USMLE Forums banner
1 - 9 of 9 Posts

·
Registered
Joined
·
919 Posts
hmm.. what is yr CT for? a CT scan?

i didnt really understand the question. was it,

u wanna know the difference between a stroke and a transient ischemic attack? and that if there was a difference between the CT scans of both a stroke and TIA?

well TIA is a mini-stroke that resolves on its own hence transient. a stroke is a stroke which causes pathological consequences.
The risk of a stroke increases dramatically in the days and weeks after a transient ischemic attack, and the TIA may offer an opportunity to find a cause and prevent the permanent neurologic damage that results because of a stroke. also TIA resolves within 24 hrs if im not mistaken.
Within minutes, brain cells begin to die. There are two kinds of stroke. The more common kind, called ischemic stroke, is caused by a blood clot that blocks or plugs a blood vessel in the brain. The other kind, called hemorrhagic stroke, is caused by a blood vessel that breaks and bleeds into the brain.
so basically TIA are mini strokes that have blockages of vessels temporarily. but if they disappear within 24hrs then i dont think u can see it on the CT scan.. hmm actually im not sure about the CT scan part. anyone else?:confused:
 

·
Registered
Joined
·
247 Posts
Stroke and TIA have same mechanism : Occurs due to occlusion of carotid or vertebro-basilar artery ..... from thrombosis , embolism ...
1. difference is in time .. Symptoms of Stroke remain > 24 hours and dont resolve which occurs due to complete occlusion of arteries , S/S of TIA < 24 hours and resolve which occurs due to partial or decrease cerebral blood flow .......
2. Stroke caused by ischemia or hemorrhage , TIA almost always cause by ischemia ... as hemorrhage cant resolve with in 24 hours , but ischemia can resolve back if restore blood supply .....
3. Stroke mostly presents with focal deficit , TIA usually presents with transient vision loss ....
4. You cant differentiate both by CT with out contrast , as both are due to cerebeal ischemia ... but u have to do CT to rule out any hemorrhage in both cases to confirm your treatment regimen , if no blood , start treatment with aspirin ( > 3 hrs ) , tpa ( < 3 hours ) .......
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #4 ·
i ask what is the diffrience in deficit in TIA & stroke ? i mean do both have cerebral infarction ? and if yes why in TIA neurological deficit is clinically reversible although of already present lesion in CT ? does brain has reservoir for the unfarcted area ?:)
 

·
Registered
Joined
·
247 Posts
Variability in stroke recovery is influenced by collateral vessels, blood pressure, and the specific site and mechanism of vessel occlusion; if blood flow is restored prior to significant cell death, the pt may experience only transient symptoms, i.e., a TIA , if blood flow not restored causes significant cell death and develop stroke .... Its like Angina and infarction ....
Initially u cant tell its TIA or stroke ...... And we do CT to see mainly for hemorrhage whether its present or not .. to start treatment ......... For that reason we usually do CT without contrast coz to see blood u don need contrast .... In TIA or stroke in first few hours u usually see no significant change ... So just exclude hge , if not start Rx of ischemia .......
 

·
Registered
Joined
·
919 Posts
yes. when i was doing my attachment I was taught to differentiate the CT scans:

CT with hemorrhagic stroke will show a whitish lesion in the brain (because the blood clot is > dense than the brain tissue)

CT with ischemic or infarct will show hypodense area due to hypoxia in the particular infarct area. so CT with TIA and inchemic stroke will be same initially. but the main difference is TIA will resolve within 24 hrs because blood will continue to flow again and from being hypoxic, the area will again have blood supply.
 

·
Registered
Joined
·
187 Posts
As everybody knows, in CT hemorrhage is hyperdense, while ischemia is hypodense. This is invaluable knowledge for the exams.

However, I would like to underline that, in practice, within the first 24-48 hours nothing of the above may be evident, in either case. This is the reason why at this interval an additional CT is ordered. In this case, physicians search for cerebral edema surrounding the area that is supposed to be affected. This is the normal response of glia to neuronal tissue damage. What is more, this edema is usually responsible for the damage that follows the stroke; sometimes the primary lesion may be of minimal importance, but the compression phenomena caused by this secondary edema may be detrimental.

All these are irrelevant to TIA, of course, which, by definition, resolves within the first 24 hours without leaving trace (as other colleagues have beautifully described so far :)).

This post was to remind that things are rarely black & white in medicine, literally & metaphorically...:(
 
1 - 9 of 9 Posts
Top