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71 Cards in this Set
- Front
- Back
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3 disorders that affect the balance between brain volume and fixed boundaries of the skull:
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Edema, Expanding mass lesions, hydrocephalus
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Two types of cerebral edema:
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Vasogenic and cytotoxic
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______ _____ is the term for increase in brain volume caused by an absolute increase in cerebral tissue water content
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Cerebral edema
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Six conditions that could lead to cerebral edema:
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Anoxia/hypoxia
Ischemia Trauma Neoplasms Infx Intoxications |
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Type of edema characterized by an increase in extracellular fluid volume:
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Vasogenic edema
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How would you characterize lymphatic drainage in the brain?
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What lymphatic drainage?
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When severe enough what can vasogenic edema lead to?
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Cerebral herniation
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Type of edema characterized by swelling of all the cellular elements of the brain?
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Cytotoxic edema
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In the presence of acute cerebral insult, neurons, glia, and endothelial cells swell within minutes. Why is this?
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Due to failure of ATP-dependent ion (sodium and calcium) transport
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In the context of cytotoxic edema, what does increased intracellular calcium do?
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Activates phospholipases and the release of arachidonic acid, leading to the release of oxygen-derived free radicals resulting in brain damage.
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In general, two major classes of stroke
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Ischemic stroke (occlusion of blood vessels leading to ischemic necrosis)
& Hemorrhagic stroke (rupture of blood vessels resulting in hemorrhage in the brain) |
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How does the fatality rate of hemorrhagic stroke compare to that of ischemic stroke? Is hemorrhagic stroke more or less common?
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Hemorrhagic stroke is less common (20% versus 80% ischemic), but carries a much higher fatality rate
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Cerebral infarction leads to necrosis of all of the affected:
A. Neurons B. Glia C. Vessels D. All of the above |
D
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What is a red infarct?
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When lysis of an occluding thrombus or embolus results in reperfusion (after necrosis has occurred).
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What is the central core in an infarction?
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Area of total ischemia in which there is irreversible tissue necrosis
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What is a penumbra?
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A zone of borderline ischemic tissue which receives collateral circulation. Prompt restoration of circulation in the penumbra may prevent structural damage
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What is the window of opportunity for salvaging the penumbra? What happens if you miss this window?
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Window = 3-4 hours. If you're too late the penumbra merges with the necrotic core
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Following a cerebral infarction, which occurs first, cytotoxic edema or vasogenic edema? Which is more reversible?
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Following infarct, cytotoxic edema evolves over minutes to hours, while vasogenic edema takes hours to days develop. Also, cytotoxic edema is more reversible while vasogenic edema is irreversible.
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Following infarction, when is edema at its maximum?
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On the 3rd or 4th day
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Death from massive hemispheric infarctions is not usually caused by loss of brain tissue. Instead, what causes most death?
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Cerebral edema and herniations
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(T/F) During the first 24 hours following a stroke there is poorly demarcated areas of softening in the brain which is usually picked up by imaging techniques.
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False. While there is poorly demarcated areas of softening, imaging may entirely be negative
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At the peak of edema following a cerebral infarction, how does the infarction appear on a T-2 MRI image?
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At the peak of edema (3-4 days) the infarct appears hypodense and bright on T-2 MRI images.
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"What is the term for small infarcts (""Swiss cheese"") that occur in the deeper parts of the brain and brain stem?"
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Lacunar infarction
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Lacunar infarctions make up what percentage of all strokes?
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20%
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Following a ruptured saccular aneurysm, what would you see one week after the bleed? What about after that?
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Approx. one week later you'll see vascular spasms causing ischemic injury.
Later on , hydrocephalus may develop due to blockage of CSF flow due to subarachnoid clots. |
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(T/F) Most Arteriovenous malformations are congenital
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TRUE
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What are the most feared outcomes of Arteriovenous malformations (AVMs)
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Intracerebral and subarachnoid hemorrhage
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(T/F) Patients with AVM's have an increased risk of saccular (berry) aneurysms
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TRUE
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(T/F) Clinical outcomes of arteriovenous malformations (AVMs) include episodes of bleeding over many years, but rarely a single catastrophic bleed.
