Path of Cerebrovascular Disease & Stroke (Bambach & Pieper) Flashcards
these two neuron populations are especially vulnerable to global ischemia/hypoxia
hippocampus neurons and Purkinje neurons in the cerebellum
this is the most common disease process responsible for thrombosis or embolism
atherosclerosis
what structural damage would you expect from a partial thrombus of the MCA, involving primarily the lenticulstriate branches?
infarct confined to the basal ganglia/thalamic nuclei
what is the disease process behind the picture shown below?
this is a cholesterol embolus - you can tell because of the spicule-like clear spaces, which represent cholesterol clefts that were left behind during the lipid extraction/processesing of this sample; so we know this is from an atherosclerotic plaque
this type of infarct in the brain is usually due to thrombus and results in no reperfusion of the ischemic tissue
non-hemorrhagic
this type of infarct in the brain is usually due to an embolus and results in reperfusion of all or part of the ischemic tissue
hemorrhagic
All of the following are changes associated with acute stage infarct EXCEPT:
A. Coagulation necrosis
B. Axonal degeneration
C. Cerebral edema
D. Vascular proliferation
E. Reactive gliosis
F. Neutrophil response
E. This is a change associated with the subacute stage (~1-4 weeks after initial insult)
these two changes dominate the subacute stage of infarct
marcophages & reactive gliosis (gemistocytes)
cyst formation and glial scarring characterize the ____ stage of tissue infarct, occuring ~5 weeks after the initial insult
remote
why is white matter in the infant brain especially susceptible to asphyxia?
because oligodendrocytes are busy myelinating axons, which increases their metabolic activity making them more vulnerable to anoxic injury
*their neurons, on the other hand, are relatively resistant to anoxic-hypoxic injury
this can be thought of as a meltdown of whte matter adjacent to the ventricles in term infants that have undergone asphyxia:
periventricular leukomalacia
where do most hypertensive hemorrhages arise in the brain?
basal ganglia/thalamus (2/3)
*the rest arise in the pons and cerebellum
these aneurysms typically arise at branch points in or near the major arteries that form the Circle of Willis, and when they rupture, bleeding is usually confined within the subarachnoid space at the base of the brain
saccular (berry) aneurysms
most saccular aneurysms arise in the _____ circulation, with the majority arising at the branch point between the ______ and the _______.
anterior circulation; most arise between the ACA and the anterior communicating artery
what vascular malformation is shown below that may result in stroke-like episodes due to local ischemia of surrounding tissue as the result of a ‘steal’ phenomenon?
arteriovenous malformation (AVM)
this type of hemorrhage involves primarily the white matter, sparing of the adjacent deep gray structures (in contast to spontaneous hypertensive hemorrhages)
lobar intraparenchymal hemorrhage (of amyloid angiopathy)
Which is more common: ischemic or hemorrhagic stroke?
ischemic; with arterial occlusion more common than venous.
Which of the following statements about stroke is TRUE?
A. Most of the time, ischemic stroke is due to a venous occlusion
B. Symptoms of stroke correlate to a specific lobe
C. Ischemic stroke does not include cases of global ischemia
D. Though the presenation of stroke differs by case, the mechanism is always the same
E. The rapidness of loss of function during stroke depends on how much energy is stored in that particular brain
C. Global ischemia is caused by something more like cardiac arrest.
A - ischemic stroke is usually due to an arterial occlusion
B - symptoms correlate to the vascular territory, not exclusively to a single lobe
D - there are multiple mechanisms of stroke (ie occlusion, hemorrhage, compression, etc)
E - the brain does not maintain energy reserves - there is no energy storage
cerebral metabolism depends on aerobic or anaerobic metabolism?
aerobic; astrocytes use glucose for glycolysis to make lactate, which is taken up and oxidized by the mitochondria in the neurons to make fuel for oxidative phosphorylation
All of the following are metabolic consequences of ischemia, leading to loss of control of electrolyte gradients and cell death, EXCEPT:
