Everything a person can see when the eyes are fixed. AKA Field of Vision
Episode
Noteworthy event or series of events
Amaurosis Fugax
Sudden temporary blindness
Episodic Monocular Blindness: A shade being pulled down over one eye or FOV
What is the most common cause of Amaurosis Fugax?
Plaque embolus or thromboembolus from the ipsilateral ICA
What is Hollenhorst Plaque?
Bright plaque within the vessels of the retina
Cholesterol crystals are contained within the atheromatous
Diplopia
Double vision
Homonymous Hemianopsia
bilateral blindness in half of each eye
Monocular Blindness
Temporary blindess in one eye; Amaurosis Fugax
If there is damage to the left side of the brain, where will vision be affected?
Right side of each eye
Dysarthria
Poor articulation, slurred speech
Dysphasia
Impairment of speech. The patient knows what he/she wants to say, but can't speak easily
Aphasia
Loss of expression of speech and comprehension of language
Dysphagia
Difficulty swallowing
Paresis
Partial or incomplete paralysis (weakness)
Hemiparesis
Partial or incomplete paralysis affecting only one side of the body
Plegia
Complete paralysis or stroke
Hemiplegia
Paralysis of one half of the body
Paresthesia
Numbness, tingling or lack of feeling
Monoparesis
Partial paralysis in one limb
Ataxia
Failure of muscular coordination
What are two other stroke symptoms?
Confusion and headaches
Dizziness
Feeling a tendency to fall
Vertigo
Sensation of moving around in space
Nausea
An unpleasant sensation usually preceding vomiting
Syncope
Pass out
Drop attacks
Failure of a part to maintain its normal position
What are the two types of stroke?
Hemorrhagic and Ischemic
Brain Hemorrhage
The rupture of an aneurysmal artery
What are the causes of brain hemorrhage?
AV Malformation
Trauma
Atherosclerosis
Inflammation
What happens to a patient with a hemorrhagic stroke?
Blood flows into or out of the brain
30-50% of patients die
Types/Locations of Intracranial Hemorrhage (ICH)
Epidural: between dura mater and skull
Subdural: between dura and arachnoid mater
Subarachnoid (SAH): between arachnoid and pia mater
Intraparenchymal: Within the brain
Approximately how many strokes occur as a result of subarachnoid bleeds?
10%
Epidural, Subdural, and Intraparenchymal Hemorrhage account for ___% of stroke?
10%
Ischemic stroke is responsible for ___% of stroke
80%
How are ICHs treated?
To prevent further bleeding, the ruptured vessel needs to be occluded by surgical clip/repair, embolic therapy, or thrombus formation
What are three other ICH concerns?
Pressure from bleed and resultant hematoma
Vasospasm
Hydrocephalus
Pressure from bleed and resultant hematoma
When an aneurysm ruptures, blood extravasates under arterial pressure into the subarachnoid space and quickly spreads through the cerebrospinal fluid around the brain and spinal cord. Blood released under high pressure may directly cause damage to local tissue.
True/False: The damage caused by ICH is proportional to the volume of blood that extravasates from the ruptured vessel
True
Vasospasm
The pathophysiology of vasospasm is unclear
Spasm rarely occurs before the ___ day after the hemorrhage
3rd day
Vasospasm induced by SAH
Depends on amount of blood around the brain and resultant hematoma
Usually very ill patients already in the hospital
Many times the patients have involuntary movements
Neurologic deficit evidenced by cranial nerve involvement
moderate to severe headache with pronounce meningeal signs
(Photophobia, nuchal rigidity)
SAH Grade 3
Drowsiness and confusion with or without focal neurologic deficits
Pronounced meningeal signs
SAH Grade 4
Stuporous with pronounced neurologic deficits
(Hemiparesis, dysphagia)
Nuchal rigidity
SAH Grade 5
Deep coma state with decerebrate posturing and other brain stem dysfunction
ICH clinical manifestations
Sudden throbbing, or explosive headache
Nausea or vomiting
Visual disturbances
Motor deficits
Loss of consciousness
Ischemic stroke: lack of oxygen to the brain cells due to...
