cerebral infarcts: thrombotic vs. embolic

[MudPhud20XX]

Kaplan neuro explains:

1. thrombotic: anemic/pale infarct: usually atherosclerotic complication

2. embolic: hemorrhagic/red infarct: from heart or atherosclerotic plaques; middle cerebral artery most vulnerable to emboli

So can anyone explain the significance of the color pale vs red? What is the mechanism and how is different color related to the source of the infarct (thrombus vs embolus)?

Many thanks in advance.

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[notbobtrustme]

Thrombotic -> you have a plaque that ruptured, exposing subendothelial collagen, causing a thrombus to be formed. Even if you tPA or streptokinase, you won't be able to keep the clot busted for very long. Since there's no blood downstream, the tissue becomes pale.

Embolic -> a thrombotic (usually) embolus from the atria or from the lower extremity (if pt had a patent foramen ovale) breaks off and lodges into the arteries in the brain. This you can bust with tPA or streptokinase and since the surrounding endothelium is intact, the clot won't reform. This lets blood back into the tissue; however, the tissue behind the block will be damaged or dead, which leads to a hemorrhagic infarct rather than a pale infarct.

 

[Miracoli]

Stroke
A) Ischemic stroke
1. thrombotic: anemic/pale infarct:
2. embolic: hemorrhagic/red infarct:
B) Hemorrhagic stroke

 

[Apoplexy__]

Stroke
A) Ischemic stroke
1. thrombotic: anemic/pale infarct:
2. embolic: hemorrhagic/red infarct:
B) Hemorrhagic stroke

This is also very important to know. I tried discussing strokes with someone yesterday and they totally confused hemorrhagic infarcts (blockage of flow with later bleeding) with hemorrhagic strokes (hemorrhage is the primary pathology -- a rupture of a vessel).

To really reach the final/highest level of understanding with stroke pathology, you should compare all stroke pathologies' etiology+presentation. The UWorld questions will give you answers A through G or so of all the different stroke etiologies, where more than one answer is certainly not out of the question. You have to really pick out the details that delineate each etiology. It just so happens that the most similar pathologies can be differentiated on 3 key variables -- hemorrhagic vs. ischemic, intraparenchymal vessel vs. large vessel, and hypertension-related vs. non-hypertension-related. This is in contrast to the strokes whose presentation/etiology can be easily differentiated by one single tip-off (post-op stroke symptoms are going to be some hypoxic ischemic infarct; you're not thinking Amyloid Angiopathy).

I've attached a write-up I've made that walks through this. I know it's pretty tangential to your question, but I just really want to help you out because the understanding of stroke pathologies necessary for USMLE isn't in First Aid or Pathoma, and only in Robbins and UWorld. And even then, it's discussed bit by bit as opposed to all in one place.

Again, don't confuse ischemic strokes with hemorrhagic strokes (stroke due to burst vessel).

 

[ChessMaster3000]

This is also very important to know. I tried discussing strokes with someone yesterday and they totally confused hemorrhagic infarcts (blockage of flow with later bleeding) with hemorrhagic strokes (hemorrhage is the primary pathology -- a rupture of a vessel).

To really reach the final/highest level of understanding with stroke pathology, you should compare all stroke pathologies' etiology+presentation. The UWorld questions will give you answers A through G or so of all the different stroke etiologies, where more than one answer is certainly not out of the question. You have to really pick out the details that delineate each etiology. It just so happens that the most similar pathologies can be differentiated on 3 key variables -- hemorrhagic vs. ischemic, intraparenchymal vessel vs. large vessel, and hypertension-related vs. non-hypertension-related. This is in contrast to the strokes whose presentation/etiology can be easily differentiated by one single tip-off (post-op stroke symptoms are going to be some hypoxic ischemic infarct; you're not thinking Amyloid Angiopathy).

I've attached a write-up I've made that walks through this. I know it's pretty tangential to your question, but I just really want to help you out because the understanding of stroke pathologies necessary for USMLE isn't in First Aid or Pathoma, and only in Robbins and UWorld. And even then, it's discussed bit by bit as opposed to all in one place.

Again, don't confuse ischemic strokes with hemorrhagic strokes (stroke due to burst vessel).

great breakdown Kirby. I just wanted to add (or rather emphasize) that I think its really easy to confuse charcot-brouchard aneurysm rupture vs lacunar strokes. If you can remember that C-B are hemorrhagic and lacunar is not, a lot of stuff falls into place (at least for me).

 

[cnewber4]

This is also very important to know. I tried discussing strokes with someone yesterday and they totally confused hemorrhagic infarcts (blockage of flow with later bleeding) with hemorrhagic strokes (hemorrhage is the primary pathology -- a rupture of a vessel).

