JC25 (Medicine) - Stroke Flashcards
Define stroke
Rapid onset
Focal or global disturbances of cerebral functions
due to non-traumatic vascular causes
Symptoms lasting >24 hours or leading to death
Stroke vs TIA
Difference?
Stroke = permanent neurological dysfunction/ impairment + imaging evidence of ischemia/ infarct
TIA: Focal neurological symptoms <24 hour without evidence of permanent neurological impairment or acute infarct
3 major types of stroke, prevalence
1) Ischemic stroke (75-80%): cortical, subcortical, posterior circulation, lacunar
2) Intracerebral hemorrhage (20%): Supratentorial, Infratentorial
3) Subarachnoid hemorrhage (<5%)
Mortality rate (in one year) of 3 major types of stroke
Subarachnoid hemorrhage (50%) Intracerebral hemorrhage (50%) Ischemic stroke - cortical (35%) Lacunar infarct (rare)
Causes of ischemic stroke
Ischemia:
1) Thrombosis
- Large vessel: atherosclerosis, arterial dissection, arterial vasospasm, fibromuscular dysplasia, moya moya disease, hyper-coagulability
- Small vessel: lipohyalinosis, athersclerosis
2) Embolism - clot fragment from heart or proximal vessels causing infarct, cardioembolic or non- cardioembolic stroke
3) Hypoxia - Poor cerebral perfusion causing border zone/ watershed area infarcts, no vascular occlusion
- Hypotension, diffuse athersclerosis
Common sites of carotid artery occlusion (5)
1) Atheroma +/- clot at bifurcation of common carotid artery into external and internal c.a. (most common)
2) Dissecting aneurysm of ICA below base of skull
3) Atheroma +/- clot at bifurcation of ICA into Anterior and middle c.a.
4) At siphon within cavernous sinus
5) Root of Common c.a. from brachiocephalic trunk or aorta (rare)
Causes of hemorrhagic stroke
Intracerebral hemorrhage
- hypertension
- Cerebral amyloid angiopathy
- Trauma
- Bleeding tendency
- AVM
- Aneurysm
- Brain tumor bleeding
- Cerebral venous thrombosis
- Hemorrhagic transformation
- Moya Moya
Subarachnoid hemorrhage:
- Trauma
- Berry aneurysm rupture
- Peri- mesencephalic non- aneurysmal SAH
causes of subarachnoid hemorrhage
Most common cause is spontaneous rupture of Saccular/ Berry aneurysms
Other causes:
Cerebral Vascular malformation, dural AV fistula
Transmural cerebral arterial dissection
Traumatic brain injury
Coagulopathies and bleeding tnedencies
Early vs Late presentation of Moyamoya disease?
Early: Ischemic symptoms due to progressive occlusion of c.a.
Late: Hemorrhagic symptoms due to fragile collateral vessels
Risk factors of stroke
Unmodifiable:
Old age
Male sex
History of TIA or stroke
Peripheral vascular disaease
6 cardiac causes of cerebral emboli
Mitral stenosis - mural and valvular thrombi
Subacute bacterial IE - vegetation, septic emboli
Valve replacement - thrombi
MI - mural thrombi
Ventricular aneurysm with intraluminal clot
Congestive HF, A-fib ***
Distribution of congenital cerebral anurysms that cause SAH?
Anterior circulation = 85%
- Anterior cerebral, middle cerebral and internal carotid artery and branches
Posterior circulation = 15%
- PCA, Basilar, vertebral and PICA
Clinical ddx of stroke?
MINT
Metabolic: hypoglycemia, hyperglycemia, Wernickes encephalopathy, Hypertensive encephalopathy, Hypoxia and hypercarbia
- check ABG, Glucose, O2 saturation, LFT, BP
infection
- CNS abscess and meningoencephalitis
- Bells palsy (HSV)
- Vestibular neuronitis
Check CBC with WBC differential
Neurological:
- Seizure with Todd’s paresis
- Brain tumor
- Traumatic brain injury
- Migraine with aura
- MS
- Conversion disorder
Check EEG, MRI, LP
Toxins - check toxicology screen and blood alcohol levels
Chorea and hemiballismus: typical location of lesion?
Chorea and hemiballismus: subthalamic nucleus
Acute occlusion of ICA leads to which neurological symptoms
Frontal lobe, parietal lobe and eye:
Hemiparesis +/- hemifacial weakness
Hemisensory loss
Visuospatial disorientation
Language disturbance (Parietal and Frontal)
Visual disturbance (Retinal stroke or amaurosis fugax)
Dysarthria and dysphagia (rare, bilateral innervation can typically compensate)