Question:medium
Nelson syndrome is most likely seen after:
Nelson syndrome is most likely seen after:
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Loss of cortisol feedback unleashes a pituitary ACTH adenoma.
Updated On: Jun 24, 2026
- Hypophysectomy
- Adrenalectomy
- Thyroidectomy
- Orchidectomy
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The Correct Option is B
Solution and Explanation
Step 1: Nelson syndrome links a surgical event to a runaway corticotroph tumour. The trigger is taking out both adrenal glands, which was historically used to control Cushing disease driven by a pituitary adenoma.
Step 2: Logic of the feedback loop - cortisol normally suppresses the pituitary corticotrophs. Remove the adrenals and cortisol falls to zero, releasing the brake. ACTH output climbs steeply and the residual adenoma proliferates.
Step 3: The clinical signature is striking skin darkening (ACTH and its melanocyte-stimulating fragment) plus mass effects of an enlarging intrasellar tumour - headaches, bitemporal field loss and possible cavernous sinus extension. Prophylactic pituitary irradiation reduces the risk.
Step 4: Ruling out the rest - removing the pituitary (hypophysectomy) deletes the source tumour, while thyroidectomy and orchidectomy leave the cortisol-ACTH axis untouched.
\[\boxed{\text{Adrenalectomy}}\]
Step 2: Logic of the feedback loop - cortisol normally suppresses the pituitary corticotrophs. Remove the adrenals and cortisol falls to zero, releasing the brake. ACTH output climbs steeply and the residual adenoma proliferates.
Step 3: The clinical signature is striking skin darkening (ACTH and its melanocyte-stimulating fragment) plus mass effects of an enlarging intrasellar tumour - headaches, bitemporal field loss and possible cavernous sinus extension. Prophylactic pituitary irradiation reduces the risk.
Step 4: Ruling out the rest - removing the pituitary (hypophysectomy) deletes the source tumour, while thyroidectomy and orchidectomy leave the cortisol-ACTH axis untouched.
\[\boxed{\text{Adrenalectomy}}\]
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