{"id":5471,"date":"2025-12-09T14:40:58","date_gmt":"2025-12-09T19:40:58","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/?post_type=chapter&#038;p=5471"},"modified":"2025-12-09T23:17:21","modified_gmt":"2025-12-10T04:17:21","slug":"increased-intracranial-pressure-icp-cushings-reflex-and-brain-herniations","status":"web-only","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/chapter\/increased-intracranial-pressure-icp-cushings-reflex-and-brain-herniations\/","title":{"raw":"11p12  Increased Intracranial Pressure (ICP), Cushing's Reflex, and Brain Herniations","rendered":"11p12  Increased Intracranial Pressure (ICP), Cushing&#8217;s Reflex, and Brain Herniations"},"content":{"raw":"<h1><strong>Causes of Increased ICP<\/strong><\/h1>\r\n<ul>\r\n \t<li><strong>Trauma<\/strong>,\u00a0<strong>tumors<\/strong>,\u00a0<strong>hemorrhage<\/strong>.<\/li>\r\n \t<li><strong>Inflammation<\/strong>\u00a0or\u00a0<strong>infection<\/strong>.<\/li>\r\n \t<li><strong>Obstruction of cerebrospinal fluid (CSF) drainage<\/strong>:\r\n<ul>\r\n \t<li>CSF is produced in the brain\u2019s ventricles and drains into the jugular vein.<\/li>\r\n \t<li>Blockage causes CSF accumulation, increasing volume and pressure.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<h1><strong>Pathophysiology of ICP<\/strong><\/h1>\r\n<ul>\r\n \t<li><strong>Normal<\/strong>: Brain, blood, and CSF are within a\u00a0<strong>rigid skull<\/strong>.<\/li>\r\n \t<li><strong>Increase<\/strong>\u00a0in fluid (blood, CSF, edema) raises\u00a0<strong>pressure<\/strong>.<\/li>\r\n \t<li><strong>Brain tissues<\/strong>\u00a0are\u00a0<strong>pressure-sensitive<\/strong>\u00a0and can become ischemic if pressure cuts off blood flow.<\/li>\r\n<\/ul>\r\n<h1><strong>Body\u2019s Compensation for Increased ICP<\/strong><\/h1>\r\n<ul>\r\n \t<li><strong>Initial response<\/strong>:\r\n<ul>\r\n \t<li><strong>Shifting CSF<\/strong>\u00a0from ventricles into the spinal canal to reduce intracranial volume.<\/li>\r\n \t<li>Results in\u00a0<strong>ventricle shrinking<\/strong>.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Cerebrovascular Vasodilation<\/strong>:\r\n<ul>\r\n \t<li>Local\u00a0<strong>hypoxia<\/strong>\u00a0causes\u00a0<strong>nitric oxide<\/strong>\u00a0release, dilating vessels.<\/li>\r\n \t<li>Temporarily\u00a0<strong>increases blood flow<\/strong>\u00a0to brain to compensate.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Vasoconstriction<\/strong>:\r\n<ul>\r\n \t<li>Increased volume and pressure lead to <strong>pinching <\/strong>off of<strong> brain capillaries.<\/strong><\/li>\r\n \t<li>Reduced\u00a0<strong>cerebral blood flow<\/strong>, worsening\u00a0<strong>ischemia<\/strong>.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<strong>Worsening Condition<\/strong>\r\n<ul>\r\n \t<li>Persistent ICP causes\u00a0<strong>capillary constriction<\/strong>, decreasing\u00a0<strong>oxygen supply<\/strong>.<\/li>\r\n \t<li>Brain becomes\u00a0<strong>hypoxic<\/strong>.<\/li>\r\n \t<li>The\u00a0<strong>medulla oblongata<\/strong>\u00a0triggers\u00a0<strong>Cushing\u2019s reflex<\/strong>.<\/li>\r\n<\/ul>\r\n<h1><strong>Cushing\u2019s Reflex (Triad)<\/strong><\/h1>\r\n<ul>\r\n \t<li><strong>Triggered<\/strong>\u00a0by brain ischemia.<\/li>\r\n \t<li><strong>Goal<\/strong>: Maintain blood flow to brain but often worsens ICP.