Hypercalcemia

Question 1

define hypercalcemia

Answer 1

total serum calcium > 10.3 mg/dl, corrected for albumin

Question 2

severe hypercalcemia

Answer 2

> 14 mg/dl

Question 3

moderate/symptomatic hypercalcemia

Answer 3

> 12 mg/dl

Question 4

90% of hypercalcemia in ambulatory patients is caused by

Answer 4

primary hyperparathyroidism

Question 5

60-70% of hypercalcemia in hospitalized patients is caused by what

Answer 5

malignancy

Question 6

20-30% of hypercalcemia in hospitalized patients is caused by

Answer 6

primary hyperparathyroidism

Question 7

rare causes of hypercalcemia (4 listed)

Answer 7

1. tertiary hyperparathyroidism. this arises in the setting of chronic kidney diz. CKD –> hyperphosphatemia/hypocalcemia –> secondary hyperparathyroidism –> “tertiary hyperparathyroidism”
2. MEN1/MEN2A
3. Granulomatis dz: Sarcoidosis/TB/Lymphoma –> increases 1,25-OH-dihydroxyvitamin D3
4. familial hypocalciuric hypercalcemia

Question 8

“serious” causes of hypercalcemia

Answer 8

lytic bone deposits, lung cancer, breast cancer, myeloma, lumphoma, primary tumors secreting PTHrP, head and neck squamous cell carcinoma, TB, sarcoid, pheocrhomocytoma, thyrotoxicosis, cholangiocarcinoma

Question 9

When do you check calcium?

Answer 9

1. hx of nephrolithiais (“blood in the urine..”)
2. family hx of hypocalciuric hypercalcemia
3. hydrochlorothiziade use
4. lithium
5. elderly pts with non-specific symptoms (apathy, irritability, memory loss etc)

Question 10

diagnosis of hypercalcemia: first two steps

Answer 10

1. Most cases due to primary hyperparathyroidism: measure intact PTH level
2. If INTACT PTH normal or low–> measure PTHrP

Question 11

unexplainated moderate to severe hypercalcemia

Answer 11

think malignancy, most common cause of significancly elevanted serum calcium levels

Question 12

if PTH and PTHrP are low in the setting of hypercalcemia

Answer 12

measure 25-OH hydroxyvitamine D3