Module 13 (Patho 2).docx

Increased Intracranial Pressures Lecture Guide Brain: _2_% of body weight Receives 1/6 of cardiac output Consumes _20_% of oxygen Hypoxia: Blood flow is adequate but pO2 is low: hypoxic hypoxia (not enough oxygen in the blood) H/H is low: anemic hypoxia (Hemoglobin and hematocrit are low due to not...

Increased Intracranial Pressures Lecture Guide Brain: _2_% of body weight Receives 1/6 of cardiac output Consumes _20_% of oxygen Hypoxia: Blood flow is adequate but pO2 is low: hypoxic hypoxia (not enough oxygen in the blood) H/H is low: anemic hypoxia (Hemoglobin and hematocrit are low due to not enough cells to carry oxygen to the brain). Chronic hypoxia: is well tolerated. When pO2 drops the brain learns to extract more oxygen from the hemoglobin that passes by. Chronic pulmonary disease [COPD and emphysema] Sudden hypoxia: Anoxia not tolerated Coma is possible Cortical damage often is irreversible Ex: Respiratory arrest Ischemia Defined as an inadequate arterial blood supply: reduced _Blood_ and _ocygen__ flow. Resulting in __Reduced__ oxygen and glucose to brain __Removal__ of waste products is impaired Etiologies: Cardiac: cardiac arrest Vascular: atherosclerosis that reduces oxygenated blood flow to the brain = ischemic. Global blood flow inadequate to meet metabolic demands Cardiac arrest - decrease cardiac output to the rest of the brain. Focal – local thrombus: __CVA or Ischemic Brain Attack__ emboli: ____A-Vif. or ischemic ____ Brain without oxygen: begin to die in __4-6___minutes, irreversible loss by _10__ minutes Basic Concept “Trigger” Increase in volume 🡪 pressure in cranium Increased IntraCranial Pressure: Compartment Syndrome Ischemic Tissue Changes in LOC, abnormal movement, respiratory and cardiovascular patterns Increased Intracranial Pressure (IICP) Intracranial Compartment Syndrome Problem:_Increased_ volume in a container that can’t __stretch__ 🡪 increased __pressure___ Cranium cannot _stretch_ to accommodate an increase in __volume_ Compartments in cranium Brain = _80%__of volume Blood = _10%_ of volume CSF = __10%__of volume Monroe-Kellie Hypothesis: a change in volume of one compartment must be offset by a change in the volume of other compartments normal cranial cavity pressures maintained by controlling volume of blood & CSF If inflammatory fluid, bleeding or tumor increases the volume in the cranial cavity, the _pressure_ within the cranium may increase → compression of _arterial blood_ supply 🡪 _would lead to ischemia_. To maintain normal pressure within the brain the volume of _blood_ or _cerebrospinal_ tries to decrease. Want no more than 100% volume in cranium If volume of brain increases to 82%, then _cerebrospinal fluid_ or __blood flow_ has to drop in order to maintain volume at 100% CSF volume _decrease_ _decrease_ formation _Increased_ absorption into the _subarachnoid_ space Compress venous sinuses 🡪 push blood out of the brain Increasing volume over 100% can _increased_ pressure within the cranium → _decrease_ blood and oxygen supply and put brain tissues at risk. Ischemia → prolonged ischemia →cell death. Cerebral compensation to maintain perfusion and oxygenation Arteries dilate when the arterial BP is __low__...and constrict when the arterial BP is __High___. Less arterial blood flow → _Increased_ amounts of oxygen “pulled” from Hgb Summary: When volume in the cranium rises pressure often _Increased_.....increase volume → _Increased_ intracranial pressure → risk for _ischemia___ What’s the “compartment” or “container”? bony cranium. What could increase the volume in the container? Hemorrhage into the tissues and any type of inflammatory fluid, tumors, and anything that increases the volume of tumor in the cranial cavity can increase the pressure and result in ischemia. Etiologies/Triggers of IICP: Tumor: tumor could obstruct venous return or CSF circulation → further _Increased_ volume and pressure Blood/Hematoma Inflammation: Inflammation …fluid moves