separator for Endogenous Cushing syndrome vs Exogenous glucocorticoid effect?
Endogenous Cushing makes cortisol internally; exogenous steroid use suppresses the axis from outside.
What clue should make you choose Endogenous Cushing syndrome?
Cushingoid features with autonomous cortisol excess, abnormal cortisol screening, and ACTH-dependent or adrenal source.
Quick answers
What is the fastest way to tell Endogenous Cushing syndrome from Exogenous glucocorticoid effect?
Endogenous Cushing makes cortisol internally; exogenous steroid use suppresses the axis from outside.
What is the key clue for Endogenous Cushing syndrome?
Cushingoid features with autonomous cortisol excess, abnormal cortisol screening, and ACTH-dependent or adrenal source.
What is the key clue for Exogenous glucocorticoid effect?
Cushingoid features in a patient taking glucocorticoids, with suppressed ACTH and suppressed endogenous cortisol production.
What is the common trap with Endogenous Cushing syndrome vs Exogenous glucocorticoid effect?
Both can look Cushingoid, so medication exposure and ACTH/cortisol pattern are decisive.