Cerebrovascular Disease Flashcards
Risk factors for stroke
Similar to those for CAD (HTN, DM, smoking, dyslipidemia)
Men higher incidence at younger ages and higher for women by age 75
What causes a CVA?
Acute neurologic injury occurring due to hemorrhage or ischemia
Causes of ischemic stroke
Thrombosis (in situ obstruction of artery)
Embolism (a fib sends from somewhere else in body)
Hypoperfusion (circulatory problem)
Presentation of ischemic stroke due to hypoperfusion
Pts have evidence of circulatory compromise with hypotension and may have pallor, sweating, tachycardia/bradycardia, kidney dysfunction
Neuro signs are usually more bilateral (more uniform sxs)–sxs of brain dysfunction more diffuse and nonfocal
What are watershed infarcts?
Susceptible to strokes and ischemia secondary to low flow states from vessel overlap or systemic hypotension (some arteries will do a little perfusion into an area that another artery usually does)
What can cause a hemorrhagic stroke?
Intracerebral hemorrhage (parenchymal)- bleeding directly into tissue (more common type here) Subarachnoid hemorrhage-bleeding into CSF
Most common type of CVA
Ischemic!!
Why do you need to differentiate ischemic and hemorrhagic stroke?
For tx!! (do by a CT)
How is ischemia shown on CT?
Hypodense (darker) area of brain tissue
How to divide stroke syndromes
Large vessel: within anterior or posterior circulation
Small vessel: disease of either vascular bed (lacunar stroke)
Stroke syndrome due to large vessel in anterior circulation
(carotid artery supply)
Extracranial and intracranial carotid arteries, middle and anterior cerebral artery branches (middle/anterior cerebral artery, anterior communicating)
Stroke syndrome due to large vessel in posterior circulation
(vertebrobasilar system)
Extracranial and intracranial vertebral arteries, basilar artery and posterior cerebral arteries
CVA most commonly due to which artery
Middle cerebral artery
What does a stroke in middle cerebral artery affect?
Frontal, temporal and parietal lobes
Presentation of stroke syndrome due to middle cerebral artery (anterior)
Contralateral hemiplegia/hemianesthesia (weakness/numbess) variably affecting FACE and ARM greater than leg
Can see contralateral homonymous hemianopia and a day or two of gaze preference to ipsilateral side can be seen
Different presentations of stroke due to middle cerebral artery for dominant or nondominant hemisphere
Dominant: global aphasia (trouble talking)
Non dominant: hemineglect (half of world means nothing)
Presentation of stroke due to anterior cerebral artery
(frontal pole/lobe)
Contralateral hemiplegia/hemianesthesia (weakness/numbess) in the LEG greater than the arm
May have profound abulia (delay in verbal and motor response) or perseverating speech
Presentation of stroke due to anterior communicating artery
Impingement of cranial nerves so visual field deficits
Presentation of stroke due to posterior cerebral artery
(occipital cortex)
Contralateral homonymous hemianopia
Light touch and pinprick sensation may be reduced
-stroke may go unnoticed by pt b/c motor involvement is usually minimal unless large infarct
What presentation is seen with stroke due to posterior inferior cerebellar artery (PICA)?
Wallenbergs syndrome (lateral medullary syndrome)
What is Wallenbergs syndrome?
Ipsilateral loss of facial pain and temp sensation with contralateral loss of these senses over body
VERTIGO, VOMITING, nystagmus, ipsilateral ataxia, hoarseness, dysarthria, dysphasia, hiccups, ipsilateral Horners syndrome
(PICA)
What is Horners syndrome?
Typically incomplete ptosis and miosis without anhidrosis
Presentation of stroke due to basilar artery
Complete occlusion affects pons and produces LOCKED IN SYNDROME
What is the locked in syndrome?
Quadriplegia and facial/mouth/tongue weakness
Preserved consciousness (reticular formation spared)
Preservation of vertical eye movements and blinking
(basilar)
What is a lacunar stroke?
Occlusion of one of small, penetrating branches of circle of willis, middle cerebral artery stem or vertebral and basilar arteries
Thrombosis causes small infarcts called lacunes
What is a lacunar stroke associated with?
Chronic untreated HTN
Initial assessment for all kinds of strokes
Airway
Breathing
Circulation
What to remember with stroke pts and airway
They can have increased ICP which can lead to a decreased respiratory drive (may need to intubate, also if don’t have good level of consciousness)
What tends to be elevated in pt with acute stroke?
Mean arterial pressure (maybe due to HTN which is risk factor for stroke)
*appropriate response to maintain brain perfusion
BP control for ischemic stroke
DO NOT START treating BP unless greater than 220/120 (b/c risk of further ischemia)
BP for hemorrhagic stroke
Keep the BP <160/90 to prevent increases in bleeding (but don’t want it below 140 to prevent ischemia in other places)
Most important history question for stroke
When did the sxs start??
First diagnostic test to assess for stroke
Noncontrast CT of brain
What test is more sensitive for ischemia earlier on in CVA but not widely available?
Stat diffusion weighted MRI
Other diagnostics done for CVA
Electrocardiogram CBC with platelets Serum glucose PT and INR PTT Cardiac enzymes (troponin) Lytes, BUN, Cr
CT scan and hemorrhagic stroke
Diagnose of this is largely based on results of CT (shows blood in area suffering stroke)
CT scan and ischemic stroke
May be normal (b/c take a certain length of time to be evident on CT)
When might the diagnosis of stroke have to be clinical b/c CT results come up normal?
