Infarction is a localized area of necrosis secondary to ischemia. Common sites of infarction include heart, brain, lungs, intestines, kidneys. Infarcts have multiple causes.
· Most infarcts (99%) result from thrombotic or embolic occlusion of an artery or vein.
· Less common causes include vasospasm and torsion of arteries and veins (e.g., volvulus, ovarian, and testicular torsion).
On gross examination infarctions typically have a wedge shape, with the apex of the wedge tending to point to the occlusion.
· Anemic infarcts (pale or white color) occur in solid organs with a single bloodsupply such as the spleen, kidney, and heart.
· Hemorrhagic infarcts (red color) occur in organs with a dual blood supplyor collateral circulation, such as the lung and intestines, and can also occur with venous occlusion (e.g., testicular torsion).
Microscopic pathology of infarction can show either coagulative necrosis (most organs) or liquifactive necrosis (brain). The general sequence of tissue changes after infarction is as follows: