Calcium homeostasis is normally under very tight control! There are 3 main sites of control: the gastrointestinal tract, bone, and kidney.
Hypercalcemia can happen for a variety of reasons (Multiple myeloma, cancer, Sarcoidosis, hyperparathyroidism, Milk-alkali syndrome, vitamin D intoxication etc.)
Subsequently acute renal failure may develop in the context of this pathology for several reasons.
Polyuria during the hypercalcemia may cause hypovolemia and pre-renal AKI.
Vaso-constrictive effects of calcium. An increased influx of calcium into the vascular smooth muscle cells leads to an augmented muscular tone. Therefore increased vascular resistance and reduced renal perfusion.
Hypercalcemic nephrolithiasis. Formation of Ca2+-Oxalate stones, potentially causing obstruction and renal insufficiency.
Moysés-Neto M et al. Acute renal failure and hypercalcemia. Ren Fail. 2006;28(2):153-9.
Simonetti G. Calcium and blood pressure. Ther Umsch. 2007 May;64(5):249-52.
Carroll MF, Schade DS. A practical approach to hypercalcemia. Am Fam Physician. 2003 May 1;67(9):1959-66.
Parks J, Coe F, Favus M. Hyperparathyroidism in Nephrolithiasis. Arch Intern Med. 1980;140(11):1479-1481.