<\/li>\r\n<\/ul>\r\n<strong>Cushing\u2019s Triad: Classic Signs of Increased ICP:<\/strong>\r\n<ol>\r\n \t<li><strong>Systemic hypertension<\/strong>:\r\n<ul>\r\n \t<li>Increased <strong>systolic blood pressure<\/strong>\u00a0(fight or flight response).<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Bradycardia<\/strong>:\r\n<ul>\r\n \t<li><strong>Slowed heart rate<\/strong>\u00a0(baroreceptor reflex in carotid arteries).<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Reduced respiration rate<\/strong>:\r\n<ul>\r\n \t<li>Hypoxia and low CO<sub>2<\/sub> levels reduce\u00a0<strong>respiratory drive<\/strong>.<\/li>\r\n \t<li>Leads to <strong>hypoventilation, hypoxia<\/strong>,\u00a0<strong>hypercapnia<\/strong>\u00a0exacerbates injury.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ol>\r\n<strong>Pathophysiology of Cushing\u2019s Triad<\/strong>\r\n<ul>\r\n \t<li>Brain ischemia triggers\u00a0<strong>sympathetic activation<\/strong>\u00a0\u2192 vasoconstriction \u2192 high blood pressure.<\/li>\r\n \t<li>Baroreceptors detect high pressure \u2192\u00a0<strong>reflex bradycardia<\/strong>.<\/li>\r\n \t<li>Increased ICP reduces\u00a0<strong>CO\u2082<\/strong>\u00a0levels (<strong>hypocapnia<\/strong>) \u2192\u00a0<strong>respiratory depression<\/strong>.<\/li>\r\n<\/ul>\r\n<h1><strong>Outcomes and Risks<\/strong><\/h1>\r\n<ul>\r\n \t<li><strong>Temporary<\/strong>\u00a0increase in blood flow\u00a0<strong>relieves<\/strong>\u00a0ischemia briefly.<\/li>\r\n \t<li><strong>Vicious cycle<\/strong>:\r\n<ul>\r\n \t<li>Increased pressure \u2192 more ischemia \u2192 further brain damage.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Progression<\/strong>:\r\n<ul>\r\n \t<li>Decreased neuronal function.<\/li>\r\n \t<li>Unresponsive coma.<\/li>\r\n \t<li>Potential\u00a0<strong>brain death<\/strong>\u00a0if ICP persists.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<strong>Consequences of Unmanaged ICP<\/strong>\r\n<ul>\r\n \t<li><strong>Progressive hypoxia<\/strong>:\r\n<ul>\r\n \t<li>Neurons require oxygen (survive 3-5 mins without it).<\/li>\r\n \t<li>Prolonged\u00a0<strong>ischemia<\/strong>\u00a0leads to\u00a0<strong>neuronal death<\/strong>.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Herniation syndromes<\/strong>:\r\n<ul>\r\n \t<li>Displacement of brain tissue within cranium and\/or through skull openings (e.g., foramen magnum).<\/li>\r\n \t<li><strong>Dangerous and often fatal<\/strong>.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<h1><strong>Brain Herniation Types and Effects<\/strong><\/h1>\r\n<strong>Types<\/strong>\r\n<ul>\r\n \t<li><strong>Supratentorial herniation<\/strong>:\r\n<ul>\r\n \t<li><strong>Downward<\/strong>\u00a0movement of brain tissue over the tentorial notch.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Uncal herniation<\/strong>:\r\n<ul>\r\n \t<li>Displacement of the\u00a0<strong>uncus<\/strong>\u00a0of the temporal lobe.<\/li>\r\n \t<li>Compresses\u00a0<strong>cranial nerve III<\/strong>\u00a0\u2192\u00a0<strong>fixed dilated pupil<\/strong>,\u00a0<strong>eye deviation<\/strong>.<\/li>\r\n \t<li>Can impair\u00a0<strong>RAS<\/strong>\u00a0\u2192 coma.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Tectal (midbrain) herniation<\/strong>:\r\n<ul>\r\n \t<li>Causes\u00a0<strong>altered consciousness<\/strong>\u00a0and\u00a0<strong>posturing<\/strong>.