Sxs present <6 hrs
Affected area is small
Located in area of brain not well seen on CT (posterior fossa)
AND CVA secondary to ischemia (then normal)
General rule for management of all pts with acute CVA
They are critical so need ABCs and admit to ICU
Early tx for acute ischemic stroke
Initiate ASA within 48 hrs (maybe dual antiplatelet therapy with clopidogrel and ASA for pt with high risk TIA or minor stroke)
What to do if brain CT shows no bleed!!!
Full dose aspirin within 48 hrs (rectally if pt has dysphasia)
-ASA reduces risk of early recurrent ischemic stroke
Choices for secondary stroke prevention
ASA, clopidogrel (Plavix) and combo of ASA extended release dipyridamole
Best way to save ischemic brain tissue not already infarcted
Timely restoration of blood flow with thrombolytics (but don’t want to create a hemorrhagic stroke!!!)
When can you not do tPA (thrombolytic)?
Not recommended beyond 4.5 hrs of sxs
BP therapy if giving thrombolytics
Systolic <185 and diastolic <110
Timeline for initiating thrombolytic therapy
Eval- 10 min Stroke or neuro expertise contacted-15 min CT/MRI- 25 min Interpret scan- 45 min Start IV tPA-60 min
General rule to consider tPA
CT scan must be normal (if shows ischemia then it has been going on too long to consider tPA safe)
Intra arterial thrombolysis for CVA
Catheter directed tPA (smaller dose than peripheral IV but not proven beneficial)
Mechanical thrombectomy for CVA
Endovascular tx with stent retriever for pts with intracranial large artery occlusion in proximal anterior circulation (if can be treated within 6 hrs of sx onset)
Therapy for hemorrhagic stroke
D/c all anticoagulants and antiplatelet drugs (reverse effects immediately)
How to lower ICP that is seen with hemorrhagic stroke
Elevate heard of bed to 30 degrees and use analgesia and sedation
Osmotic diuretics, drainage of CSF (bolt), neuromuscular blockade and hyper ventilation (short term)
When is it needed to do surgical consult to immediately remove the hemorrhage
Cerebellar hemorrhage >3 cm
Pts deteriorating or have brainstem compression and/or hydrocephalus due to ventricular obstruction
Secondary prevention of ischemic stroke
Antiplatelet meds, warfarin (afib or prosthetic heart valve)
Secondary prevention for either type of CVA
Tx of underlying conditions (DM, HTN, HLD)
Stop smoking, alcohol, drugs
What is a TIA?
Transient episode of neuro dysfunction caused by focal, brain, spinal cord or retinal ischemia
WITHOUT ACUTE INFARCTION (but even short periods of time can cause permanent brain injury)
(used to be <24 hrs but they are mostly <60 min)
Why is a TIA important?
Stroke risk within first 2 days in higher and even higher in next 5 yrs
Stroke prevention after TIA
EKG (tx of afib) Carotid u/s (maybe carotid endarterectomy) Lipid lowering med AntiHTN med Diet/lifestyle Start daily ASA therapy
What to do if pt is on ASA and has meds for risk factors but still has a TIA?
Maybe add clopidogrel or aspirin extended release dipyrimadole
High risk factors with presentation of HA
New HA
Severe
Sudden
AMS
What is needed with pt with HA and high risk features
Noncontrast brain CT
What to do if CT is normal but pt has severe HA
LP
HA with SAH
Sudden and thunderclap (worst headache of life)
Most common cause of SAH
Ruptured saccular aneurysm or trauma (many ppl have them and they don’t rupture)
Who do you see SAH in?
40-60 YO
Slightly higher risk of aneurysmal SAH in women
Risk factors of SAH
Aneurysms in other vessels, connective tissue disorder, HTN/HLD, DM, CVD, obese, polycystic kidney disease, smoking/alcohol, family hx
Common complications of SAH
Vasospasm (b/c of spasmogenic substances during lysis of subarachnoid blood clots)
Rebleeding (within first day usually)
When do you see vasospasm vs rebleeding?
Rebleeding is early
Vasospasm is no earlier than day 3 and peaks at day 7
What will show blood in subarachnoid space in performed within 24 hrs of bleed?
Noncontrast CT scan of brain
How to diagnose SAH in pt with suspected one but negative CT
LP! (look for bleeding b/c normal CSF has no RBCs or WBCs)
How to tell difference between traumatic tap and SAH?
Traumatic-RBC numbers tend to decrease from 1st to 4th tube (stay same if SAH)
Most sensitive indicator of SAH on LP
Xanthochromia (pink or yellow tint to CSF due to hemoglobin degradation products)
Management of SAH
Admit to ICU
Analgesia to diminish hemodynamic fluctuations and help prevent re bleeding
Control ICP
Serial transcranial doppler u/s to monitor for vasospasm
Stop blood thinners, seizure prophylaxis
How to prevent vasospasm
IV fluids and nimodipine (oral or NG tube within 4 days) (for about 2 wks-21 days)
Mainstay of therapy for SAH
Surgery of aneurysms (clipping)
Endovascular (coiling) becoming more widely used
Prevent re bleeding and stop another aneurysm from rupturing later
Traumatic SAH?
Consequences generally not as bad as with spontaneous
