Ischemic infarct vs Hemorrhagic infarct
How to tell Ischemic infarct and Hemorrhagic infarct apart when a board question makes them look alike.
Pale infarcts are arterial occlusion in dense end-arterial organs; hemorrhagic infarcts occur with venous occlusion, dual supply, loose tissue, or reperfusion.
Side by side
Ischemic pale infarcts occur in solid organs with end-arterial circulation such as heart, kidney, and spleen after arterial occlusion.
Hemorrhagic red infarcts occur with venous occlusion, loose tissues, dual blood supply, reperfusion injury, or previously congested tissues.
Arterial blockage in dense organs causes coagulative necrosis with little blood entry.
Blood enters necrotic tissue through collateral flow, reperfusion, venous congestion, or loose tissue spaces.
Wedge-shaped pale infarct in kidney or spleen supports ischemic infarct.
Red infarct in lung or bowel, torsion, venous thrombosis, or reperfusion supports hemorrhagic infarct.
The trap
Both result from compromised blood supply, but the color and morphology depend on the vessel type, the tissue architecture, and whether reperfusion or bleed-in occurred. PALE (anemic, white) infarct happens in solid end-arterial organs with TIGHT tissue and a single arterial supply (heart, kidney, spleen): when the artery occludes, blood cannot re-enter the dead tissue, so it stays pale (coagulative necrosis with preserved architecture for days, ghost outlines on H&E). RED (hemorrhagic) infarct happens in LOOSE tissue with DUAL or COLLATERAL blood supply (lung receives bronchial plus pulmonary circulation; liver receives portal plus hepatic artery; small intestine), or with VENOUS occlusion (testicular torsion, ovarian torsion, mesenteric venous thrombosis), or with REPERFUSION (after thrombolytic therapy or spontaneous lysis) where blood pours back into the damaged microvasculature. BRAIN infarcts are usually pale at first but can become hemorrhagic with reperfusion or anticoagulation.
The repair move
For infarcts, match vessel type and organ blood supply to pale versus red morphology.
Try a free question
CoreA 64-year-old man with hypertension and atrial fibrillation has sudden onset right hemiparesis. CT of the brain 24 hours later shows a well-demarcated pale (hypodense) wedge-shaped infarct in the left middle cerebral artery territory with no hemorrhage. Which type of infarct is this and what is the typical mechanism?
Show answer and explanation
Answer: A. Pale (anemic) infarct from arterial occlusion in a dense end-arterial organ. Pale infarcts occur in solid organs with limited collateral circulation (heart, kidney, spleen) after arterial occlusion; the brain typically shows pale infarct in dense end-arterial territory, although hemorrhagic conversion can occur after reperfusion.
Why the other choices are tempting
- B. Hemorrhagic infarcts occur in dual-blood-supply organs (lung, intestine) or after venous occlusion or reperfusion.
- C. Watershed infarcts are at junctions of arterial territories from hypoperfusion.
- D. Lacunar infarcts are small subcortical infarcts from small vessel lipohyalinosis.
- E. Septic infarcts have infected emboli (e.g., from endocarditis).
Flashcards
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What organs commonly get pale infarcts?
Heart, kidney, and spleen commonly get pale infarcts.
What setting supports hemorrhagic infarct?
Venous occlusion or reperfusion supports hemorrhagic infarct.
Quick answers
What is the fastest way to tell Ischemic infarct from Hemorrhagic infarct?
Pale infarcts are arterial occlusion in dense end-arterial organs; hemorrhagic infarcts occur with venous occlusion, dual supply, loose tissue, or reperfusion.
What is the key clue for Ischemic infarct?
Ischemic pale infarcts occur in solid organs with end-arterial circulation such as heart, kidney, and spleen after arterial occlusion.
What is the key clue for Hemorrhagic infarct?
Hemorrhagic red infarcts occur with venous occlusion, loose tissues, dual blood supply, reperfusion injury, or previously congested tissues.
What is the common trap with Ischemic infarct vs Hemorrhagic infarct?
Both result from compromised blood supply, but the color and morphology depend on the vessel type, the tissue architecture, and whether reperfusion or bleed-in occurred. PALE (anemic, white) infarct happens in solid end-arterial organs with TIGHT tissue and a single arterial supply (heart, kidney, spleen): when the artery occludes, blood cannot re-enter the dead tissue, so it stays pale (coagulative necrosis with preserved architecture for days, ghost outlines on H&E). RED (hemorrhagic) infarct happens in LOOSE tissue with DUAL or COLLATERAL blood supply (lung receives bronchial plus pulmonary circulation; liver receives portal plus hepatic artery; small intestine), or with VENOUS occlusion (testicular torsion, ovarian torsion, mesenteric venous thrombosis), or with REPERFUSION (after thrombolytic therapy or spontaneous lysis) where blood pours back into the damaged microvasculature. BRAIN infarcts are usually pale at first but can become hemorrhagic with reperfusion or anticoagulation.