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FALSE - People with AVM's can experience both.
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Intracerebral hemorrhage is most likely to be caused by what?
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Hypertension
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When it comes to hypertensive intracerebral hemorrhages, what is the most likely cause/location?
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Bleeding from Charcot-Bouchard aneurysm most frequently found in basal ganglia or putamen
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What is the most likely cause of a lobar intracerebral hemorrhage?
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Usually not hypertensive, but instead caused by tumor, or amyloid angiopathy
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What are 4 common symptoms of an intracerebral hemorrhage?
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Headache
Nausea Vomiting Decr. Level of consciousness* * Most common Note that strokes can present the same way |
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If you are trying to diagnose a subarachnoid hemorrhage and a head CT is normal, what is the next step? What are you looking for?
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If a CT is normal, next do a lumbar puncture. You are looking for blood in the CSF
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What are two surgical techniques for fixing a subarachnoid hemorrhage?
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Cerebral angiography
Aneurysmal clipping/coiling |
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Although TIAs don't cause any permanent damage, why should you pay attention to them?
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They are a big warning sign for future strokes
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When it comes to TIAs, how long do transient deficits last for (according to USMLE)?
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According to USMLE deficits should last <24 hours, (although new evidence shows they should last for < 60 minutes)
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5 stroke symptoms that patients should be aware of:
This is a k-n-o-w |
SUDDEN numbness or weakness esp on one side of the body
SUDDEN confusion SUDDEN trouble seeing in one or both eyes SUDDEN trouble walking/ trouble with coordination SUDDEN severe headache with no known cause |
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Five major stroke syndromes for rapid recognition in the ED:
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Left (dominant) cerebral hemisphere
Right (nondominant) cerebral hemisphere Cerebellum Lacunar syndromes Brainstem *All occur suddenly |
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Symptoms of a stroke in the left (Dominant) cerebral hemisphere (5):
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Aphasia (inability to communicate)
L gaze preference R visual field deficit R hemiparesis R hemisensory loss |
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Symptoms of a stroke in the right (non-dominant) cerebral hemisphere (5)
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Neglect (Left side)
R gaze preference L visual field defici L hemiparesis L hemisensory loss |
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Symptoms of a stroke in the brainstem (lots)
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Hemi- or quadriparesis
Sensory loss in all four limbs Crossed signs (face versus limbs) Diplopia, dysconjugate gaze Vertigo Tinnitus Nausea/vomiting Hiccups, abnormal respirations Decr consciousness |
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Symptoms of a stroke in the cerebellum
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Truncal / gait ataxia
Limb ataxia |
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Symptoms of a stroke in the lacunar (small vessels)
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Pure motor hemiplegia (internal capsule or basis pontis)
Pure hemisensory loss (thalamic infarction) Sensorimotor (posterior limb of IC or ventral post thalamus) Ataxic hemiparesis (post limb of the IC or basis pontis) Clumsy-hand dysarthria (post limb of the IC or basis pontis) * in general these strokes affect deeper structures so the damage is more widespread |
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On the NIH stroke scale does a higher number mean more or less severity?
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More severity
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Criteria for intravenous tPA (3)
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Patient must be over 18
Patient must've had a clinical stroke <3 hours from time of onset |
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Suppose I went to bed at midnight feeling perfectly normal. During the night, I got up at 4:00 AM to get a drink of water (still feeling normal). Then, when I woke up at 8:00 to get ready for class I noticed unexplained right sided weakness. What is my time of onset for the stroke I just had?
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Four hours. The time is based on when I last felt normal.
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What is the big concern with using tPA to treat a stroke?
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Intracerebral hemorrhage
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Why should you be concerned about over-aggressive treatment of hypertension in patients with an acute cerebral infarction?