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Infratentorial herniation<\/strong>:\r\n<ul>\r\n \t<li><strong>Downward<\/strong>\u00a0herniation through the\u00a0<strong>foramen magnum<\/strong>.<\/li>\r\n \t<li>Compresses\u00a0<strong>brainstem<\/strong>, leading to\u00a0<strong>cardiovascular and respiratory arrest<\/strong>.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<strong>Effects<\/strong>\r\n<ul>\r\n \t<li>Compression of vital centers.<\/li>\r\n \t<li>Loss of\u00a0<strong>motor and sensory<\/strong>\u00a0function depending on herniation site.<\/li>\r\n \t<li><strong>Deep coma<\/strong>\u00a0and\u00a0<strong>death<\/strong>\u00a0if untreated.<\/li>\r\n<\/ul>\r\n<h1><strong>Signs and Symptoms of Elevated ICP<\/strong><\/h1>\r\n<strong>Key Signs<\/strong>\r\n<ul>\r\n \t<li><strong>Systemic hypertension<\/strong>:\r\n<ul>\r\n \t<li><strong>High systolic blood pressure<\/strong>.<\/li>\r\n \t<li><strong>Increased pulse pressure<\/strong>\u00a0(systolic \u2013 diastolic).<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Altered consciousness<\/strong>:\r\n<ul>\r\n \t<li>Progress from\u00a0<strong>lethargy<\/strong>\u00a0and\u00a0<strong>confusion<\/strong>\u00a0to\u00a0<strong>unresponsiveness<\/strong>.<\/li>\r\n \t<li><strong>Decreased responsiveness<\/strong>\u00a0often indicates worsening ICP.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<strong>Eye and Reflex Signs<\/strong>\r\n<ul>\r\n \t<li><strong>Dilated, fixed pupils<\/strong>\u00a0(blown pupils):\r\n<ul>\r\n \t<li>No response to light due to\u00a0<strong>cranial nerve III (oculomotor)<\/strong>\u00a0compression.<\/li>\r\n \t<li><strong>Unilateral<\/strong>\u00a0or\u00a0<strong>bilateral<\/strong>\u00a0dilation depending on lesion location.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Visual changes<\/strong>:\r\n<ul>\r\n \t<li>Swelling\u00a0<strong>optic disc<\/strong>\u00a0(papilledema).<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li><strong>Abnormal eye movements<\/strong>:\r\n<ul>\r\n \t<li><strong>Oculocephalic (Doll\u2019s eyes)<\/strong>\u00a0reflex: eyes move opposite to head movement if brainstem intact.<\/li>\r\n \t<li><strong>Oculovestibular<\/strong>\u00a0(caloric) reflex: eyes gaze toward cold water, away from warm.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<strong>Headache and Vomiting<\/strong>\r\n<ul>\r\n \t<li><strong>Severe headache<\/strong>\u00a0due to meningeal stretching.<\/li>\r\n \t<li><strong>Projectile vomiting<\/strong>\u00a0caused by pressure on\u00a0<strong>vomit<\/strong>\u00a0center in medulla.<\/li>\r\n<\/ul>\r\n<h1><strong>Diagnostic Methods for Elevated ICP<\/strong><\/h1>\r\n<strong>Imaging<\/strong>\r\n<ul>\r\n \t<li><strong>CT scans<\/strong>: Detect tumors, hemorrhages, swelling.<\/li>\r\n \t<li><strong>MRI<\/strong>: Detailed brain structure, edema, herniation.<\/li>\r\n \t<li><strong>Angiography<\/strong>: Visualize blood flow and vessel integrity.<\/li>\r\n \t<li><strong>Ultrasound<\/strong>: Transcranial, when feasible.<\/li>\r\n<\/ul>\r\n<strong>Lumbar Puncture<\/strong>\r\n<ul>\r\n \t<li>Measures\u00a0<strong>CSF pressure<\/strong>:\r\n<ul>\r\n \t<li><strong>Normal<\/strong>: &lt;20 mm Hg.<\/li>\r\n \t<li>Elevated\u00a0<strong>&gt;20 mm Hg<\/strong>\u00a0indicates increased ICP.