Neurology
Vascular Emergencies
- Stroke
- Definition
- Stroke is defined as an acute focal neurological deficit due to interruption of blood flow through a cerebral vessel
- Brain attack
- Most disabling neurologic disorder
- Important Stroke Facts
- A stroke occurs every minute in the US
- Long hospital stay
- Leading casue of transfer to long term facility
- Cerebral vascular accident: 2 types
- Ischemic- Brain cell nutrients are blocked leading to cell deaths
- Embolic
- Thrombotic
- Hemorrhagic- blood is neurotoxic to surrounding cells leading to cell death
- Risk factors
- Cardiac disease/Hypertension
- Smoking
- Diabetes
- Obesity
- Oral contraceptives
- Sickle Cell Anemia
- Migraine
- Types of Ischemic Stroke:
- Ischemic penumbra in evolving stroke
- Transient Ischemic Attacks- Brain angina
- Large Vessel Thrombotic Stroke
- Small Vessel Lacunar Stroke
- Cardiogenic Embolic Stroke
- Penumbra
- Band of minimally perfused cells
- Blood flow to this “halo” is decreased
- Survival depends on timely return of circulation, toxic products released by the dying cells, the degree of cerebral edema, blood flow
- Transient Ischemic Accident
- Temporary disturbance in cerebral blood flow. Reverses prior to injury. Focal ischemic neurological deficit that lasts < 24 hours
- Etiology is atherosclerotic disease of cerebral vessels and emboli
- Often present with amaurosis fugax- clot from carotid to the retinal artery and temporary loss of vision
- Differential diagnosis to include: seizure, migraine, syncope
- Diagnostic studies
- Arteriogram
- Magnetic resonance angiography
- Cardiac workup/carotid Doppler
- Hematologic workup for coagulopathies, syphilis serology, CBC
- Echocardiogram
- Large Vessel Thrombotic Stroke
- Etiology is atherosclerotic plaques found at bifurcation of carotid artery or medium sized arteries
- Most commonly the middle cerebral artery
- Defects to the cortex
- Rapid onset- awake from sleep with symptoms
- Apraxia- can’t perform purposeful movements
- Small Vessel Lacunar Infarct
- Affects subcortical structures such as basal ganglia, thalamus, internal capsule, brain stem
- Stenosis of vessel lumen due to thickening of vessel wall
- Lacunes- infarct that has healed
- Does not affect cortex, affects brainstem- nausea and dizziness
- Risk factors: Include hypertension and diabetes
- Clinical manifestations include contralateral pure motor or pure sensory
- Diagnosis
- Clinical
- MRI
- Cardiogenic Embolic Stroke
- Etiology is thrombus from heart (rheumatic heart disease, atrial fibrillation, bacterial endocarditis)
- Most likely affecting the middle cerebral artery
- Can be caused by plaque in carotid arteries
- Clinical presentation
- Prevention includes treating heart disease including anticoagulation therapy
- Clinical presentation
- Thrombotic strokes- wake up during sleep
- Embolic strokes- suddenly during waking hours
- Hemorrhagic strokes- evolve over minutes
- History of TIA
- Involve weakness/numbness, dysarthria, gait disturbance
- Vision loss in one eye is a sign of TIA or impending stroke- amaurosis fugax
- Abrupt onset of neurologic problems and can have cardiac problems
- Cerebral Circulation
- Two internal carotids and two vertebral arteries
- Major branches of the Internal Carotid Artery
- Middle Cerebral Artery
- Anterior Cerebral Artery
- Homunculus
- MCA
- Contralateral hemiparesis, hemisensory deficit
- Homonymous hemianopsia opposite occluded artery
- Aphasia possible
- Confusion, apraxia, contralateral body neglect
- ACA
- Contralateral weakness
- Broca’s aphasia
- Incontinence
- Vertebral Arteries
- Merge at pons to form single basilar artery
- Posterior cerebral arteries (2)- supply occipital lobes and thalamus and upper midbrain