from capillaries into brain tissue → _Increased_volume → _Increased_pressure Injured tissues cerebral ischemia thrombus embolus traumatic brain injury [TBI] Increased CSF volume in Cranial nerve R/T: decreased reabsorption meningitis subarachnoid hemorrhage obstruction: tumors, brain swelling Hyponatremia as etiology for IICP …by shifting fluid into the brain 🡪 increased brain volume hyponatremia → particles within the cell greater than particles outside the cell → particles in cell exert a “pull” → fluid shifts _into_ cell → cell __swells and increases volume within the cranium__ → compressing blood vessels and oxygen supply Why would a sodium free IV solution result in increased intracranial pressure sodium free solution → dilute _serum sodium__ 🡪 _hypo_natremia……..fluid shifts _into_ cells 🡪 brain swells and compresses blood supply. Review IICP: Similarities - __Increased__ volume and ___pressure___ in cranial cavity _Increased_ volume in cranial cavity → _Increased_ pressure Pressure _Increases _ because cranial cavity cannot stretch to accommodate the _Increased_ volume IICP compresses blood vessels → _decrease_ arterial blood flow IICP → _decrease_ oxygen delivery to tissues of the brain IICP → tissue _ischemic_ and later tissue _nercosis_ Result → pressure on cortex → anoxia → _Cortical_ death (unresponsive wakefulness syndrome) → pressure on brain stem → _Brain_ death Normal Intracranial Pressure: _7-15_mmHg Loss of compensation at _20-25_mmHg - results ischemic s/s S/S of IICP: Related to cerebral ischemia Change in Level of Consciousness Match LOC with definition (Table 16-2) Confusion Unarousable, unresponsive to external stimuli Delirium Not unconscious but little or no spontaneous activity Obtundation Decreased alertness with psychomotor retardation Stupor Impaired ability to think clearly, perceive, respond or remember Coma Motor restlessness, hallucination, delirium Papilledema = __Increased__ pressure of CSF against __optic___ nerve Due to __Increased__CSF reabsorbed into subarachnoid space In IICP is related to increased volume of CSF in the subarachnoid space → increased __volume__ of CSF in the subarachnoid → pressure on optic nerve Bulging optic disc Transient visual changes: Retinal ischemia dim vision, blurring Cushing Reflex or Triad Adaptive: try to increase blood flow to brain by: increasing systolic BP Increase pulse pressure bradycardia abnormal respiratory patterns Review: A person with suspected IICP is noted to have a BP that increased from 130/80 to 180/90 and a heart rate that dropped from 68 to 50. True or False: These findings make the definitive diagnosis of IICP. False The respiratory pattern may be irregular. True This person is experiencing brain death. False Review: A person with suspected IICP is noted to have a BP that increased from 130/80 to 180/90 and a heart rate that dropped from 68 to 50. The bradycardia occurs because the body is trying to compensate for the rising __blood pressure__. Lowering the HR will _lower_ the cardiac output and _lower_ the blood pressure. (BP = CO X total peripheral resistance.) The SNS does not know the BP is rising in an attempt to overcome _resistance_ in the brain, in an attempt to increase _blood_ flow to the tissues and reverse cerebral ischemia. A person with suspected IICP is noted to have a BP that increased from 130/80 to 180/90. The rise in BP is in an attempt to a. overcome the resistance/pressure in the brain b. improve cerebral perfusion c. reverse the ischemia d. all of the above Monitoring for IICP Definitive Diagnosis: Invasive monitoring Treatment for IICP …“compartment syndrome of the brain” _increased_the volume in the container …or make the container __bigger__ Principle: _decrease_ volume in a container → _decrease_ pressure …or increase size of container → _decrease_ pressure Myofascial compartment syndrome is to orthopedic conditions as _increase intracranial pressure_ is to the brain. Which of the following are ISCHEMIC