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li>CSF analysis:\r\n<ul>\r\n \t<li><strong>Blood (hemorrhage)<\/strong>.<\/li>\r\n \t<li><strong>White blood cells<\/strong>\u00a0(infection).<\/li>\r\n \t<li><strong>Protein<\/strong>\u00a0(tumor, inflammation).<\/li>\r\n \t<li><strong>Color<\/strong>\u00a0(pink for hemorrhage).<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<strong>Additional Tests<\/strong>\r\n<ul>\r\n \t<li><strong>EEG<\/strong>: Brain activity monitoring.<\/li>\r\n \t<li><strong>Monitoring<\/strong>:\r\n<ul>\r\n \t<li>Frequent assessment of vital signs.<\/li>\r\n \t<li>Ophthalmic exam for\u00a0<strong>papilledema<\/strong>.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<h1><strong>Treatments<\/strong><\/h1>\r\n<ul>\r\n \t<li>Treatment Goals:\u00a0 Reduce <strong>ICP<\/strong>:\r\n<ul>\r\n \t<li><strong>Diuretics<\/strong>.<\/li>\r\n \t<li><strong>Steroids<\/strong>.<\/li>\r\n \t<li><strong>Surgical decompression<\/strong>\u00a0(craniectomy).<\/li>\r\n \t<li><strong>Drain CSF<\/strong>\u00a0via ventriculostomy if necessary.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<h1><strong>Summary<\/strong><\/h1>\r\n<ul>\r\n \t<li>ICP increases due to fluid buildup or bleeding; causes neuronal ischemia.<\/li>\r\n \t<li>The body\u2019s\u00a0<strong>compensation mechanisms<\/strong>\u00a0can become\u00a0<strong>self-perpetuating<\/strong>, worsening injury.<\/li>\r\n \t<li><strong>Cushing\u2019s reflex<\/strong>\u00a0signals a critical, life-threatening escalation.<\/li>\r\n \t<li>Care requires\u00a0<strong>prompt intervention<\/strong> to reduce ICP and restore blood flow.<\/li>\r\n \t<li>Imaging, CSF analysis, and clinical signs guide management.<\/li>\r\n \t<li>Rapid identification and treatment are vital.<\/li>\r\n<\/ul>","rendered":"<h1><strong>Causes of Increased ICP<\/strong><\/h1>\n<ul>\n<li><strong>Trauma<\/strong>,\u00a0<strong>tumors<\/strong>,\u00a0<strong>hemorrhage<\/strong>.<\/li>\n<li><strong>Inflammation<\/strong>\u00a0or\u00a0<strong>infection<\/strong>.<\/li>\n<li><strong>Obstruction of cerebrospinal fluid (CSF) drainage<\/strong>:\n<ul>\n<li>CSF is produced in the brain\u2019s ventricles and drains into the jugular vein.<\/li>\n<li>Blockage causes CSF accumulation, increasing volume and pressure.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h1><strong>Pathophysiology of ICP<\/strong><\/h1>\n<ul>\n<li><strong>Normal<\/strong>: Brain, blood, and CSF are within a\u00a0<strong>rigid skull<\/strong>.<\/li>\n<li><strong>Increase<\/strong>\u00a0in fluid (blood, CSF, edema) raises\u00a0<strong>pressure<\/strong>.<\/li>\n<li><strong>Brain tissues<\/strong>\u00a0are\u00a0<strong>pressure-sensitive<\/strong>\u00a0and can become ischemic if pressure cuts off blood flow.<\/li>\n<\/ul>\n<h1><strong>Body\u2019s Compensation for Increased ICP<\/strong><\/h1>\n<ul>\n<li><strong>Initial response<\/strong>:\n<ul>\n<li><strong>Shifting CSF<\/strong>\u00a0from ventricles into the spinal canal to reduce intracranial volume.<\/li>\n<li>Results in\u00a0<strong>ventricle shrinking<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Cerebrovascular Vasodilation<\/strong>:\n<ul>\n<li>Local\u00a0<strong>hypoxia<\/strong>\u00a0causes\u00a0<strong>nitric oxide<\/strong>\u00a0release, dilating vessels.<\/li>\n<li>Temporarily\u00a0<strong>increases blood flow<\/strong>\u00a0to brain to compensate.