50 Calcium

Question 1

extracellular calcium concentrations are maintained within an
exquisitely narrow range through a series of feedback mechanisms that
involve

Answer 1

parathyroid hormone (PTH) and the active vitamin D metab-
olite 1,25-dihydroxyvitamin D [1,25(OH)2
D].

Question 2

Hypercalcemia associated
with granulomatous disease (e.g., sarcoidosis) or lymphomas is caused
by

Answer 2

enhanced conversion of 25(OH)D to the potent 1,25(OH)2

D

Question 3

The first step in the diagnostic evaluation of hyper- or hypocalcemia is
to ensure that the alteration in serum calcium levels is not due to

Answer 3

abnormal albumin concentrations