Anemic infarct
Encyclopedia
Anemic infarcts are white or pale infarcts caused by arterial occlusions, and are usually seen in the heart, kidney and spleen. These are referred to as "white" because of the lack of hemorrhaging and limited red blood cells accumulation, (compare to Hemorrhagic infarct
). The tissues most likely to be affected are solid organs which limit the amount of hemorrhage that can seep into the area of ischemic necrosis from adjoining capillary beds. The organs typically include single blood supply (no dual arterial blood supply or anastomoses). The infarct generally results grossly in a wedge shaped area of necrosis with the apex closest to the occlusion and the base at the periphery of the organ. The margins will become better defined with time with a narrow rim of congestion attributable to inflammation at the edge of the lesion. Relatively few extravasated red cells are lysed so the resulting hemosiderosis
is limited and results in a progressively more pale area of infarction with time. Ischemic coagulative necrosis
results and fibrosis of the affected area develops from the reparative response beginning at the preserved margins and working its way inwards. One exception to coagulative necrosis is the brain, which undergoes liquefactive necrosis
in response to infarction.
Hemorrhagic infarct
Hemorrhagic infarcts are infarcts commonly caused by occlusion of veins, with red blood cells entering the area of the infarct, or an artery occlusion of an organ with collaterals or dual circulation. This is commonly seen in brain, lungs, liver and the GI tract, areas referred to as having "loose...
). The tissues most likely to be affected are solid organs which limit the amount of hemorrhage that can seep into the area of ischemic necrosis from adjoining capillary beds. The organs typically include single blood supply (no dual arterial blood supply or anastomoses). The infarct generally results grossly in a wedge shaped area of necrosis with the apex closest to the occlusion and the base at the periphery of the organ. The margins will become better defined with time with a narrow rim of congestion attributable to inflammation at the edge of the lesion. Relatively few extravasated red cells are lysed so the resulting hemosiderosis
Hemosiderosis
Idiopathic pulmonary haemosiderosis is a lung disease of unknown cause that is characterized by alveolar capillary bleeding and accumulation of haemosiderin in the lungs...
is limited and results in a progressively more pale area of infarction with time. Ischemic coagulative necrosis
Coagulative necrosis
Coagulative necrosis is a type of accidental cell death typically caused by ischemia or infarction.It is characterised by the 'ghostly' appearance of cells under light microscopy in the affected area of tissue. In coagulative necrosis the architecture of dead tissue is preserved for at least a...
results and fibrosis of the affected area develops from the reparative response beginning at the preserved margins and working its way inwards. One exception to coagulative necrosis is the brain, which undergoes liquefactive necrosis
Liquefactive necrosis
Liquefactive necrosis is a type of necrosis which results in a transformation of the tissue into a liquid viscous mass. Often it is associated with focal bacterial or fungal infections...
in response to infarction.