Parathyroid

Question 1

functions of PTH in kidney

Answer 1

1. increases reabsorption of calcium

2. decreases reabsorption of phosphate

Question 2

familial hypocalciuric hypercalcemia (FHH): pathogenesis

Answer 2

defective calcium-sensing receptor (CaSR) on parathyroid cells –> PTH cannot be suppressed by an increase in calcium level –> mild hypercalcemia with normal to high PTH levels

Question 3

treatment of hypercalcemia (2) and how they work

Answer 3

1. furosemide (loop diuretic): augments calcium excretion

2. bisphosphanates: inhibit osteoclastic bone resorption

Question 4

medication used for severe hyperparathyroidism and its mechanism

Answer 4

cinacalcet: sensitizes CaSR in parathyroid gland to circulating Ca2+ –> decreased PTH

Question 5

dx: hypercalcemia and low PTH

Answer 5

PTH-independent hypercalcemia: cancer or granulomatous disease

Question 6

dx: hypocalcemia, high PTH, normal to low serum phosphorus

Answer 6

secondary hyperparathyroidism: vitamin D insufficiency, occult malabsorption, kidney failure

Question 7

dx: hypocalcemia, high PTH, high serum phosphorus (2)

Answer 7

pseudohypoparathyroidism (PTH resistance), renal insufficiency

Question 8

dx: hypocalcemia, low or normal PTH

Answer 8

hypoparathyroidism

Question 9

effects of FGF23 (2)

Answer 9

1. increases urinary phosphate excretion

2. decreases renal production of 1,25(OH)2D (active form of vitamin D)

Question 10

2 important causes of hypophosphatemia

Answer 10

IV glucose, catecholamines (epinephrine, dopamine, albuterol)

Question 11

vitamin D intoxication causes _____phosphatemia

Answer 11

hyper

Question 12

dx: positive Trousseau sign or Chvostek sign

Answer 12

hypoparathyroidism (hypocalcemic tetany)