Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
patho exam 3
disorders of circulation of CNS
| Question | Answer |
|---|---|
| major components of CNS | brain and spinal cord |
| job of the CNS | detect, transmit, analyze sensory information generate signals to autonomic and motor pathways that orchestrate visceral and endocrine functions, coordination, movement |
| tissues of CNS rely heavily on receiving constant perfusion | cerebral autoregulation blood-brain barrier |
| major disorders | transient ischemic attack (TIA) stroke subdural and spinal cord hemorrhage |
| tia | brief appearance of symptoms resembling stroke generally resolve within 24 hours |
| stroke | brain attack enduring disruption of speech, motor, communication accompanied by cognitive deficits |
| Disorders of circulation within brain | revolve around lack of oxygen and increased pressure within skull |
| ischemia | Obstructed blood vessels Drop in blood flow to brain |
| increased pressure within skull | Hematoma Excessive production of CSF Blockage of duct system conveying CSF |
| brain | 2.5% of total body mass, receives 15% of the cardiac output |
| gray matter | uses 94% of cerebral oxygen |
| white matter | 60% of brain mass, uses 6% of cerebral oxygen |
| maintenance of cerebral circulation | Right and left internal carotid arteries Right and left vertebral arteries |
| blood brain barrier | Specialized endothelium present in brain capillaries |
| BBB permits selective entry of substances because of | Tight junctions between endothelial cells Few pinocytotic vesicles No fenestra Active transport |
| substances that cross barrier | Highly lipophilic substances cross directly Most nutrients cross barrier by facilitated |
| regions of brain lacking BBB | Subfornical organ and area postrema of brainstem Infundibulum of hypothalamus and pituitary gland |
| cerebral autoregulation | Mechanism that maintains steady flow of blood to brain and spinal cord |
| cerebral blood flow: arteries respond to | pH, carbon dioxide, oxygen |
| increased BP | constricted cerebral capillaries |
| decreased BP | dilated capillaries |
| Decreased PaCO2 levels | constricted cerebral vessels |
| Increased PaCO2 levels | dilated cerebral vessels |
| Autoregulatory mechanisms fail | Loss of match between oxygen supply and demand of tissues |
| Intracranial pressure helps control | mechanism by which blood is controlled in the brain Monro-kellie hypothesis |
| Monro-kellie hypothesis | Compensatory relationship maintaining cerebral compliance in response to changes in volume |
| Injured brain tissue | Cytotoxic edema (damage of cells in the brain) Vasogenic edema Clearance of brain tissue swelling |
| Hydrocephalus | Excessive accumulation of CSF in cranial vault Compresses surrounding structures Causes: lesions that obstruct flow of CSF, problems with resorption |
| Brain receives how much cardiac output | 15% of cardiac output |
| Brain uses how much of body's oxygen | 20% of body’s oxygen consumption |
| cerebral blood flow | Autoregulation Blood viscosity Cerebral vascular resistance (CVR) Cerebral perfusion pressure (CPP) |
| CBF = | CPP/CVR |
| Concurrent ischemia and hypoxia due to | mitochondrial dysfunction, energy deprivation and loss of ion homeostasis, cerebral hemorrhage in sepsis |
| Mitochondrial dysfunction | Leads to infarction and tissue death Anaerobic glycolytic pathways initiated |
| Energy deprivation and loss of ion homeostasis | Cells unable to maintain negative membrane potential Excitatory amino acids in extracellular space Glutamate and influx of calcium ions Induces apoptosis |
| cerebral hemorrhage in sepsis | Immune cells activated Leukocytes enter brain Inflammatory agents contribute to brain inflammation Nitric oxide/nitric oxide synthetase pathway Mitochondrial dysfunction and apoptosis - ESSENTIAL |
