Strokes! Flashcards
2 major types of strokes?
- hemorrhagic = 15%
- ischemic = 85%
- large artery thrombosis: d/t atherosclerosis and ischemia of the vessel- often internal carotid
- embolic stroke
embolic stroke
types:
- from atherosclerotic plaque
- from thrombus
source:
1. heart: (often blood stasis –> thrombus formation)
- atrial fib, atrial septal aneurism, atrial myxoma,
- ventricular source: cardiomyopathy, MI, ventricular aneurism
- rheumatic mitral stenosis
- prosthetic valves
- endocarditis
- bicuspid aortic valves
- artery
- carotid artery atherosclerosis/stenosis causes 5% of strokes - lower extremity DVT w/ paradoxical emboli
- d/t atrial septal defect
lacunar infarct
d/t HYPERTENSION!
- may be b/c of atheroemboli or lipohyalinosis
- affects SUBCORTICAL areas of brain that are supplied by small deep penetrating arteries that arising from the big arteries:
- 15-25% of ischemic strokes
- often asymptomatic
- lipohyalinosis:
High pressure of large arteries transmitted to small arteries
Hyperplasia of small vessel walls
Hyalinization of the vessel walls
Narrowing and then occlusion of the lumen
watershed infarcts
occur at area b/w MCA-ACA when BP drops: i.e. sepsis, bloodloss, dehydration
hypercoagulable disorders
Most of them cause venous clotting more than arterial clotting due to slower venous flow
Factor V Leiden mutation (most common) - the Leiden variant of factor V cannot be inactivated by the anticoagulant protein activated protein C, so clotting is encouraged
Protein C deficiency Protein S deficiency Antithrombin deficiency Plasminogen deficiency Prothrombin gene mutation
disorders more likely to cause arterial clotting?
Antiphospholipid antibody syndrome:
- Anticardiolipin antibodies (ACA)
- Lupus anticoagulants (LA)
Hyperhomocysteinemia
cocaine use?
causes SA bleeding and vasospasm stroke
hemiparesis
weakness of one side of the body
hemiplegia
– complete paralysis of one side of the body
Acalculia
difficulty to perform simple math tasks
Agnosia
inability to recognize objects, persons, sounds, shapes, or smells
Aphasia
inability to speak (motor or sensory)
Alexia
inability to read
agraphia
inability to write
dysphagia
inability to swallow
dysarthria
slurred speech
Hemispatial Neglect
inability to attend to one side of the body or visual field
Apraxia
– inability to perform a specific task
Anosognosia
unawareness of or denial of the existence of disability
Anomia
difficulty with recalling words or names
ataxia
unsteady gait
MCA syndrome
MCA supplies face portion of homunculus ** most common type **
- Motor Cortex + Sensory Cortex: upper limb and face
- Contralateral hemiplegia/sensation loss (sometimes in face and upper extremity only)
- Contralateral Homonymous Hemianopsia - Temporal Lobe (Wernicke’s)
and frontal lobe (Broca’s)
- Dominant hemisphere: (usually left)
Aphasia, alexia, agraphia, acalculia, finger agnosia, and right-left confusion.
- Non-dominant side (usually right):
hemineglect, dressing apraxia, anosognosia, and constructional apraxia
ACA syndrome
anterior cerebral artery supplies the exremities portion of homunculus
motor cortex and sensory cortex: results in contralateral paralysis and loss of sensation of lower extremity
PCA syndrome
posterior cerebral artery supplies the occipital and visual cortex
- Contralateral Homonymous hemianopsia
- Alexia without agraphia**
- Visual or color anomia
lenticulostriate artery stroke
supplies striatum and IC — common location of lacunar infarcts secondary to unmanaged HTN
** contralateral hemiparesis/hemiplegia **
AICA syndrome
“lateral pontine syndrome”
** facial nucleus most affected**
Lateral pons - CN nuclei VIII, VII, V:
- ** paralysis of face** = “facial droop”
- ** loss of ipsilateral pain/temp on face and contralateral pain and temp of body **
Middle and inferior cerebellar peduncles: ataxia and dysmetria of arm and leg
PICA syndrome
= “lateral medullary syndrome” = “wallenburg syndrome”
Lateral medulla: vestibular nuclei, lateral spinothalamic tract, spinal trigeminal nucleus, nucleus ambiguous, sympathetic fibers
- decreased pain and temp from ipsilateral face and contralteral body
- dysphagia, hoarseness, decreased gag reflex**
- Horner’s syndrome **
- ataxia, dysmetria
- nystagmus, vertigo, hiccups
basilar artery strokes
pons, medulla, lower midbrain, corticospinal and corticobulbar tacats, ocular CN nuclei
** results in locked in syndrome ** - have preserved consciousness, blinding, quadriplegia, loss of voluntary facial, mouth and tongue mvmts
ASA
“medial medullary syndrome” - though its often b/l
- provides lateral corticospinal tract:
- results in c/l hemiparesis of upper and lower limbs - provides medial lemniscus:
- decreased contralateral proprio - caudal medulla - hypoglassal nerve
- ipsilateral hypoglossal dysfunction, tongue deviates ipsilaterally (points to bad side! d/t collapse on other side of mm.)
ventral pontine syndromes:
= basilar artery strokes
Ventral pontine syndrome (Raymond Syndrome)
Lateral gaze weakness
Contraletaral hemiplegia
Ventral pontine syndrome (Millard-Gubler Syndrome)
contralateral - upper and lower extremity weakness
Ipsilateral facial weakness
amaurosis fugax
Transient mono-ocular blindness (in one eye)
Often warning sign of an impending stroke !!
Several causes:
- Embolic (most often from carotid artery of the same side)
- Hemodynamic
- Ocular
- Neurologic
- Idiopathic
TIA
“ministroke”
- sx are same as the stroke but they only last 24 hours or less!
- 15-40% result in infarcts and 10% of patients have the risk of CVA w/in 3 months!
ddx and tx of stroke?
Always first do CT: rules out hemorrhage
Acute tx of stroke:
- rtPA clot buster (only after CT)
- aspiring
- IV fluids
- keep BP maintained
Stroke vs Bell’s palsy
Stroke= ischemia of cortex = often only results in lower portion of face losing motor control (d/t c/l unilateral innervation), but can wrinkle upper forehead (b/c its innervated bilaterally)
Bell’s Palsy = loss of CN VII = ipsilateral facial weakness= “one sided facial droop” affects both upper and lower portion of face
stroke risk factors? stroke prevention meds?
Age. Risk doubles with each decade after 55
Heredity (Family history)
Race
African Americans and Hispanics higher than Caucasians
Gender
More men has strokes in a given year in each age group
More than half of total stroke deaths occur in women
Personal h/o TIA, CVA, MI, any atherosclerosis
modifiable risks:
- HTN, A fib, smoking, DM, carotid stenosis, hyperlipidemia
- obesity, alcohol
stroke prevention meds? Antiplatelets agents - Aspirin - Clopidogril (Plavix) - Aspirin/dipyridamole (Aggrenox)
Anticoagulation agents
- Warfarin (Coumadin)
- Heparin and LMWH
main cause of lacunar strokes?
HTN!!!