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Vasoconstriction<\/strong>:\n<ul>\n<li>Increased volume and pressure lead to <strong>pinching <\/strong>off of<strong> brain capillaries.<\/strong><\/li>\n<li>Reduced\u00a0<strong>cerebral blood flow<\/strong>, worsening\u00a0<strong>ischemia<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>Worsening Condition<\/strong><\/p>\n<ul>\n<li>Persistent ICP causes\u00a0<strong>capillary constriction<\/strong>, decreasing\u00a0<strong>oxygen supply<\/strong>.<\/li>\n<li>Brain becomes\u00a0<strong>hypoxic<\/strong>.<\/li>\n<li>The\u00a0<strong>medulla oblongata<\/strong>\u00a0triggers\u00a0<strong>Cushing\u2019s reflex<\/strong>.<\/li>\n<\/ul>\n<h1><strong>Cushing\u2019s Reflex (Triad)<\/strong><\/h1>\n<ul>\n<li><strong>Triggered<\/strong>\u00a0by brain ischemia.<\/li>\n<li><strong>Goal<\/strong>: Maintain blood flow to brain but often worsens ICP.<\/li>\n<\/ul>\n<p><strong>Cushing\u2019s Triad: Classic Signs of Increased ICP:<\/strong><\/p>\n<ol>\n<li><strong>Systemic hypertension<\/strong>:\n<ul>\n<li>Increased <strong>systolic blood pressure<\/strong>\u00a0(fight or flight response).<\/li>\n<\/ul>\n<\/li>\n<li><strong>Bradycardia<\/strong>:\n<ul>\n<li><strong>Slowed heart rate<\/strong>\u00a0(baroreceptor reflex in carotid arteries).<\/li>\n<\/ul>\n<\/li>\n<li><strong>Reduced respiration rate<\/strong>:\n<ul>\n<li>Hypoxia and low CO<sub>2<\/sub> levels reduce\u00a0<strong>respiratory drive<\/strong>.<\/li>\n<li>Leads to <strong>hypoventilation, hypoxia<\/strong>,\u00a0<strong>hypercapnia<\/strong>\u00a0exacerbates injury.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<p><strong>Pathophysiology of Cushing\u2019s Triad<\/strong><\/p>\n<ul>\n<li>Brain ischemia triggers\u00a0<strong>sympathetic activation<\/strong>\u00a0\u2192 vasoconstriction \u2192 high blood pressure.<\/li>\n<li>Baroreceptors detect high pressure \u2192\u00a0<strong>reflex bradycardia<\/strong>.<\/li>\n<li>Increased ICP reduces\u00a0<strong>CO\u2082<\/strong>\u00a0levels (<strong>hypocapnia<\/strong>) \u2192\u00a0<strong>respiratory depression<\/strong>.<\/li>\n<\/ul>\n<h1><strong>Outcomes and Risks<\/strong><\/h1>\n<ul>\n<li><strong>Temporary<\/strong>\u00a0increase in blood flow\u00a0<strong>relieves<\/strong>\u00a0ischemia briefly.<\/li>\n<li><strong>Vicious cycle<\/strong>:\n<ul>\n<li>Increased pressure \u2192 more ischemia \u2192 further brain damage.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Progression<\/strong>:\n<ul>\n<li>Decreased neuronal function.<\/li>\n<li>Unresponsive coma.<\/li>\n<li>Potential\u00a0<strong>brain death<\/strong>\u00a0if ICP persists.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>Consequences of Unmanaged ICP<\/strong><\/p>\n<ul>\n<li><strong>Progressive hypoxia<\/strong>:\n<ul>\n<li>Neurons require oxygen (survive 3-5 mins without it).<\/li>\n<li>Prolonged\u00a0<strong>ischemia<\/strong>\u00a0leads to\u00a0<strong>neuronal death<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Herniation syndromes<\/strong>:\n<ul>\n<li>Displacement of brain tissue within cranium and\/or through skull openings (e.g., foramen magnum).