A. Cellular influx of Ca++ and K+, efflux of Na+
B. Increased intracellular water
C. Release of free radicals that activate apoptotic genes
D. Increased activity of phospholipases, proteases, and endonucleases
E. Depolarized external membrane
A. There is an influx of Na+ in and efflux of K+ out of the cell.
type of stroke that affects the large vessles
atherothrombotic (25% of all strokes)
type of stroke that affects the small vessels
lacunar (25% of all strokes)
type of stroke arising from afib or structural heart disease
cardioembolism (25% of all strokes)
a stroke of this large vessel will present with behavior change and leg weakness
ACA
A stroke of this large vessel will present with lack of awareness of the problem (anosognosia), left neglect, left sided weakness, right gaze deviation (injury to the right frontal eye field) and quadrant/or hemianopsia
Right MCA
A stroke of this large vessel in a right-handed patient will present with aphasia, right sided weakness, left gaze deviation, quadrant/or hemianopsia
left MCA
in _____ artery occlusion, the reticular formation is involved and thus the patient will present with coma
basilar
occlusions of this artery will not produce “cortical” signs as there is typically redundant flow from its contralateral counterpart to the rest of the posterior circulation - will instead see incoordination, vertigo, nystagmus, Wallenberg or locked in syndrome
vertebral
- wallenberg= lateral medulla stroke
- locked-in syndrome = medial medulla stroke
- unilateral uncoordination = PICA stroke
A stroke in this large vessel will present with hemi-visual field loss (homonymous hemianopsia)
PCA
classic lacunar stroke, presents with no cortical signs or symptoms, instead:
- ipsi facial numbness, incoordination, Horner’s
- contra body numbness
- hiccups, hoarseness, dysphagia
- vertigo and nystagmus
wallenberg syndrome (lateral medullary syndrome)
All of the following are hallmark features of small vessel strokes (lacunar syndromes) EXCEPT:
A. Pure motor weakness
B. Pure sensory loss
C. Diplopia
D. Disturbance of consciousness
E. Vertigo
D. Unlike the “large vessel” stroke of the basilar artery, the lacunar stroke involving the small vessels off the basilar will not be sufficient to injure the reticular formation
______ and ______ are acute onset “stroke mimics” that should be considered when determining the cause of injury
hypoglycemia and seizure
*migraine is also a possibility but should only be considered after other causes are ruled out - it is a diagnosis of exclusion
treatment of emoblic stroke, though may be sensitive as early treatment may worsen intraparenchymal bleeding after ischemic stroke (hemorrhage transformation)
anticoagulation therapy
most common cause of intraparenchymal hemorrhage
hypertension, leading to breakage of the perforator arteries
*may also be caused by tumor, drugs, infection, vessel malformations, and coagulopathies
All of the following are common locations for hypertensive hemorrhage EXCEPT:
A. Putamen
B. Caudate
C. Thalamus
D. Pons
E. Cerebellum
B. Only on the rare occasion will the Caudate be involved.
True or False: Rapid and strict control of blood pressure is the best treatment for a hypertensive brain bleed.
False. A hemorrhage will continue to grow despite efforts to control blood pressure. Initial treatment of hemorrhagic stroke includes an aneurysm clip if it is in the subarachnoid, an intraventricular drain if there is hydrocephalus, and blood pressure control for intraparechymal bloeeding. Mostly supportive care is needed, as after 24 hours the bleeding will tamponade against the surrounding tissue and eventually clear.
headache, nausea/vomiting, pinpoint pupils, and coma all point to a hemorrhagic stroke where?
pons
headache, nause/vomiting, vertigo and coma all point to a hemorrhagic stroke where?
cerebellum
*cerebellar and pontine hemorrhages occur in the posterior fossa, so of particular concern is herniation and increased ICP. If the reticular formation becomes injured, this is a neruologic emergency and typically requires airway and ICP control, perhaps ventricular drainage placement.
secondary periclot neuronal injury in the form of edema ~24-48 hours after hemorrhagic stroke is though to occur via what mechanism?
breakdown of BBB and accompanying inflammatory response to breakdown products
67 yo right-handed man has sudden right sided weakness while driving. When found by paramedics, he cannot produce words, but seems to comprehend what is spoken to him. He has left gaze deviation, right homonymous hemianopsia and right hemiparesis. BP is 180/90 and HR is irreg irreg in the 100s. Where, what, and why is this lesion?
Where: Left hemisphere - L gaze deviation, aphasia, right visual field loss, right hemiparesis
What: Ischemic stroke, embolus, left MCA
Why: A fib -irreg irreg HR
74 yo Caucasian man found at home by family at 6 pm. He was last seen normal that morning. He is noted to have left sided weakness and is looking to the right. He does not think there is anything wrong with him. He is a diabetic and a smoker. BP 145/78, HR 85 and regular. He cannot recognize his left hand, he thinks its yours. He does not bleieve that there is anything wrong with him. He has left gaze deviation and left VF loss, as well as left hemiparesis. Where, what and why is this lesion?
Where: right hemisphere
What: ischemic stroke, right MCA
Why: large vessel athersclerosis (smoking, DM, ethnicity) or possibly occlusion
A 55 yo man was at work when he was suddenly witnessed by his coworkers to wince and grip his head. He then collapsed. Paramedics on the scene note pinpoint pupils and poor respiration. He was immediately intubated and taken to the closest medical facility. Familly members share that he has a history of hypertension and recently stopped his meds. BP is 260/135, HR 45, comatose. Where, what and why is this lesion?
Where: pons - coma with pinpoint pupils
What: hemorrhage - headache, hypertension, sudden onset
Why: hypertensive hemorrhage
Which of the following is NOT part of the acute therapy for ischemic stroke?
A. ivTPA window is 4.5 hours for all patients
B. the goal for ivTPA is 45 minutes “door to needle”
C. For patients who have a defined clot in the larger cerebral vessels, a paired treatment with intra-arterial approach may be offered.
D. After emergent stabilization and treatment with tpa, the patient should be admitted to a primary stroke or comprehensive stroke center.
A. Currently this is only for patients under 80. It is otherwise thought to be too risky for bleeding.
