cns question - target99

[ArchivalUser]

58 yr old african american male presents to ER coz of sudden right side hand weakness
he has not snesory deficit
examintion shows intact cranial nerves and sensory functions
he has decreased strength is right hands only (3/5)
initail CT iwhtout contrast shows no abnormality
4 weeks later repeat brain imaging shows 9 mm lake like cavity lesion in left internal capsule
what is the cause of the patients conditions????

[ArchivalUser]

is it lacunar infarct ?

[ArchivalUser]

how did u get this
please explain

[ArchivalUser]

well if its right .....then only i can tell the way i thought for it !!! is it right ?

[ArchivalUser]

ofcourse its right
how to diffrentite between lacunar infarct and hypoxic encephalopathy in this q

[ArchivalUser]

lacunar infarct for target99

A quarter of all ischaemic strokes (a fifth of all strokes) are lacunar type.1 Lacunar infarcts are small infarcts (2“20 mm in diameter) in the deep cerebral white matter, basal ganglia, or pons, presumed to result from the occlusion of a single small perforating artery supplying the subcortical areas of the brain. Due to the size and specific oclussion of a small vessel the clinical findings are normally localized and very specific (llike in this case) and acute CT scan/MRI usually don't show abnormalities.

GL
Dode

[ArchivalUser]

well hypoxic encephalothy is more about generalised global dysfunction of CNS !!!
for this ques ......its kinda pure motor stroke like situation which r definately most common with lacunar infarcts !!!
secondaly only in infarct u will have cavity like lesions after few weeks , n these r due to infarction related liquifective necrosis which takes a time of few weeks to develop !!1
no cavity should develop in hypoxic encephalopathy , coz damage is never that severe n most imp cavity is developin in post limb area of intenal capsule , which is the territory for lacunar infarcts
hope wotever i have written is the right explanation

[ArchivalUser]

about your question cinical findings in hypoxic encephalopathy are broader not so specific as one hand without any other symptoms/signs. Than is the key here target99 the fact that the patient has findings of a stroke but clearly localized to a special area in the brain. I will give you all who read this an input. For neuroanatomy one of the most important questions to answer is location of the lesion, if you know the location you have the answer to the question. So whenever you have a case first think where is it located? based on that and the vignette you will be able to pick the right question. This is the golden rule for neurologists. First...localize.
GL
Dode

[ArchivalUser]

dodenuchi
can u sum up grosslyu which area you find what
actually im trying to sort that out only right now
plz help
hope im asking too mmuch

thanks himanshu

[ArchivalUser]

ok target99

I will use your example as a lecture (hahaha, just joking!)

First this patient complains of right hand weakness nothing else.
RHW can be caused by a cortical lesion, spinal or peripheral.

Let's start with peripheral lesion, could be at the plexus level (cervical compression), at the branch level (upper at the elbow/ulnar notch area or lower like carpal tunnel) Weakness, tingling, decrease in DTRs, sensory will be affected not this case

So now we move to spinal cord: weaknes can't be explained by CST (corticospinal tract) because this is extremely localized, remember they descend together.
Maybe this could involve dorsal columns (can't really explain weakness but I am using a "broad" approach); although also unlikely as the gracilis and cunetus are very close and unless you have a tiny lesion you will not be able to have such a localized lesion. Also there are not other findings (proprioception, sensory are intact)

Can't be lamina interna since the tracts are running together, you would have more clinical findings....so you are left with central lesion/cortical. Remember that since every area is well defined within the homunculus and perforating arteries supply specific areas, you could have a microinfarct/lacunar infarct and get this type of lesion without any other findings. Because you are affecting the cortex then you will have weakness (which is the only symptom) without any other findings. Furthermore, as himansu mentioned, you will need time to have findings (although you must remember that this is why they are telling you a CONTRAST CT scan (usually infarcts can be detected acutely with a contrast CT) Why you can't see this one? it is so tiny that you can't see small vessels and this is reported as "normal"

This is the best way to address the neuroanatomy. Know your tracts well, know where the lesion could be and once you practice enough you will be able to nail every single neuroanatomy case. So as soon as you read the chief complaint envision where is the lesion???? Then move from there.

GL
Dode