Brain Aneurysms & AV Malformations
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Transcript of Brain Aneurysms & AV Malformations
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Brain Aneurysms
and
AV Malformations
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Brain Circulation
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Brain Circulation
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Arterial Circulation in the Brain
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Circle of Willis
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Cerebral Arteries
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Cerebral Angiography
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Venous Drainage
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Cerebral Spinal Fluid Drainage
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Cerebral Spinal Fluid
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Cerebral Spinal Fluid
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The Human Brain
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Aneurysm
• The word aneurysm comes from the Latin word aneurysma, which means dilatation.
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Types of Aneurysms
• Saccular aneurysm– Occurs at bifurcations
• Fusiform aneurysm– Commonly in basilar
artery
• Dissecting aneurysm
• Ruptured aneurysm
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Aneurysm Types
Saccular
Fusiform
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Large Aneurysm
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Cerebral Aneurysms• Cerebral aneurysms usually occur at the
bifurcations and branches of the large arteries located at the Circle of Willis.
• The most common sites include the:– Anterior Communicating artery (30 - 35%)
– Bifurcation of the Internal Carotid and Posterior Communicating artery
(30 - 35%)– Bifurcation of Middle cerebral (20%)– Basilar artery bifurcation (5%)– Remaining posterior circulation arteries (5%)
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Risk Factors for Aneurysms
• Smoking• Hypertension• Polycystic kidney disease 15% have aneury• Coarctation of the aorta• Anomalous vessels• FMD• Connective tissue disorders (eg, Marfan,
Ehlers-Danlos)• High-flow states (eg, vascular malformations,
fistulae)• Spontaneous dissections/Trauma
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Signs & Symptoms of Brain Aneurysms
• Usually asymptomatic until rupture
– Cranial Nerve Palsy
– Dilated Pupils
– Double Vision
– Pain Above and Behind Eye
– Localized Headache
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“Warning Signs” of Brain Aneurysms
• Warning signs prior rupture
– Localized Headache
– Nausea & Vomiting
– Stiff Neck
– Blurred or Double Vision
– Sensitivity to Light (photophobia)
– Loss of Sensation
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Treatment of Brain Aneurysms
• Surgery– craniotomy and clipping of aneurysm
• Endovascular coiling
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Aneurysm Post-Op Risks• Rebleeding
– Most frequently within the first 24 hours– Up to 20% of patients rebleed within 14 days– Main preventative measure is control of blood pressure
(preferably beta blockers)
• Vasospasm– Usually occurs before 3 days or after 10 days (post bleed)– May require hyper-volemic therapy
• Hydrocephalus• Hyponatremia• Fluids / Electrolytes
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Arterio-Venous Malformation
(AVM)• Arteriovenous malformation (AVM) of the brain is a
"short circuit“ between the arteries and veins.
• Normally the connection between arteries and veins is through a network of smaller vessels (capillaries) which slow the blood down and permit the exchange of food, oxygen and nutrients into the tissues.
• In arteriovenous malformations, the arteries and veins have a direct connection, bypassing the capillary network.
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Arterio-Venous Malformation (AVM)
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AVM
• Arteriovenous malformation of the brain presents later in childhood or, more frequently, in adults in the second to third decade of life.
• AVMs present with seizures, hemorrhage, progressive neurological dysfunction or headaches
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Complications of AVM’s
• Hemorrhage (into surrounding tissue)
• Ischemia
• Seizures
• Brain Cell Death
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Signs & Symptoms of AVM’s
• Seizures
• Headaches
• “Whooshing" Sound (bruit)
• Other Signs – Subtle behavioral changes – Communication or thinking disturbances – Loss of coordination and balance
– Paralysis or weakness in one part of the body – Visual disturbances – Abnormal sensations
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Diagnosing AVM’s
• MRI (including MR Angiography) as well as CT Angiography are among the initial neuro-imaging tests that help identify these problems.
• Cerebral Angiography is a prerequisite to accurately and definitively identify the precise anatomy and configuration of both the lesion as well as the feeding and draining vessels
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Treatment of AVM’s
• Surgery
– usually delayed
– open ligation and/or resection of the AVM
• Radiosurgery
• Embolization
– usually as adjunct to surgery
• Observation
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Radiosurgery
• Believed to "work" by initiating an "inflammatory" response in the pathological blood vessels ultimately resulting in their progressive narrowing and ultimate closure
• The risk for hemorrhage is not reduced during this lag time
• There is the added risk of radiation necrosis of adjacent healthy brain tissue or brain cyst formation
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Radiosurgery• Advantages:
– Noninvasive
– Can access all anatomic locations of the Brain
• Disadvantages:
– Can only treat smaller lesions (<3 cm in diameter)
– Requires 2 or more years to complete
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AVM Post-Op Risks
• Perfusion-breakthrough bleeding
• Endovascular occlusion
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Brain Aneurysms & AVM’s
• Patients with AVMs have an increased risk of developing an intracranial aneurysms
• Aneurysms are often found on arteries feeding the AVM.
