<prompt> Hyperacute rejection occurs within:12 hours2 weeks1 month3 months  <response>: Ref. Robbins Pathology. 9th edition. Page. 233 Hyperacute RejectionThis form of rejection occurs within minutes or hours after transplantation.A hyperacutely rejecting kidney rapidly becomes cyanotic, mottled, and flaccid, and may excrete a mere few drops of bloody urine.Immunoglobulin and complement are deposited in the vessel wall, causing endothelial injury and fibrin-platelet thrombiGlomeruli undergo thrombotic occlusion of the capillaries, and fibrinoid necrosis occurs in arterial walls.The kidney cortex then under- goes outright necrosis infarction, and such nonfunctioning kidneys have to be removed. 