| Transient Ischemic Attack (TIA) | Similar to angina Temporary episode of neurologic dysfunction Caused by focal brain, spinal cord or retina ischemia without acute infarction |
| etiology and pathogenesis of tia | Same as ischemic stroke Clot blocking blood supply to region of brain Atherosclerosis First sign of a stroke!! |
| TIA nonmodifiable risk factors | age, family history, prior TIA or stroke, race, sex, sickle cell diseas |
| TIA modifiable risk factors | cardiovascular disease, carotid artery disease, diabetes, excess weight, high BP, high cholesterol, cigarette smoking, heavy drinking, physical inactivity, poor nutrition, use of birth control pills |
| CMs of TIA | Facial drooping Arm or leg weakness on one side of body Speech difficulty Sudden trouble seeing in one or both eyes Difficulty walking with dizziness Lack of balance or coordination Severe headache |
| treatment and diagnosis of TIA | Exclusion of conditions that mimic TIA Blood glucose and other blood tests Electrocardiography Noncontrast CT MRI with diffusion-weighted imaging CT angiography or magnetic resonance angiography Carotid doppler |
| how do you treat TIA | treat what is causing the formation of atheroma |
| Ischemic and Hemorrhagic Stroke: Stroke | Interruption in blood supply to region of brain or bleeding of vessel resulting in brain tissue damage or infarction |
| ischemic stroke | 87% |
| hemorrhagic stroke | 13% - disruption of arteries make blood move to interstitial space |
| Etiology and pathogenesis: ischemic stroke | Partial or complete occlusion of cerebral blood flow due to thrombus or embolus Atherosclerosis Cardiac disorders Thrombotic strokes |
| Thrombotic strokes | Internal carotid artery Middle cerebral artery Basilar artery |
| Etiology and pathogenesis: hemorrhagic stroke | Bleeding into brain from blood vessel Subarachnoid hemorrhage Cerebral aneurysm Arteriovenous malformation (AVMs) |
| types of bleeding into brain from blood vessel | Intracerebral Intraventricular Extracerebral |
| Ischemic and Hemorrhagic Stroke: CMs | Sudden onset of focal neurologic deficit persisting for at least 24 hours due to reduction or occlusion of cerebral circulation or rupture of blood vessels Other signs and symptoms depending on area of brain or spinal cord affected |
| treatment of ischemic stroke | Restoration of blood flow and reducing area of infarction Penumbra: tissue surrounding infarction Supplemental oxygen Glycemic control Fibrinolytic therapy Antihypertensive therapy Aspirin 325 mg Hypothermia |
| treatment of hemorrhagic stroke | Osmotic diuretics Surgical evacuation Craniotomy with aneurysm clipping Endovascular therapy with coil embolization Delayed cerebral ischemia (DCI) |
| subdural hematoma | Bleeding from bridging veins between dura mater and arachnoid membrane |
| Etiology and pathogenesis of subdural hematoma | Trauma from high-speed impact to skull Spontaneous Acute subdural hematoma: bleeding identified immediately after an injury Chronic subdural hematoma: brain atrophy |
| CMs of subdural hematoma | Headache Confusion, changes in behavior Dizziness Nauseous, vomiting Lethargy or excessive drowsiness, weakness Apathy Seizures |
| treatment of subdural hematoma | surgery |
| spinal cord hemorrhage | Hemorrhage of spinal cord, rare |
| Etiology and pathogenesis: spinal cord hemorrhage | Trauma, vascular malformation, bleeding disorders Epidural, subdural, subarachnoid, or intramedullary: intramedullary hemorrhage (hematomyelia), epidural and subdural spinal cord hemorrhage |
| CMs of spinal cord hemorrhage | Sudden, severe back pain with or without radiculopathy Headache Neck stiffness Photosensitivity Irreversible sensory loss below level of bleed |
| Treatment of spinal subdural hemorrhage | surgical decompression |
| treatment of spinal subarachnoid hemorrhage | Surgical resection Catheter-based interventional techniques Focal radiation therapy with gamma knife, cold photon knife |
Created by:
leh195