The predominant cellular mechanism underlying glucocorticoid-induced osteoporosis is:

• A Direct suppression of osteoblast function and promotion of osteoblast apoptosis, with reduced intestinal calcium absorption ✓
• B Stimulation of osteoclast differentiation through RANKL overexpression alone
• C Secondary hyperparathyroidism driven by renal calcium wasting
• D Impaired vitamin D hydroxylation in adipose tissue

Explanation

Glucocorticoids directly reduce osteoblast replication and function, promote osteoblast and osteocyte apoptosis, increase osteoclast lifespan, and decrease intestinal calcium absorption with increased renal calcium excretion. The dominant early effect is suppression of bone formation rather than increased resorption, which is why bone loss is fastest in the first months of therapy and why bisphosphonates plus calcium and vitamin D are co-prescribed. Secondary hyperparathyroidism is not the principal driver, ruling out option C.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.