Hypercalcemia Flashcards
define hypercalcemia
total serum calcium > 10.3 mg/dl, corrected for albumin
severe hypercalcemia
> 14 mg/dl
moderate/symptomatic hypercalcemia
> 12 mg/dl
90% of hypercalcemia in ambulatory patients is caused by
primary hyperparathyroidism
60-70% of hypercalcemia in hospitalized patients is caused by what
malignancy
20-30% of hypercalcemia in hospitalized patients is caused by
primary hyperparathyroidism
rare causes of hypercalcemia (4 listed)
- tertiary hyperparathyroidism. this arises in the setting of chronic kidney diz. CKD –> hyperphosphatemia/hypocalcemia –> secondary hyperparathyroidism –> “tertiary hyperparathyroidism”
- MEN1/MEN2A
- Granulomatis dz: Sarcoidosis/TB/Lymphoma –> increases 1,25-OH-dihydroxyvitamin D3
- familial hypocalciuric hypercalcemia
“serious” causes of hypercalcemia
lytic bone deposits, lung cancer, breast cancer, myeloma, lumphoma, primary tumors secreting PTHrP, head and neck squamous cell carcinoma, TB, sarcoid, pheocrhomocytoma, thyrotoxicosis, cholangiocarcinoma
When do you check calcium?
- hx of nephrolithiais (“blood in the urine..”)
- family hx of hypocalciuric hypercalcemia
- hydrochlorothiziade use
- lithium
- elderly pts with non-specific symptoms (apathy, irritability, memory loss etc)
diagnosis of hypercalcemia: first two steps
- Most cases due to primary hyperparathyroidism: measure intact PTH level
- If INTACT PTH normal or low–> measure PTHrP
unexplainated moderate to severe hypercalcemia
think malignancy, most common cause of significancly elevanted serum calcium levels
if PTH and PTHrP are low in the setting of hypercalcemia
measure 25-OH hydroxyvitamine D3