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A 61-year-old man with chronic renal failure (CRF) is being considered for a renal transplant. His serum calcium level is 7.6 mg/dL. Which of the following findings is most likely present?
A. Bilateral adrenal hyperplasia
B. Enlargement of all four parathyroid glands
C. Functional parathyroid adenoma
D. Hyperplasia of the anterior pituitary gland
E. Hyperplasia of the thyroid follicular cells
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losing Ca, PTH increase, PT hyperplasia
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Actually I answered E , becuase stimulation of chief cells , but you guys are good .....
Option B (Enlargement of all four parathyroid glands) is correct. The patient has CRF, which causes retention of phosphorus and hypovitaminosis D due to loss of the 1-α-hydroxylase enzyme in the proximal tubules. Hypovitaminosis D causes hypocalcemia, which stimulates all four parathyroid glands to synthesize parathyroid hormone (PTH). This compensatory increase in PTH is called secondary hyperparathyroidism. The glands are enlarged due to hyperplasia of the chief cells. Excess phosphorus contributes to hypocalcemia by driving calcium into tissues (called metastatic calcification) and, along with hypocalcemia, stimulates the parathyroid glands to synthesize more PTH.