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Intracranial Hemorrhage (ICH)
• Epidural
• Subdural
• Subarachnoid
• Intraparencymal
• Intraventricular
• Cerebellar
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Treatment of ICH
Two key concepts:1) Intracranial Pressure
– Elevated when ICP >20 mm Hg
2) Cerebral Perfusion Pressure– CPP = MAP - ICP– Must maintain CPP > 70 mm Hg– Example: MAP = 100, ICP = 20 CPP = 80 mmHg
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Treatment of ICH• ICH is a dynamic, not a static process
• Hemorrhage volume can increase over time
• CT scan is the most important tool in your diagnostic toolbox
• Managing blood pressure is very important
• Must aggressively manage fever and seizures
• Consider hyperventilation and paralytics in setting of increased ICP and deterioration
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Subarachnoid Hemorrhage (SAH)
• SAH may be spontaneous or traumatic
• Spontaneous SAH are caused by– Cerebral aneurysms
– AV malformations
• Uncommon causes – neoplasms, AVM’s, venous angiomas, infectious aneurysms
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SAH• Warning bleeds” are relatively common
• Sentinel headache 30-50%
• Early diagnosis prior to rupture will improve outcomes
• Unusual headache
• 50% of patients die within 48 hours irrespective of therapy
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SAH• Often accompanied by a
period of unconsciousness (50% never wake up)
• Common signs include neck stiffness, photophobia, headache
• 20% have ECG evidence of myocardial ischemia
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Complications of SAH
• Hydrocephalus may develop within the first 24 hours because of obstruction of CSF outflow in the ventricular system by clotted blood.
• Rebleeding of SAH occurs in 20% of patients in the first 2 weeks. Peak incidence of rebleeding occurs the day after SAH. This may be from lysis of the aneurysmal clot.
• Vasospasm from arterial smooth muscle contraction (symptomatic in 36% of patients).
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Hydrocephalus After SAH
• Caused by obstruction of CSF flow by clotted blood
• Must be careful with drainage – a reduction in ICP can increase the risk of rebleeding
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Rebleeding After SAH
• Rebleeding occurs most frequently within the first 24 hours
• Up to 20% of patients rebleed within 14 days
• The main preventative measure is to control the blood pressure – preferably beta blockers
• Alternatively early clipping of the aneurysm allows hypertensive and hypervolemic therapy to prevent vasospasm
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Vasospasm After SAH• Worst time is day 7 to day 10 (most
frequent time for vasospasms)
• Diagnosed by neurologic exam, transcranial doppler and angiography
• May use calcium channel blockers
– Reduce vasospasm, neurological deficit, cerebral infarction and mortality
• May use some antispasmodics
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Vasospasm HHH Therapy
• Hemodilution– Hct 30-35%
• Hypertension– Phenylephrine /
Norepinephrine
– BP titration to CPP/exam
• Hypervolemia– Colloids/crystalloids
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Other Vasospasm Therapy• Angioplasty
– BP management during procedure
– Reperfusion issues
– Timing
• Papaverine Infusion
– Side effects
– Repeated trips
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Other Complications of SAH
• Neurologic deficits from cerebral ischemia, peaks at days 4-12.
• Hypothalamic dysfunction causes excessive sympathetic stimulation, which may lead to myocardial ischemia or labile detrimental BP.
• Hyponatremia may result from cerebral salt wasting / SIADH
• Nosocomial pneumonia and other complications of critical care may occur.
• Pulmonary edema – neurogenic & nonneurogenic
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Treatment of SAH’s
1) Identifying and treating the causative lesion, thus preventing re-bleeding
2) Treating hydrocephalus
3) Treating and preventing vasospasm
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Treatment of SAH’s
• Maintain systolic BP >130mmHg
– Use vasopressors if necessary to maintain CPP and reduce ischemic complications from vasospasm
• Generally avoid vasodilators (except calcium channel blockers)
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Brain Hemorrhage
Sudden onset of “the worst headache of my life”
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The End
Thank You