11 thoughts on “Q: What is the difference between red (hemorrhagic) and white (anemic) infarcts?”
When an infarct develops as a consequence of ischemia following complete or partial occlusion of an artery, secondary bleeding will occur from the surrounding veins (which anastomose between the areas supplied by other arteries).
When the infarct is a solid coagulation necrosis (e.g. as is seen in heart and kidney) this hemorrhage will stay at the edge of the infarct and it will appear pale (anemic) with a hemorrhagic border zone.
When the infarct is without a solid structure (e.g. lung, liver and brain) this secondary bleeding will flood the tissue and the infarct will appear red (hemorrhagic).
The morphologically different infarct types thus have a common pathogenesis.
I have to disagree.
Hemorrhagic infarcts occur in the bowel and the bowel is a pretty solid organ. The hemorrhage occurs when there are blood vessels in the affected area which are still supplied with blood, and is only the case when the organ or the specific area (eg watershed areas in the colon) has two arterial supplies.
The question should rather be: What is the patophysiological mechanism underlying red and pale infarcts, respectively?
Is it possible to generalize on this point: This mechanism leads to red infarcts and that mechanism leads to pale infarcts? Or should one rather take into account that the mechanism leading red/pale infarcts is unique in the specific organ and case where infarction occurs?
Can someone please comment on this?
I think that red/versus white infarct issue depends on the dual blood supply and the presence of “terminal arteries” providing the blood supply to a defined area without anastomoses. But it is also a “didactic simplification” and in real life many initially pale infarcts become at least “partially red” (e.g. myocardial or cerebral infarcts).This simplification is however clinically important in some cases, such as lung and intestine, because it results in bleeding (hemoptysis and hematochezia).I hope I did not confuse the entire class!
I was of the impression that the red marginal areas occuring in myocardial infarctions after af few days were caused by formation of granulation tissue. Am I wrong?
Ben, I hate to tell a colleage that your are wrong , but maybe it is good for the students to see that the professors do not agree among themselves.
I think that the “mottled appearance” of myocradial infarctions is quite common in the period between 3 and 7 days, well before the granulation tissue develops. My explanation is that the ischemia causes ischemic necrosis of capillaries in the infarcted area and and when the anastomoses (which form in most hearts, thus transforming the ‘terminal arteries” into “non-terminal arteries”) provide the blood it end is disrupted capillaries and hence the bleeding. Actually some of the best microscopic pictures I have taken are from hearts of persons who have died 5-7 days after the onset of infarction, because is their hearts you can see almost all the changes from early ischemia to complete necrosis, neutrophils and complete lysis of neutrophils( corresponding to pus formation). At the edges one may also see contraction band necrosis.
As an aside, I have been asked for legal purposes to “date infarcts” histologically. If you start reading the literature on that topic, most of it is more than 40 years old, and try to apply it to present day situation, you will discover for yourself how unreliable that “scientific approach” is.Infarcts often do not READ THE PATHOLOGY BOOKS, at least that is what I hve concluded at age 70!
My message for the students starting their studies of pathology: let’s keep it simple and talk about an idealized myocardial infarct which is classsifies as PALE infarct , and the type of necrosis is COAGULATIVE.
Hi weeven, you can read more about this in e.g. Robbins basic pathology, 9th edidtion page 92-93.
Briefly, white, pale, anaemic infarcts are seen in the spleen, kidney and the hearth. Red, hemorragic infarcts are seen in the long and the small intestines. In the brain you can see both white and red infarcts. Regarding infarcts in the liver, see this previous discussion on the blog: http://pathology.edublogs.org/2013/02/24/q-with-regards-to-liver-infarctions-are-they-red-or-white-or-both/
When an infarct develops as a consequence of ischemia following complete or partial occlusion of an artery, secondary bleeding will occur from the surrounding veins (which anastomose between the areas supplied by other arteries).
When the infarct is a solid coagulation necrosis (e.g. as is seen in heart and kidney) this hemorrhage will stay at the edge of the infarct and it will appear pale (anemic) with a hemorrhagic border zone.
When the infarct is without a solid structure (e.g. lung, liver and brain) this secondary bleeding will flood the tissue and the infarct will appear red (hemorrhagic).
The morphologically different infarct types thus have a common pathogenesis.
I have to disagree.
Hemorrhagic infarcts occur in the bowel and the bowel is a pretty solid organ. The hemorrhage occurs when there are blood vessels in the affected area which are still supplied with blood, and is only the case when the organ or the specific area (eg watershed areas in the colon) has two arterial supplies.
The question should rather be: What is the patophysiological mechanism underlying red and pale infarcts, respectively?
Is it possible to generalize on this point: This mechanism leads to red infarcts and that mechanism leads to pale infarcts? Or should one rather take into account that the mechanism leading red/pale infarcts is unique in the specific organ and case where infarction occurs?
Can someone please comment on this?
I think that red/versus white infarct issue depends on the dual blood supply and the presence of “terminal arteries” providing the blood supply to a defined area without anastomoses. But it is also a “didactic simplification” and in real life many initially pale infarcts become at least “partially red” (e.g. myocardial or cerebral infarcts).This simplification is however clinically important in some cases, such as lung and intestine, because it results in bleeding (hemoptysis and hematochezia).I hope I did not confuse the entire class!
I was of the impression that the red marginal areas occuring in myocardial infarctions after af few days were caused by formation of granulation tissue. Am I wrong?
Ben, I hate to tell a colleage that your are wrong , but maybe it is good for the students to see that the professors do not agree among themselves.
I think that the “mottled appearance” of myocradial infarctions is quite common in the period between 3 and 7 days, well before the granulation tissue develops. My explanation is that the ischemia causes ischemic necrosis of capillaries in the infarcted area and and when the anastomoses (which form in most hearts, thus transforming the ‘terminal arteries” into “non-terminal arteries”) provide the blood it end is disrupted capillaries and hence the bleeding. Actually some of the best microscopic pictures I have taken are from hearts of persons who have died 5-7 days after the onset of infarction, because is their hearts you can see almost all the changes from early ischemia to complete necrosis, neutrophils and complete lysis of neutrophils( corresponding to pus formation). At the edges one may also see contraction band necrosis.
As an aside, I have been asked for legal purposes to “date infarcts” histologically. If you start reading the literature on that topic, most of it is more than 40 years old, and try to apply it to present day situation, you will discover for yourself how unreliable that “scientific approach” is.Infarcts often do not READ THE PATHOLOGY BOOKS, at least that is what I hve concluded at age 70!
My message for the students starting their studies of pathology: let’s keep it simple and talk about an idealized myocardial infarct which is classsifies as PALE infarct , and the type of necrosis is COAGULATIVE.
But the question is: what are we supposed to answer to the exam, if we have to tell the difference red and white infarcts?
Etiological differences are pretty clear. But is there any morphological difference between red and pale infarcts?
how about the occurrence of red and white infarct?
Hi weeven, you can read more about this in e.g. Robbins basic pathology, 9th edidtion page 92-93.
Briefly, white, pale, anaemic infarcts are seen in the spleen, kidney and the hearth. Red, hemorragic infarcts are seen in the long and the small intestines. In the brain you can see both white and red infarcts. Regarding infarcts in the liver, see this previous discussion on the blog:
http://pathology.edublogs.org/2013/02/24/q-with-regards-to-liver-infarctions-are-they-red-or-white-or-both/
hi!
i have read that red infarct occurs when flows is re-establish to a site of previous arterial occlusion and necrosis. How to explain this?