A 24-year-old woman with long-standing anorexia nervosa (restricting type) is diagnosed with osteoporosis on DEXA scan with a T-score of -2.8 at the lumbar spine. Which of the following is the most important underlying mechanism for bone loss in anorexia nervosa?
- A Hypercortisolemia
- B Vitamin D deficiency
- C Hypoestrogenism ✓
- D Hyperthyroidism
Correct answer: C. Hypoestrogenism
Explanation
The primary mechanism for osteoporosis in anorexia nervosa is hypoestrogenism secondary to hypothalamic amenorrhea and functional suppression of the hypothalamic-pituitary-gonadal axis. Estrogen deficiency leads to increased bone resorption. While hypercortisolemia, vitamin D deficiency, and nutritional factors contribute, estrogen deficiency is considered the central pathogenic factor. Weight restoration and return of menses are the most effective interventions for bone recovery.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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