HY USMLE Q#16 Endo Step 1 and Step 2CK

HY USMLE Q#16

Endocrinology (Step 1 and Step 2CK inspired from MEHLMAN instagram) 

A 45-year-old woman comes to Doctor for a follow-up. She has purple striae on a enlarged abdomen and marked peripheral wasting. She has a history of rheumatoid arthritis marked by numerous medications. Which of the following is seen in this patient?

 
A. Eosinophilia 
B. Increase serum potassium 
C. Metabolic acidosis 
D. Increase serum CRH 
E. Decrease serum cortisol

​

​

​

​

✅ Correct answer E = Decrease serum cortisol

Educational Objective:

This patient is taking exogenous cortisol. Hence, it will lead to low CRH, low ACTH, and low endogenous ( serum) cortisol.

​

❌ A. Patient is going to have low lymphocytes and eosinophils because cortisol will induce apoptosis of those cells. Additionally, cortisol can lead to impaired neutrophil migration to the surrounding tissue; consequently, more neutrophils accumulate in the blood vessels, resulting in neutrophilia.

​

❌ B. Cortisol can bind mineralcorticoid receptors, but normally, the enzyme 11 beta hydroxysteroid dehydrogenase  in the kidney inactivates cortisol to cortisone
At high pharmacological doses of exogenous cortisol, this enzyme can be overwhelmed, leading to mineralocorticoid effects and loss of potassium in the principal cells via the ROMK renal outer medullary potassium channel (ROMK).

​

❌ C. Cortisol can bind mineralcorticoid receptors, but normally, the enzyme 11 beta hydroxysteroid dehydrogenase  in the kidney inactivates cortisol to cortisone.
At high pharmacological doses of exogenous cortisol, this enzyme can be overwhelmed, leading to mineralocorticoid effects and loss of potassium in the principal cells via the ROMK renal outer medullary potassium channel (ROMK).

Corticosteroid excess overwhelms the enzyme 11 beta hydroxysteroid dehydrogenase in the kidney, inactivating cortisol to cortisone. This leads to the secretion of H+ ions from the alpha intercalated cells.

​

❌ D. Patient with exogenous cortisol will have low CRH and Low ACTH due to negative feedback.​​​​