To really reach the final/highest level of understanding with stroke pathology, you should compare all stroke pathologies' etiology+presentation. The UWorld questions will give you answers A through G or so of all the different stroke etiologies, where more than one answer is certainly not out of the question. You have to really pick out the details that delineate each etiology. It just so happens that the most similar pathologies can be differentiated on 3 key variables -- hemorrhagic vs. ischemic, intraparenchymal vessel vs. large vessel, and hypertension-related vs. non-hypertension-related. This is in contrast to the strokes whose presentation/etiology can be easily differentiated by one single tip-off (post-op stroke symptoms are going to be some hypoxic ischemic infarct; you're not thinking Amyloid Angiopathy).

I've attached a write-up I've made that walks through this. I know it's pretty tangential to your question, but I just really want to help you out because the understanding of stroke pathologies necessary for USMLE isn't in First Aid or Pathoma, and only in Robbins and UWorld. And even then, it's discussed bit by bit as opposed to all in one place.

Again, don't confuse ischemic strokes with hemorrhagic strokes (stroke due to burst vessel).

Kibry, with a embolic stroke, will you see bright, hyper dense areas on CT in the beginning like in charcot buchard rupture. Will there be ischemia, then hemorrhage right after, or should we just think embolic as a hypo dense area like the rest of the ischemic strokes?

 

[Apoplexy__]

Kibry, with a embolic stroke, will you see bright, hyper dense areas on CT in the beginning like in charcot buchard rupture. Will there be ischemia, then hemorrhage right after, or should we just think embolic as a hypo dense area like the rest of the ischemic strokes?

I can only speak for UWorld/boards (not what your school might test on), but I've never seen embolic infarcts treated any differently than thrombotic. In other words, embolic = hypodense ischemia (this is how they're listed in my Word doc). You won't be given a CT with hyperdense areas and have "embolic infarct" be the answer.

I've never even seen evidence of having to know that embolic infarcts are eventually hemorrhagic, as Dr. Sattar of Pathoma seemed to think was important; I would almost put it in the back of your memory, outside of the discussion of strokes. I'm 90% sure his whole point with the discussion of embolic vs. thrombotic infarcts was to say that infarcts of the brain have a duality to them not necessarily seen in other tissues. Whereas in the lung and intestines you can say that coagulation necrosis is typically hemorrhagic and the kidney + liver is pale, one can add to the unusual characteristics of brain infarcts being liquefactive by saying that they can either be hemorrhagic or pale depending on the etiology.

 

[Fatalis]

This is also very important to know. I tried discussing strokes with someone yesterday and they totally confused hemorrhagic infarcts (blockage of flow with later bleeding) with hemorrhagic strokes (hemorrhage is the primary pathology -- a rupture of a vessel).

To really reach the final/highest level of understanding with stroke pathology, you should compare all stroke pathologies' etiology+presentation. The UWorld questions will give you answers A through G or so of all the different stroke etiologies, where more than one answer is certainly not out of the question. You have to really pick out the details that delineate each etiology. It just so happens that the most similar pathologies can be differentiated on 3 key variables -- hemorrhagic vs. ischemic, intraparenchymal vessel vs. large vessel, and hypertension-related vs. non-hypertension-related. This is in contrast to the strokes whose presentation/etiology can be easily differentiated by one single tip-off (post-op stroke symptoms are going to be some hypoxic ischemic infarct; you're not thinking Amyloid Angiopathy).

I've attached a write-up I've made that walks through this. I know it's pretty tangential to your question, but I just really want to help you out because the understanding of stroke pathologies necessary for USMLE isn't in First Aid or Pathoma, and only in Robbins and UWorld. And even then, it's discussed bit by bit as opposed to all in one place.

Again, don't confuse ischemic strokes with hemorrhagic strokes (stroke due to burst vessel).

Know this write up! Saved me a few times on the real deal! Annotate it into first aid!

 

[Apoplexy__]

Know this write up! Saved me a few times on the real deal! Annotate it into first aid!

Awesome to hear! Made my day. 🙂

 

[Fatalis]

Awesome to hear! Made my day. 🙂

literally during those questions I was like "thank god for kirbymiester's document!"

 

[EazyE1907]

Awesome to hear! Made my day. 🙂

Hey man. I think i'm a tad confused on the strokes. i read your word doc over and over. I most of it down. The only thing is, you say that Ischemic STROKES are delayed onset. So that would make lacunar INFARCTS rapid onset of focal neuro deficits? I'm having a hard time distinguishing lacunar infarcts from ischemic stroke. a uworld question states that occlusion via emboli causes lacunar infarcts, so how is that different from ischemic stroke if it will potentialy do the same thing. Is the main difference that lacunar INFARCTS effect small vessels and ischemic STROKES affect large ones (mca). i think i might be overthnking it.