Atheroembolus: A fragment of plaque travels to the brain and occludes a small artery that feeds brain cells
Thromboembolus: A fragment of thrombus travels to the brain and occludes a small artery that feeds brain cells
Stroke facts
Cerebrovascular disease is the 3rd leading cause of death in the US
Heart disease is the leading cause
Cancer (trachea, bronchus, and lung) are second
75% of the brain's substance is fed by blood
Stroke facts
Most common cause of arterial stenosis is atherosclerosis
Intracranial disease is less common than extracranial in the US
Opposite for Asian and African origins
Rates of stroke
700,000 Americans will have had a stroke in 2006, 157,000 of them will die
Strokes cost about $43 million per year
Cerebral vascular accident (CVA)
Stroke brain cell infarction has occurred
Focal neurologic deficit
A focal neurological impairment of the functional capacity of that part of the brain
The deficit effect becomes the SYMPTOM of stroke or TIA
Stroke symptoms never resolve completely
A true stroke results in a permanent neurologic deficit
Acute stroke
Sudden onset of symptoms
Stroke in evolution
Symptoms come and go, unstable
Completed stroke
No progress or resolution of symptoms, stable
TIA (not CVA, results in a focal neurological deficit)
Average TIA lasts from seconds to 30 minutes
Symptoms always resolve in under 24 hours
Usually embolic from heart or carotid
TIA
Caused by temporary loss of blood supply
Permanent cell damage may occur if TIA lasts for hours
RIND - Reversible Ischemic Neurologic Deficit
Neurologic deficit that lasts longer than 24 hours with symptoms resolving in time, in a way similar to that of a TIA
Less than a week, less than three days
Invariably produces brain cell infarction
Uncontrollable risk factors
Age - increasing age
Sex - men over women, women are more likely to die from stroke
Heredity and Race - more likely if a family member has had a stoke. Africans have a higher risk of death, and Asians have a greater risk of intracranial generated stroke
Prior stroke or heart disease
Controllable risk factors
High Blood Pressure - atherosclerosis
Diabetes
Smoking
A fib - prevent clots with anticoagulants
Blood cholesterol
Obesity and inactivity
Excessive alcohol
Causes of ischemic stroke
Atherosclerosis
Heart embolus
Hypertension
Dissection
Prethrombotic
Vasospasm
Atherosclerosis
Intimal damage and collagen exposure
Severe stenosis damages the intima to rupture
Blood hemorrhages into the plaque (ulceration)
Collagen fibers exposed and a thrombus forms
TIA followed by CVA (stroke) in 33% of patients within 5 years
True
Embolus from the heart
Left atrium
A fib can dislodge thromboembolus
Previous MI
damage to endothelium stimulates thrombus formation
Bacterial endocarditis
Effects the mitral valve where a thrombus may form
Hypertension
Elevated blood pressure can contribute to heart disease
Worsens atherosclerosis of large arteries
Injures small vessels of kidney and brain - hyaline (glassy) arteriolar sclerosis
Advances to occlusion of arteriole and can cause infarction
Dissection
Occurs between vessel layers
Effects patients between 20 and 50
Caused by hypertension, trauma, and FMD
Occurs commonly distal to the bifurcation, below base of skull
Leads to hemorrhage and thrombus between endothelium and media - two distinct lumens
Prethrombotic States
Abnormalities in blood coagulation
Usually in veins
Also in arteries
Posterior branch is the...
Internal carotid artery
70-80% of CCA flow will pass through the ICA
The ECA has ___ branches
8 - outside the cranium
Anterior
Posterior
Medial
Terminal
Cervical portion of the ICA
Extracranial ICA
Petrous portion of the ICA
Carotid canal/foramen, enters the cranium
Cavernous portion of the ICA
Carotid siphon
Supraclinoid portion of the ICA
Terminal ICA at bifurcation
First ICA branch
Opthalamic Artery
-Lacrimal A branch
-Supraorbital A branch
-Frontal A branch
Lacrimal Artery
Anastomoses with branches of the middle meningeal artery (of the internal maxillary A)
Supraorbital Artery
Arises from the mid part of the opthalmic artery and passes through the supraorbital notch where it anastomoses with the frontal branch of the superficial temporal artery and the facial atery
Frontal Artery
Passes to the forehead where it anastomoses with branches of the superficial temporal artery and the facial artery
The ICA terminates by bifurcating into the...
Anterior cerebral and Middle cerebral arteries
Anterior cerebral artery
Passes above the optic nerve to the fissure between the two hemispheres, then around the Corpus Collosum where it gives blood to the frontal lobes
Vertebral arteries
Originate from the subclavian arteries
Pass into the sixth cervical vertebra
Goes into the foramen magnum where they join to form the basilar artery
Right is usually smaller than left vertebral
Intracranial vertebral artery
Gives off the posterior inferior cerebellar artery (PICA)
Circle of Willis includes
Anterior cerebral arteries
Middle cerebral arteries
Posterior cerebral arteries
Communicating arteries
The ICA is connected to the...
Posterior cerebral artery by the posterior communicating artery
General Cerebrovascular Considerations
Four main vessels feed the brain:
-Right and left ICAs
-Right and left vertebral arteries
Only the MCA, ACA, and PCA are considered main channels of the Circle of Willis
True
Alternate collaterals of the Circle of Willis make it possible for a patient to have unilateral or bilateral occluded ICAs, yet have no symptoms