<\/li>\n<li><strong>Dangerous and often fatal<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h1><strong>Brain Herniation Types and Effects<\/strong><\/h1>\n<p><strong>Types<\/strong><\/p>\n<ul>\n<li><strong>Supratentorial herniation<\/strong>:\n<ul>\n<li><strong>Downward<\/strong>\u00a0movement of brain tissue over the tentorial notch.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Uncal herniation<\/strong>:\n<ul>\n<li>Displacement of the\u00a0<strong>uncus<\/strong>\u00a0of the temporal lobe.<\/li>\n<li>Compresses\u00a0<strong>cranial nerve III<\/strong>\u00a0\u2192\u00a0<strong>fixed dilated pupil<\/strong>,\u00a0<strong>eye deviation<\/strong>.<\/li>\n<li>Can impair\u00a0<strong>RAS<\/strong>\u00a0\u2192 coma.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Tectal (midbrain) herniation<\/strong>:\n<ul>\n<li>Causes\u00a0<strong>altered consciousness<\/strong>\u00a0and\u00a0<strong>posturing<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Infratentorial herniation<\/strong>:\n<ul>\n<li><strong>Downward<\/strong>\u00a0herniation through the\u00a0<strong>foramen magnum<\/strong>.<\/li>\n<li>Compresses\u00a0<strong>brainstem<\/strong>, leading to\u00a0<strong>cardiovascular and respiratory arrest<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>Effects<\/strong><\/p>\n<ul>\n<li>Compression of vital centers.<\/li>\n<li>Loss of\u00a0<strong>motor and sensory<\/strong>\u00a0function depending on herniation site.<\/li>\n<li><strong>Deep coma<\/strong>\u00a0and\u00a0<strong>death<\/strong>\u00a0if untreated.<\/li>\n<\/ul>\n<h1><strong>Signs and Symptoms of Elevated ICP<\/strong><\/h1>\n<p><strong>Key Signs<\/strong><\/p>\n<ul>\n<li><strong>Systemic hypertension<\/strong>:\n<ul>\n<li><strong>High systolic blood pressure<\/strong>.<\/li>\n<li><strong>Increased pulse pressure<\/strong>\u00a0(systolic \u2013 diastolic).<\/li>\n<\/ul>\n<\/li>\n<li><strong>Altered consciousness<\/strong>:\n<ul>\n<li>Progress from\u00a0<strong>lethargy<\/strong>\u00a0and\u00a0<strong>confusion<\/strong>\u00a0to\u00a0<strong>unresponsiveness<\/strong>.<\/li>\n<li><strong>Decreased responsiveness<\/strong>\u00a0often indicates worsening ICP.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>Eye and Reflex Signs<\/strong><\/p>\n<ul>\n<li><strong>Dilated, fixed pupils<\/strong>\u00a0(blown pupils):\n<ul>\n<li>No response to light due to\u00a0<strong>cranial nerve III (oculomotor)<\/strong>\u00a0compression.<\/li>\n<li><strong>Unilateral<\/strong>\u00a0or\u00a0<strong>bilateral<\/strong>\u00a0dilation depending on lesion location.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Visual changes<\/strong>:\n<ul>\n<li>Swelling\u00a0<strong>optic disc<\/strong>\u00a0(papilledema).<\/li>\n<\/ul>\n<\/li>\n<li><strong>Abnormal eye movements<\/strong>:\n<ul>\n<li><strong>Oculocephalic (Doll\u2019s eyes)<\/strong>\u00a0reflex: eyes move opposite to head movement if brainstem intact.<\/li>\n<li><strong>Oculovestibular<\/strong>\u00a0(caloric) reflex: eyes gaze toward cold water, away from warm.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>Headache and Vomiting<\/strong><\/p>\n<ul>\n<li><strong>Severe headache<\/strong>\u00a0due to meningeal stretching.<\/li>\n<li><strong>Projectile vomiting<\/strong>\u00a0caused by pressure on\u00a0<strong>vomit<\/strong>\u00a0center in medulla.<\/li>\n<\/ul>\n<h1><strong>Diagnostic Methods for Elevated ICP<\/strong><\/h1>\n<p><strong>Imaging<\/strong><\/p>\n<ul>\n<li><strong>CT scans<\/strong>: Detect tumors, hemorrhages, swelling.