 

[Apoplexy__]

Hey man. I think i'm a tad confused on the strokes. i read your word doc over and over. I most of it down. The only thing is, you say that Ischemic STROKES are delayed onset. So that would make lacunar INFARCTS rapid onset of focal neuro deficits? I'm having a hard time distinguishing lacunar infarcts from ischemic stroke. a uworld question states that occlusion via emboli causes lacunar infarcts, so how is that different from ischemic stroke if it will potentialy do the same thing. Is the main difference that lacunar INFARCTS effect small vessels and ischemic STROKES affect large ones (mca). i think i might be overthnking it.

Hey! I think this is the source of confusion:
Strokes = General term for lack of blood supply to neural tissue
Ischemic stroke = Infarct = Occlusion of vessel
Hemorrhagic stroke = Burst of vessel

In other words, strokes can be ischemic or they can be hemorrhagic. One or the other. Therefore, lacunar infarcts are a type of ischemic stroke; as such, they are delayed onset.

If it helps, I actually made a video based on the document I originally posted:

 

[EazyE1907]

Hey thanks for the reply. This is great and very helpful.

I see what your saying about lacunar infarct being a type of ischemic stroke. The uworld question id 22. gives a pt presenting with SUDDEN onset hand weakness. then mentions non-contrast ct w/o abnormalities. then he comes back 4 weeks later and the lacunar infarcts are there. So i get all that and had no probs with this question, other than the fact that the pt presented with SUDDEN focal neuro deficits, which contradicts the delayed onset of ischemic infarct. Maybe I'm just going overboard. If i get a similar question on the real deal i think i can figure it out based on the other clues. but just wondered why it said SUDDEN.

I appreciate the help. You are the man!

 

[Apoplexy__]

Hey thanks for the reply. This is great and very helpful.

I see what your saying about lacunar infarct being a type of ischemic stroke. The uworld question id 22. gives a pt presenting with SUDDEN onset hand weakness. then mentions non-contrast ct w/o abnormalities. then he comes back 4 weeks later and the lacunar infarcts are there. So i get all that and had no probs with this question, other than the fact that the pt presented with SUDDEN focal neuro deficits, which contradicts the delayed onset of ischemic infarct. Maybe I'm just going overboard. If i get a similar question on the real deal i think i can figure it out based on the other clues. but just wondered why it said SUDDEN.

I appreciate the help. You are the man!

Hm, yeah I suppose the interpretation of "sudden" is a bit subjective when just reading text in a question stem. I noted that paradigm from a combination of reading it in a text or two and then seeing how UWorld worded the vignettes. Hemorrhagic strokes may be worded as interrupting a patient's activities, or having a timeline of seconds. It's not to say that ischemic strokes aren't quick too (certainly not like subdural bleeds or something), but they're just maybe over the course of minutes. They seemed to word the hemorrhagic ones like the patient got hit by a bus or something: "patient was in the middle of a sentence and suddenly collapsed".

In other words, don't rely on the buzzword "sudden" to differentiate the two. It's a weak indicator, just something to support your developing thought. In the end, I'm just a student too...so the distinction could be clinically irrelevant haha.

And you're welcome! It makes me feel really good that people are finding this useful all these months later!

 

[EazyE1907]

Hm, yeah I suppose the interpretation of "sudden" is a bit subjective when just reading text in a question stem. I noted that paradigm from a combination of reading it in a text or two and then seeing how UWorld worded the vignettes. Hemorrhagic strokes may be worded as interrupting a patient's activities, or having a timeline of seconds. It's not to say that ischemic strokes aren't quick too (certainly not like subdural bleeds or something), but they're just maybe over the course of minutes. They seemed to word the hemorrhagic ones like the patient got hit by a bus or something: "patient was in the middle of a sentence and suddenly collapsed".

In other words, don't rely on the buzzword "sudden" to differentiate the two. It's a weak indicator, just something to support your developing thought. In the end, I'm just a student too...so the distinction could be clinically irrelevant haha.

And you're welcome! It makes me feel really good that people are finding this useful all these months later!

Yea. Makes a lot of sense man. I'll stick to the word doc and not get caught up on the tiny detail of sudden, unless there's absolutely no other clue, but that's highly unlikely with this type of question.

Thanks again!

 

[notbobtrustme]

Hey thanks for the reply. This is great and very helpful.

I see what your saying about lacunar infarct being a type of ischemic stroke. The uworld question id 22. gives a pt presenting with SUDDEN onset hand weakness. then mentions non-contrast ct w/o abnormalities. then he comes back 4 weeks later and the lacunar infarcts are there. So i get all that and had no probs with this question, other than the fact that the pt presented with SUDDEN focal neuro deficits, which contradicts the delayed onset of ischemic infarct. Maybe I'm just going overboard. If i get a similar question on the real deal i think i can figure it out based on the other clues. but just wondered why it said SUDDEN.

I appreciate the help. You are the man!

Sudden means within 15 minutes to 24 hrs which is consistent with either hemorrhagic or embolic stroke. Gradual is days to weeks to months (eg vascular dementia, Alzheimer's, prion diseases, brain tumors).