- Branches of the basilar and vertebral arteries arteries supply the medulla, pons, cerebellum, midbrain, and part of the diencephalons
- Respiratory problems, nausea, vomiting
- Posterior cerebral arteries supply remaining occipital and inferior regions of the temporal lobes and thalamus
- Vertebrobasilar Artery
- Involves cerebellum and brain stem- diplopia, vertigo, nausea, vomiting, dizziness
- Posterior cerebral artery
- Involves occipital lobe, portions of temporal lobe, thalamus
- Homonymous hemianopsia of contralateral visual field
- Vertical gaze, occulomotor nerve palsy
- Aphasia or alexia- can’t read
- Pupillary response intact
- Diagnosis
- CT scan
- Carotid Doppler and ultrasound
- Complete cardiological work-up including echocardiogram
- Labs to rule out other origins
- MRI for ischemic lesions and for follow-up
- Perfusion scans
- Arteriography
- Magnetic resonance angiography
- TIA
- Management
- Antiplatelet therapy
- Anticoagulant- for ischemic stroke due to cardiac embolus
- Endarterectomy
- Cerebrovascular accident
- Ischemic type management
- Anticoagulation with heparin
- Antiplatelet therapy
- Anticoagulation
- Window of opportunity with thrombolytics (tpa, tissue plasminogen activator)
- Lyses fibrin containing clots
- Who are the candidates for thrombolytics therapy?
- CT
- Three hour window for administration
- B/P <185/110
- No anticoagulants within 48 hours
- Platelet count >100,000
- No previous CVA or head trauma in preceding 3 months
- No major surgery in past 14 days
- No history of intracranial bleeds
- No rapid improvement
- No GI or GU hemorrhage within 21 days
- No seizure with onset of stroke
- Glucose >50, <200
- Complications
- Motor/Sensory deficits
- Language/speech deficits
- Speech
- Language
- Dysarthria- slurred speech
- Cognitive deficits
- Risk of contractures, need patient
- Dehabilitating
- Cerebral Aneurysm- hemorrhagic stroke
- Bulge in the muscular wall of an arterial vessel
- Causes bleeding into the subarachnoid space
- Risk factors include polycystic kidney disease, coarctation of aorta, arteriovenous malformations of the brain, hypertension, atherosclerosis
- Rupture leads to subarachnoid hemorrhage
- Non-ruptures
- Asymptomatic
- Large aneurysm
- Chronic headache
- Neurologic deficits
- Cerebral aneurysm ruptures
- Ruptured berry aneurysm account for 75% of non-traumatic subarachnoid hemorrhage
- Etiology includes aneurysm, trauma, erosion of the vessels by tumors, blood coagulation disorders
- Spontaneous hemorrhage of blood into brain tissue
- Risk groups age 50-60, hypertension
- Clinical presentation
- Sudden and severe generalized headache
- Collapse and loss of consciousness
- Vomiting
- Nuchal rigidity, photophobia
- Cranial nerve deficits
- Focal motor and sensory deficits
- Cerebral edema, increased ICP
- Hypertension
- Pituitary dysfunction
- Fever up to 102 F with confusion, stupor, and coma
- Diagnosis
- CT to identify aneurismal rupture
- CSF- elevated opening pressure containing bloody fluid
- Cerebral angiography- look for berry aneurysms
- Complications
- Vasospasm with cerebral ischemia
- Hydrocephalus
- Hypothalamic dysfunction
- Seizures
- Management
- Cerebral arteriography- within 24-72 hours
- Surgery
- Supportive treatment to prevent elevated arterial or intracranial pressures- if bursted
- Decrease or maintain cranial pressure
- Hypertension management
- Arteriovenous Malformation- no capillary bed
- 10% of subarachnoid hemorrhage
- Risk groups 20-40 years
- Congenitally abnormal arteries and veins
- Present with hemorrhagic stroke
- Veins exposed to high pressure of arteries
- Clinical presentation
- Subarachnoid hemorrhage
- Seizures
- Headache-throbbing
- Hemiparesis
- Speech deficits
- Learning disorders
- Diagnosis
- Cerebral angiography
- Management
- Surgical, endovascular occlusion