OnlineMedEd: Nephrology - "Calcium"

Question 1

Explain the calcium sensor on PTH cells.

Answer 1

It is an inhibitory sensor, so when Ca is high it turns off the release of PTH.

Question 2

Osteo-__________ stimulate osteo-_________.

Answer 2

blasts; clasts

Question 3

Explain how PTH affects the bones and gut.

Answer 3

Causes increased release of Ca and Phos in the bones and increased Ca and Phos absorption in the gut.

Question 4

For every __________ change in albumin, increse the total calcium by 0.8.

Answer 4

1

Question 5

You need to replete Ca to avoid what dire complications?

Answer 5

Seizure

Arrhythmia

Question 6

Only treat hypercalcemia if _____________.

Answer 6

the person is symptomatic (bones, stones, moans, groans)

If they don’t, then recheck.

Question 7

How do you treat hypercalcemia?

Answer 7

• Fluids (helps dilute the calcium and flush the calcium from the kidneys)
• Bisphosphonates
• Calcitonin (immediate action for acute symptoms)

•Loop diuretics (only when they’re volume up)

Question 8

How do patients with hypercalcemia present?

Answer 8

• Bone pain
• GI pain
• AMS
• Kidney stones
• Pathologic fractures
• Brown tumors (osteitis fibrosis cystica)

Question 9

What three labs are diagnostic of hyperparathyroidism?

Answer 9

• High PTH
• High Ca
• Low Phos

Question 10

Differentiate primary, secondary, and tertiary hyperparathyroidism.

Answer 10

• Primary: single adenoma that secretes autonomously
• Secondary: appropriate physiologic response to low Ca or high Phos
• Tertiary: multiple autonomous adenomas

Question 11

Other than PTH, what lab can clue you into a diagnosis of hypercalcemia of malignancy?

Answer 11

High Phos

In HOM, the lesions release Ca and Phos from bone. The PTH is thus low and Phos continues to rise.

Question 12

What pattern of Ca, Phos, and PTH do you see in granulomatous hypercalcemia?

Answer 12

• High Ca
• High Phos
• Low PTH

Question 13

In a patient who has been _____________, the calcium can be elevated.

Answer 13

immobilized

Question 14

Give a differential for hypocalcemia.

Answer 14

• Hypoparathyroidism (iatrogenic 2/2 thyroidectomy or parathyroidectomy)
• Vitamin D deficiency
• CKD (secondary hyperparathyroidism)
• Pancreatitis (sequestration of Ca)

Question 15

Albright hereditary osteodystrophy is also called _________________.

Answer 15

pseudohypoparathyroidism

Defective PTH receptor leading to increased PTH but low Ca.

Question 16

How do you treat secondary hyperparathyroidism?

Answer 16

• Ca
• Vitamin D
• Cinacalcet