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STROKE (Clinical manifestations (post circ infarcts: Cerebellar symptoms…
STROKE
Clinical manifestations
post circ infarcts: Cerebellar symptoms and signs; Cranial nerve palsies; Motor and sensory symptoms and signs
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Crossed signs (ipsilateral cranial nerve palsy and contralateral hemiparesis) (? use combination of signs to locate site?)
infarct in internal capsule, pyramidal tract--> motor responses....
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parietal--> hemihypoesthesia, speech, identifying ppl and structures
temporal--> auditory, wernicke, memory,...
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Classification (in acute phase, hemorrhagic worse than ischemic; in chro
Ischemic: 88%
Types
Hypoperfusion: ex MI, CHF, toxicity causing sudden decr in BP, internal or external major bleeding (trauma), cardiovascular surgery,..
Embolic:
- Second most common cause of stroke
- Causes:
- Majority of emboli originate in heart, w/ plaque breaking off from endocardium
- (u. in atherosclerotic setting): artery to artery: thrombosis in an artery (ex basilar) -> goes to PCA
- manifests:
- u during activity (NOT in sleep)
- SUDDEN, RAPID occurrence of severe clinical symptoms
- u no TIA
- u remains CONSCIOUS although may have a headache
- Recurrence common unless underlying cause aggressively treated
Thrombotic
- 2/3 a. w/ HTN and diabetes
- Cause:
- Large extracranial vessels
- atherosclerosis
- dissection
- Takayasu
- GCA
- fibromuscular dysplasia
- Large intracranical vessels
- " "
- " "
- arteritis/vasculitis
- noninfl vasculopathy
- Moyamoya syndrome
- vasoconstriction
- Small vessel disease
- lipohyallinosis (due to HTN) and fibrinoid degeneration
- manifests:
- u. during SLEEP (bc of autonomic changes)
- u. SLOW evolution of symptoms over a few hrs
- often preceded/proceeds by TIA
Signs and Symps:
- Most DO NOT have decr level of consciousness in first 24 hrs EXCEPT when
- brain stem problem from upper 1/3 of pons and higher (ARAS)
- ischemia on one side and previous problem on other
- global ischemia
- thrombosis of int carotid or basilar
- arterial anastomoses to other side
- sudden obstruction of MCA before giving of deep, ant, superf branches
- Symptoms often worsen during first 72 hrs due to cerebral edema: vasogenic edema + cellular (more prominent) edema--> incr ICP--> herniation + decr consciousness + even death
Recurrence and Death after initial ischemic stroke
- Recurrence: 2% at 7 days, 4% at 30 days,12% at 1 yr, and 29% at 5 yrs
- Death: 7% at 7 days, 14% at 30 days, 27% at 1 yr, and 53% at 5 yrs
Dx: CT (may not show ischemia up to 72 hrs); for ddx of stroke: ABG, CBC, vital signs control, MRI,...
Hemorrhagic: 12%
Types
Subarachnoid:
- Causes:
- Most common: rupture of saccular or Berry aneurysms; (most important in aneurysms: discovering them; many pxs have warning signs; may have had headaches a few days or weeks prior to rupture. most common and worst prognosis: aneurysm of ant communicating)
- Others: arteriovenous malformations ( <30 yrs, AVM more common than aneurysm), angiomas, mycotic aneurysmal rupture (related to systemic endocarditis) etc.
- manifests:
- charac: Acute, severe headache (worst headache of px’s life), and meningismus (neck rigidity not seen <12hrs)
- if hemorrhage only in subarachnoid space--> not much neural deficits
- dx:
- CT: blood in basal cisterns in first 12 hrs after SAH w/ 95% sensitivity and specificity; hemorrhagic sites hyperdense in CT
- If no blood seen on CT
- non invasive: CT angio or MRA
- if headache w/ serious signs such as neck rigidity--> LP to confirm or r/o dx of SAH.
- prognosis: aneurysm rupture--> primary: 80%, secondary: 95%
Intracerebral:
- Causes: small arteries damaged--> vessel wall disrupted--> leakage
- HTN common + most important (most common places: Basal ganglia (and adjacent int. Capsule), Lobar (deep white matter), Cerebellum, Brain stem)
- Cerebral amyloid angiopathy (genetic or secondary to other diseases)
- manifests:
- Commonly during activity (NOT during sleep)
- Often: sudden onset of symptoms that progress over mins to hrs during ongoing bleeding
- NEUROLOGIC DEFICITS, headache, nausea/ VOMITING, DECR levels of CONSCIOUSNESS, and HTN (u > 200)
Patho:
- in ACUTE phase, hemorrhagic WORSE than ischemic bc:
- Explosive entry of blood --> neural dysfunction (neurons structurally disrupted) + incr ICP + herniation when severe (Large hemorrhages--> transtentorial coning + rapid death)
- expands esp in first 6 hrs (Expanding hemorrhage act as a mass lesion--> further progression of neurological deficits)
- in CHRONIC phase, hemorrhagic BETTER than ischemic bc:
- hematoma absorbed
- damage less than ischemia (if px passes first 2 ws of acute phase in hemorrhagic, prognosis generally better than ischemic)
RFs
Nonmodifiable
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Gender (Women slightly less likely to have a stroke than men of same age. But women have strokes at a later age--> worse prognosis)
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Modifiable
vascular
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Asymptomatic carotid stenosis (a predictor; screenin w/ doppler only in DM and sometimes young ppl w/ MI & stroke)
Endocrine: Diabetes mellitus, OCP
Cardiac: Heart disease, atrial fibrillation, CHF, CAD
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Lifestyle: Physical inactivity, obstructive sleep apnea, Heavy alcohol consumption
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Patho:
ischemia (inadequate blood flow)
- Neurologic metabolism altered in 30 s
- Metabolism stops in 2 min
- Cell death occurs in 5 min
border zone of reduced blood flow: ischemia potentially reversible; If adequate blood flow restored early (<3 hrs)--> less brain damage and less neurologic function lost
Definition: Rapidly developing clinical signs of focal (or global) disturbance of cerebral function, w/ symptoms lasting 24 hrs or longer w/ no apparent cause other than of vascular origin
Brain circulation:
ant: internal carotids
post: vertebral / basilar arteries
The two systems connect at Circle of Willis
Epid:
15 mill/yr suffer a stroke-5 mill die & 5 mill permanently disabled
a stroke occurs every 5 s
Stroke related disability: 6th most common cause of reduced DALYs
Accounts for 10% and 2nd cause of all deaths
TIA:
- Temporary focal loss of neurologic function caused by ischemia
- Most resolve within 3 hrs (thrombotic: u lasts for 10 min, embolic: u >1hr)
- u thrombotic, u in SLEEP
- May be due to micro-emboli that temporarily block blood flow
- A warning sign of progressive cerebrovascular disease (risk of stroke high in next few days)
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Treatment:
- BP: DON'T decr it (in first 24hrs) unless
- ischemic: SBP > 210,220 or accompanied by acute MI, aortic aneurysm, renal impairments,..
- hemorrhagic: SBP > 170,180
- recombinant tissue plasminogen activator: decr disabilities