ischemia stroke / TIA Flashcards
What percentage of all strokes are ischemic strokes?
80-85%
Ischemic strokes are the most common type of stroke.
What is the primary mechanism leading to ischemic stroke?
Blood vessel obstruction
This leads to an ischemic core surrounded by an ischemic penumbra.
What is the ischemic penumbra?
Area of potentially salvageable tissue with reduced blood flow
Can be recovered if reperfusion occurs rapidly (3-4 hours).
What are the main causes of ischemic stroke?
Thromboembolism, hypercoagulable state, hypoperfusion, unusual causes
Includes thrombosis at atheromatous plaque, cardiac sources, and conditions like aortic dissection.
What is thromboembolism?
Thrombosis and embolism
Thrombosis occurs at atheromatous plaque, while embolism can arise from distant plaques or cardiac sources.
What are common cardiac sources of embolism?
Mural thrombus after MI, A. Fib, MS, dilated cardiomyopathy, patent foramen ovale, endocarditis, prosthetic valve
These conditions increase the risk of embolic strokes.
What is the most important modifiable risk factor for ischemic stroke?
Hypertension
It is considered the #1 risk factor.
List non-modifiable risk factors for ischemic stroke.
- Age
- Family history
- Race (African American)
- Gender (estrogen protective in premenopausal females)
These factors cannot be changed.
What are some modifiable risk factors for ischemic stroke?
- Previous stroke/Transient Ischemic Attack
- Heart disease (A. fib → embolism)
- Hyperlipidemia
- Smoking
- Alcohol
- Cocaine & amphetamine abuse
- Hypercoagulability
- Polycythemia
- Sickle cell disease
Lifestyle changes can impact these factors.
What are the common symptoms of ischemic stroke?
Negative symptoms (loss of function)
Symptoms depend on the territory affected.
What area is the commonest site for embolism in ischemic stroke?
Middle cerebral artery
Symptoms include face & arm weakness greater than leg weakness.
What symptoms are associated with middle cerebral artery strokes?
- Contralateral homonymous hemianopia with ipsilateral gaze deviation
- Aphasia (if dominant hemisphere affected)
- Apraxia, agraphia, neglect, agraphesthesia, astereognosia (if non-dominant)
These symptoms vary with the hemisphere affected.
What symptoms are associated with anterior cerebral artery strokes?
- Leg weakness > arm weakness
- Cognitive or personality changes
- Abulia if bilateral
- Apraxia
This territory is less commonly affected than the middle cerebral artery.
What symptoms are associated with posterior cerebral artery strokes?
- Contralateral homonymous hemianopia with macular sparing
- Visual agnosia
Affects the visual processing areas of the brain.
What are the symptoms of posterior circulation strokes?
- Diplopia
- Vertigo
- Dizziness
- Ataxia
- Dysarthria
- Dysphagia
These symptoms indicate involvement of the brainstem and cerebellum.
give examples for the causes of ischemic stroke
hypercoagulable state: antiphospholipid syndrome
hypoperfusion: watershed infarction
others: aortic dissection, vasculitis, drug abuse
What is an ischemic stroke?
A type of stroke caused by a blockage of blood flow to the brain.
What are the complications of ischemic stroke?
Cerebral edema, hemorrhage into the infarction, seizures.
What are lacunar infarcts?
Small, deep infarcts caused by occlusion of penetrating brain arteries in deeper brain structures.
Which brain structures are affected by lacunar infarcts?
Basal ganglia, internal capsule, thalamus, pons.
What characterizes pure motor lacunar infarcts? And where’s the lesion located?
Weakness on one side without sensory or cortical involvement.
Posterior limb of internal capsule
What characterizes pure sensory lacunar infarcts? And where’s the lesion located?
Numbness without weakness or cortical involvement.
VPL nucleus of thalamus.
What is ataxic hemiparesis?
Ipsilateral weakness and limb ataxia out of proportion to motor deficit.
What additional symptoms may accompany ataxic hemiparesis?
Dysarthria, nystagmus, gait deviation towards.
What characterizes sensorimotor lacunar infarcts? And where are the lesions located?
Weakness and numbness on one side without cortical involvement.
Posterolateral thalamus and posterior limb of internal capsule.
What is dysarthria - clumsy hand syndrome? Where the lesion located?
Facial weakness, dysarthria, dysphagia, slight weakness, clumsiness of one hand.
Lesion in the pons
What is the modality of choice for diagnosis of cerebrovascular accidents? Why?
Brain CT
It is done first to exclude hemorrhage.
How does ischemic stroke appear on a CT scan compared to hemorrhagic stroke?
Ischemic = hypodense
Hemorrhagic = hyperdense
This distinction is crucial for diagnosis.
List the blood tests required for diagnosing ischemic stroke.
- CBC
- Blood sugar
- Lipid profile
- Coagulation profile
These tests help evaluate overall health and risk factors.
What ECG findings may indicate ischemic stroke?