<\/li>\n<li><strong>MRI<\/strong>: Detailed brain structure, edema, herniation.<\/li>\n<li><strong>Angiography<\/strong>: Visualize blood flow and vessel integrity.<\/li>\n<li><strong>Ultrasound<\/strong>: Transcranial, when feasible.<\/li>\n<\/ul>\n<p><strong>Lumbar Puncture<\/strong><\/p>\n<ul>\n<li>Measures\u00a0<strong>CSF pressure<\/strong>:\n<ul>\n<li><strong>Normal<\/strong>: &lt;20 mm Hg.<\/li>\n<li>Elevated\u00a0<strong>&gt;20 mm Hg<\/strong>\u00a0indicates increased ICP.<\/li>\n<\/ul>\n<\/li>\n<li>CSF analysis:\n<ul>\n<li><strong>Blood (hemorrhage)<\/strong>.<\/li>\n<li><strong>White blood cells<\/strong>\u00a0(infection).<\/li>\n<li><strong>Protein<\/strong>\u00a0(tumor, inflammation).<\/li>\n<li><strong>Color<\/strong>\u00a0(pink for hemorrhage).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>Additional Tests<\/strong><\/p>\n<ul>\n<li><strong>EEG<\/strong>: Brain activity monitoring.<\/li>\n<li><strong>Monitoring<\/strong>:\n<ul>\n<li>Frequent assessment of vital signs.<\/li>\n<li>Ophthalmic exam for\u00a0<strong>papilledema<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h1><strong>Treatments<\/strong><\/h1>\n<ul>\n<li>Treatment Goals:\u00a0 Reduce <strong>ICP<\/strong>:\n<ul>\n<li><strong>Diuretics<\/strong>.<\/li>\n<li><strong>Steroids<\/strong>.<\/li>\n<li><strong>Surgical decompression<\/strong>\u00a0(craniectomy).<\/li>\n<li><strong>Drain CSF<\/strong>\u00a0via ventriculostomy if necessary.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h1><strong>Summary<\/strong><\/h1>\n<ul>\n<li>ICP increases due to fluid buildup or bleeding; causes neuronal ischemia.<\/li>\n<li>The body\u2019s\u00a0<strong>compensation mechanisms<\/strong>\u00a0can become\u00a0<strong>self-perpetuating<\/strong>, worsening injury.<\/li>\n<li><strong>Cushing\u2019s reflex<\/strong>\u00a0signals a critical, life-threatening escalation.<\/li>\n<li>Care requires\u00a0<strong>prompt intervention<\/strong> to reduce ICP and restore blood flow.<\/li>\n<li>Imaging, CSF analysis, and clinical signs guide management.<\/li>\n<li>Rapid identification and treatment are vital.<\/li>\n<\/ul>\n","protected":false},"author":1370,"menu_order":18,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["zoe-soon"],"pb_section_license":"cc-by-nc-sa"},"chapter-type":[],"contributor":[60],"license":[57],"class_list":["post-5471","chapter","type-chapter","status-web-only","hentry","contributor-zoe-soon","license-cc-by-nc-sa"],"part":76,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters\/5471","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/users\/1370"}],"version-history":[{"count":9,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters\/5471\/revisions"}],"predecessor-version":[{"id":5480,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters\/5471\/revisions\/5480"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/parts\/76"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapters\/5471\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/media?parent=5471"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/pressbooks\/v2\/chapter-type?post=5471"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/contributor?post=5471"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/wp-json\/wp\/v2\/license?post=5471"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}