Stroke and Intracranial Hemorrhage (5Q) Flashcards
Transient ischemic attack: Pt.
Patient at risk for embolization due to cardiac (A-fib, rheumatic heart disease, mitral valve disease, endocarditis, mural thrombi in MI, ASD), vascular disease (esp in brain, carotid bifurcation- bruits), AIDS. Older patients.
subclavian steal syndrome
localized stenosis or occlusion of one subclavian artery proximal to the source of the vertebral artery (blood is stolen) from artery). Causes ischemia.
TIA: Hx/Px
Acute onset changes in mental status, focal weakness (similar to stroke) that are recovered rapidly (in minutes). Rarely causes loss of consciousness or acute confusion. Increases risk of stroke.
Who is at the highest stroke risk?
Pts > 60yo, those with diabetes, or after TIA lasting longer than 10 minutes, and with symptoms or signs of weakness, speech impairment, or gait disturbance.
TIA: Imaging
CT or MRI within 24 hours of attack is indicated to exclude the possibility of small cerebral hemorrhage or cerebral tumor.
Next: MR or CT angiography to visualize any stenosis of cervical vasculature.
Carotid duplex US is useful for visualizing stenosis of internal carotid. May also do Echocardiogram to see if source can be identified.
GS is conventional arteriography (if others reveal nothing)
TIA: Labs
Assess for hematologic disorders (CBC, homocysteine), heart disease (lipids), diabetes (blood glucose) and serologic tests for syphillis.
Also get EKG, BP
TIA: medical
Obv. use meds to prevent future attacks by reducing risk (HTN, lipids, DM).
Medical anti-coagulation is initiated in patients who are poor surgical candidates or have widespread vascular disease or have evidence embolization from heart.
Tx is anti-coagulants: tissue plasminogen activator (tPA)
ABCD score:
establishes risk of TIA occurance: Age over 60- 1
BP > 140/90- 1
Clinical Sx of focal weakness- 2 points OR speech impairment without weakness (1)
duration >60 mins = 2, 10-59 mins (1), DM=1
ABCD > 3 should be admitted.
How to manage a thrombus in the heart
to prevent stroke, give anticoagulants (tPA) to break up clot. Don’t worry about hemhorrage, risk of another embolus is much higher.
How to medically prevent non-cardioembolic attacks
low-dose aspirin should be given to prevent future attacks. If attacks are refractory to aspirin, then add dipyridamole (PDE inhibitor).
clopidogrel can be used for Pts who cannot tolerate aspirin
When is surgery indicated in TIA?
when arteriography reveals an accessible high-grade stenosis (70-99% occlusion) on the appropriate side and there is relatively little atherosclerosis elesewhere in the cerebrovascular system. Not indicated for stenosis <50%.
Lacunar infarction
small lesions <5mm that occur in the distribution of the short penetrating arterioles in the basal ganglia, pons, cerebellum, internal capsule, thalamus, an deep cerebral white matter.
Present as contralateral pure motor or pure sensory deficit, ipsilateral crural (mild) paresis, and dysarthria + clumsiness of hand.
Clinical evaluation of suspected stroke or TIA should always include (in PE):
examination of heart and auscultation over subclavian and carotid vessels.
Occlusion of anterior cerebral artery:
Only causes sx if distal to junction with anterior communicating artery.
Sx: weakness and cortical sensory loss in the contralateral leg (loss of proprioception) and maybe mild proximal arm weakness.
Urinary incontinence is UNCOMMON. Bilateral infarcts will cause behavior change.
Occlusion of middle cerebral artery:
Sx: Contralateral hemiplegia, hemisensory loss, homonymous hemianopsia w/ eyes deviated toward side of lesion.
If dominant hemisphere is involved, there will be global aphasia.
More distal infarcts cause more limited Sx.
Occlusion of the posterior cerebral artery:
thalamic syndrome- contralateral hemisensory disturbance occurs followed by spontaneous pain and hyperpathia. Macula-sparing homonymous hemianopsia.
Occlusion of vertebral artery:
depends on location and extent of collateral circulation. Silent if good. If poor- then coma with pinpoint pupils, flaccid quadriplegia, sensory loss, cranial nerve abnormalities.
Occlusion of the posterior inferior cerebellar artery (PICA)
ipsilateral spinothalamic sensory loss involving the face, IX and X CN lesions, limb ataxia/numbness, and Horner syndrome
+contralateral spinothalamic sensory loss of limbs
Quick review: fine touch, vibration, 2 pt discrimination, and proprioception are carried by with sensory pathway? Where does it decussate?
Posterior column-medial lemniscus pathway. Decussates at level of brainstem.
Quick review: nociception and temperature are carried by which sensory pathway? Where does it decussate?
Spinothalamic pathway. Decussates at spinal cord, a few levels above root.
What is the name of the pathway that carries motor information from the brain?
pyramidal tracts (corticospinal + corticobulbar tracts)
Occlusion of basilar artery (or both vertebral arteries):
coma with pinpoint pupils, flaccid quadriplegia, sensory loss, and variable cranial nerve anomolies.
If partially occluded: diplopia, visual loss, vertigo, dysarthria, ataxia, weakness, sensory loss in some limbs or discrete CN palsies.
Occlusion of a major cerebellar artery:
vertigo, nausea, vomiting, nystagmus, ipsilateral limb ataxia, contralateral spinothalamic sensory loss.
When does coma occur in stroke?
Either due to infarction of carotid or vertebrobasilar artery, or due to compression of brainstem after cerebellar infarct.