Acute MI or AF
These conditions can contribute to stroke risk.
What is the primary management goal for a patient with ischemic stroke?
Protect the airway
Maintaining airway protection is crucial for patient safety.
What should be monitored in a patient with ischemic stroke?
- Blood glucose
- Temperature
- Blood pressure
These parameters are vital for managing stroke patients.
What is the recommended blood pressure goal for a stroke patient not receiving tPA?
< 220/110
Controlling blood pressure is crucial to prevent ischemic core expansion.
What is the recommended blood pressure goal for a stroke patient receiving tPA?
< 185/110
This is to ensure safety during thrombolytic therapy.
What serum glucose level should be maintained in stroke patients?
< 140 mg/dL
Avoiding hyperglycemia is important for recovery.
What should be done if hemorrhage is excluded with CT and the patient is within the 3 to 4.5 hours window?
Start thrombolytics (tPA)
Thrombolytics can significantly improve outcomes if administered in time.
What should be given after thrombolytics if within the window period?
Wait for 24 hours, then start aspirin
This protocol helps prevent further clotting.
What should be administered if a patient is already on aspirin?
- Add dipyridamole
- Switch to clopidogrel
Adjusting antiplatelet therapy is critical for management.
What are the inclusion criteria for thrombolytics (tPA) within the window?
- NIHSS ≥ 4
- Baseline CT shows no ICH or early hypodensity affecting > 1/3 of MCA territory
These criteria help determine eligibility for treatment.
What are some exclusion criteria for thrombolytics (tPA)?
- Anything increasing the chance of bleeding
- Blood on CT
- Recent surgery or bleeding (2 weeks)
- Severe head trauma (past 3 months)
- Previous ICH
- Coagulation problems
- BP > 185 or > 110
- Glucose < 2.8 or > 22
These criteria help prevent complications during treatment.
What should be done if tPA is complicated by intracerebral hemorrhage?
- D/C tPA
- Take blood for coagulation profile, type & cross match, and fibrinogen
- Immediate CT & contrast neurosurgery
Rapid response is essential to manage complications.
What should be administered in case of tPA-related hemorrhage?
- 6-8 units IV cryoprecipitate
- Platelets
- +_ Recombinant activated factor 7
These treatments help manage bleeding complications.
What is the role of high dose statins in managing ischemic stroke?
Anti-inflammatory effect regardless of LDL level
Statins can provide benefits beyond cholesterol reduction.
What type of IV fluids should be avoided in stroke management?
Dextrose containing fluids
Avoiding these fluids helps prevent increased edema.
What treatments can be used for increased ICP?
- Hyperventilation
- Mannitol
These treatments help reduce intracranial pressure.
What is endovascular thrombectomy useful for?
Catheter removal of the clot up to 8-12 hours in proximal anterior circulation occlusion
This procedure can restore blood flow in certain cases.
What is a Transient Ischemic Attack (TIA)?
Focal brain or spinal disturbances that usually last less than 24 hours and resolve completely with normal imaging.
What are some common presentations of TIA?
- Visual field cuts
- Dysarthria
- Double vision
- Vertigo
- Numbness
- Weakness
- Focal sensory/motor disturbances
What is the ABCD2 score used for?
To assess the risk of stroke after a TIA.
What factors contribute to the ABCD2 score?
- Age ≥ 60 (1 point)
- BP ≥ 140 systolic or 90 diastolic (1 point)
- Clinical features (silent disturbance without weakness) (1 point)
- Duration of symptoms (10-59 min = 2 points; < 10 min = 0 points)
- Diabetes mellitus (1 point)
When should an MRI be done after a TIA?
Within 24 hours if the ABCD2 score ≥ 4 or if there are crescendo TIAs (≥ 2/week).
What imaging studies can be used to assess TIA?
- ECG + Holter
- Echocardiogram (to check for thrombus or vegetations)
- Carotid ultrasound (may show carotid dissection or stenosis)
What is the chronic treatment for TIA?
- Aspirin
- Statin
- Risk factor control
What characterizes Broca’s Aphasia?
Slow, laborious, non-fluent, poorly articulated speech with preserved word comprehension.
Where is the ischemic area typically located in Broca’s Aphasia?
Left posterior inferior frontal cortex, in the distribution of the superior division of the left middle cerebral artery (MCA).
What characterizes Wernicke’s Aphasia?
Fluent but meaningless speech output and repetition, with poor word and sentence comprehension.
Where is the ischemic area typically located in Wernicke’s Aphasia?
Posterior superior temporal cortex, in the distribution of the inferior division of the left MCA.
What is Global Aphasia?
Severe impairment in all aspects of language, often involving both anterior and posterior language areas (Broca and Wernicke areas).
True or False: In Broca’s Aphasia, patients can understand spoken language.
True
Fill in the blank: Broca’s Aphasia is characterized by _______ speech.
non-fluent
Fill in the blank: Wernicke’s Aphasia results in _______ comprehension of language.
poor
