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Medicine

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Endocrine

Question
6 out of 16
 

Which of the following is a cause of secondary hyperparathyroidism?



A Rickets
B CRF

C Malnutrition
D All of the above

Ans. D

All of the above

Hyperparathyroidism (Ref: Hari-18th ed., Pg-3110)

Causes

1). Primary hyperparathyroidism

Ca, PO4, PTH

a. The most common cause of primary hyperparathyroidism is parathyroid solitary adenoma.

b. “A single solitary abnormal gland is the cause of approximately 80% of patients”

c. The abnormality of the gland is usually a benign neoplasm or adenoma and rarely a parathyroid carcinoma.

Important Point

a. Adenomas are most often located in the inferior parathyroid glandq.

b. Chief cells are predominant in both hyperplasia and adenoma.

2). Secondary hyperparathyroidism: Ca2+, PTH (MCQ) PO4

Causes Low vitamin D intake, chronic renal failure, Rickets, osteomalacia, malabsorption (FAQ)

The "trade-off hypothesis" for Ca2+/PO42–homeostasis with progressively declining renal function.

(Ref. Hari -18th ed. Pg-2289)

In CRF, serum calcium level decreases and serum phosphate level increases.

3). Tertiary hyperparathyroidism: Ca2+, PTH (FAQ) PO4

Occurs after prolonged secondary hyperparathyroidism, causing glands to act autonomously having undergone hyperplastic or adenomatous change.

This causes Ca2+ from secretion of PTH unlimited by feedback control. Seen in chronic renal failure.

4). Malignant hyperparathyroidism

Causes: Parathyroid-related protein (PTHrp) is produced by some squamous cell lung cancers, breast and renal cell carcinomas. (FAQ)

Extra Edge: Hypercalcemia in malignancy occur due to increase level of PTHrp. In this PTH level are not raised (AIIMS Nov 09).

Endocrine Flashcard List

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