Parathyroid

Question 1

What is the function of parathyroid hormone?

Answer 1

Increase plasma calcium

Question 2

What is the target tissue of PTH?

Answer 2

Bone, intestine, kidneys

Question 3

How does PTH affect bone?

Answer 3

Releases calcium and phosphate
Stimulates osteoclasts

Question 4

How does PTH affect the kidneys?

Answer 4

Stimulates calcium resorption
Stimulates phosphate and bicarbonate excretion
Stimulates conversion of inactive Vitamin D into calcitriol (active vitamin D)

Question 5

How does PTH affect the GI/intestines?

Answer 5

Indirectly stimulates calcium and phosphate absorption in the intestines
Calcitriol stimulates intestines to absorb Ca/PO4

Question 6

What stimulates PTH?

Answer 6

Small decrease in plasma calcium

Question 7

What inhibits PTH?

Answer 7

Increase in plasma calcium

Question 8

What are causes of hyperparathyroidism? Which is more common?

Answer 8

Adenomas (most common cause)
Hyperplasia of 2+ parathyroid glands

Question 9

What are common lab findings of hyperparathyroidism?

Answer 9

Hypercalcemia
Hypercalciuria
Hypophosphatemia
Metabolic acidosis

Question 10

What are S/S of hyperparathyroidism?

Answer 10

Kidney stones
Osteoporosis
Weakness, lethargy
Polyuria, nocturia, polydipsia

Question 11

What causes hypoparathyroidism?

Answer 11

Surgical removal or damage of parathyroids

Question 12

What are S/S of hypoparathyroidism

Answer 12

Muscle spasms, tetany, neuromuscular excitability, pruritis

Question 13

What are lab findings of hypoparathyroidism?

Answer 13

Hypocalcemia
EKG arrhythmias
Hyperphosphatemia
Chvostek’s sign