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The small vessels in the brain are great at controlling blood flow over a wide range of pressures. Strokes damage this autoregulation, so dropping the pressure suddenly can cause a drop in profusion to the brain.
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How does ANCROD (snake venom) work in treating a stroke?
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It is a defibrinogenting agent
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One future treatment being considered for stroke is combining IV tPA with intra-arterial tPA. What have initial studies shown regarding the outcomes of this treatment?
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Initial studies have shown this treatment to be promising. (A phase III trial is planned)
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One future treatment being considered for stroke is combining trans-cranial Doppler with IV tPA. The idea is that ultrasound helps disrupt the thrombus. Was the first trial encouraging or discouraging?
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Encouraging.
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What is a mercy retriever?
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A coil-like device that allows surgeons to go up intravascularly and pull out a thrombus. It's like a roto-rooter for the brain!
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What are two major risk factors for lacunar infarctions?
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Hypertension, diabetes
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Lacunar infarctions are caused by occlusion of which arteries?
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Occlusions of deep penetrating branches of major cerebral arteries
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How does the severity of lacunar infarctions compare with larger hemispheric infarctions?
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Lacunar infarctions can be as severe as larger infarcts but they are less life-threatening as larger ones since they aren't followed by cerebral edema.
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Seven(!) causes of ischemic infarctions:
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Arthrosclerosis of large arteries w/ and w/o thrombosis
Hyaline arteriolosclerosis (lipohyalinosis) narrowing of small arteries due to hypertension and diabetes Emboli Trauma causing dissecting aneurysms and other lesions Contraceptives and estrogen therapy (venous thrombosis mostly) Vascular spasm - complication of subarachnoid hemorrhage Vasculitis/hematologic/metabolic disorders |
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Risk factors for venous infarction:
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Hypercoagulable state
Extrinsic compression of a venous sinus by tumor or infection Low flow state within sinus Dehydration Pregnancy & postpartum As many as 25% of venous infarcts occur with no predisposing risk factors |
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Venous infarctions frequently are _____ and occur within the white matter or at the ______-_______ _____ ______
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Most commonly hemorrhagic and occur within the white matter or the gray-white matter junction
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Do transient ischemic attacks cause permanent tissue damage?
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NO!
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Major causes of hemorrhagic stroke?
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Hypertensive intracerebral hemorrhage
Ruptured arterial aneurysms Arteriovenous malformations |
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Which type of stroke results in hematoma formation and subarachnoid hemorrhage?
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Hemorrhagic stroke
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What is the most common location for a hypertensive intracerebral hemorrhage to occur?
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Basal ganglia & thalamus (65%)
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What is a saccular (Berry) aneurysm? Where do they usually occur?
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A thin-walled outpouching at an arterial branch point
The majority of them are on the circle of willis and the branch points of the middle cerebral artery |
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What percentage of adult autopsies are nonruptured berry aneurysms found?
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Nonruptured berry aneurysms are found in 2% of adult autopsies
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(T/F) The majority of berry aneurysms are found in people with polycystic kidney disease, Ehlers-Danlos, NF-1, & Marfan syndrome.
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False! The majority of berry aneurysms occur sporadically, although there is an increased risk of getting them in those conditions.
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How can an unruptured Saccular (berry) aneurysm cause symptoms?
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By compressing cranial nerves, vessels, and brain tissue
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What is the sac of Saccular (berry) aneurysms made of?
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Thickened hyalinized intima
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The vessels bearing saccular (berry) aneurysms are located in where?
A. Subdural space B. Subarachnoid space C. Intraventricular D. Intracerebral |
B. Subarachnoid space
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In addition to subarachnoid hemorrhage, a ruptured saccular aneurysm can cause blood to spurt out with a force that can tear the soft brain resulting in both ______ and ______ hemorrhage
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A ruptured saccular aneurysm can cause intracerebral and intraventricular hemorrhage
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What is the clinical hallmark of a subarachnoid hemorrhage?
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Worst headache ever! (W/out neural deficits)
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