pathos, are etiologies for acute arterial occlusion? Check all that apply. ✅ orthopedic compartment syndrome ✅ plaque rupture in atherosclerosis ✅ IICP Goal:__Re-perfusion___ Problem: __Ischemia___ Reduce or Relieve the Ischemia Decrease volume in cranium → decrease pressure → decompress the blood supply → increased oxygen and nutrient flow into the brain and allow carbon dioxide and waste products to leave the brain Treatment Options: Drain off CSF Decrease volume → decrease pressure → increased oxygen flow to cerebral tissues Removal of volume Remove tumor mass or clot Decrease volume → decrease pressure → increased oxygen flow to tissues Chemical therapy to decrease volume Diuretics ... may reduce formation of CSF. Steroids.. anti-inflammatory Mannitol (hyperosmolar agents) - When the particles of the blood pull water from cells. Control respiratory rate and depth Increase in TV and/or Rate → maintain oxygen concentration in blood and maintain normal pCO2 Review: Treatment to reduce IICP includes reducing the volume of the brain. Which of the following interventions does not result in reducing the volume in the brain? a. cortisol like drugs b. Mannitol ® c. removal of bone flap: craniectomy d. drain CSF Treatment to reduce IICP includes increasing the size of the cranial “container”. Which of the following interventions results in increasing the size of the cranial “container”? a. cortisol like drugs b. Mannitol® c. removal of bone flap: craniectomy d. drain CSF Craniectomy Make container __bigger_ Complications of IICP: coma and herniation Glasgow coma scale: determine degree of coma S/S: related to global brain injury Diminished LOC Altered respiratory response Change in rate or pattern Decorticate posturing: “damage to the corticospinal tract pathway between brain spinal cord.” Decerebrate posturing: “A severe injury to the brain near or at the level of brainstem.” Doll’s Eyes Brain herniation – terminal complication of IICP Cushing Reflex: Increase systolic BP, abnormal respiratory pattern, bradycardia Very low coma scale IICP Related concern: Brain Death …the absence of clinical brain function when the cause is identified and irreversible “…irreversible loss of function of the brain, including the brainstem. According to Ohio law, patients who meet the criteria for brain death are dead.” Recognizes mandatory criteria for diagnosing brain death in the adult. Fixed and dilated pupils No motor response No corneal response No gag reflex No cough response No response to pain No respirations Apnea test Confirmatory test but Not mandatory EEG Cerebral blood flow studies Transcranial ultrasonography Cerebral angiography Spinal cord reflex – Lazarus sign Review: Brain death means the a. person is legally dead b. heart has stopped beating c. cortex is lost but the brainstem is intact d. person is in a coma Review: A beating heart organ donor a. is legally dead b. exists in a vegetative state c. has an intact brainstem d. has an ischemic cortex IICP is a compartment syndrome… _Increased_ volume in a container that cannot stretch → _Increased_ pressure The brain is pushing down towards the _foramen_ _magnum__ risking brain death related to pressure on the _brainstem_ What do cortisol-like drugs, Mannitol and draining off CSF have in common? infusion of particles suppression of inflammatory fluid requires use of intraventricular catheter decreasing intracranial volume Cortisol-like drugs, Mannitol ® and draining off CSF: Arrange the steps in order: decreasing intracranial volume 🡪 reversing ischemia. _1_ decrease intracranial volume _4_ re-oxygenate the brain _2_ decrease pressure _3_ decompress cerebral arteries _5_ reverse cerebral ischemia _6_ save the tissues IICP related concern: Unresponsive Wakefulness Syndrome “…loss of all cognitive functions and unawareness of self and surroundings.” Cerebral atrophy Diagnosis: s/s lasts longer than 1 month Normal Sleep-Wake Cycles Bowel and bladder incontinence No reproducible voluntary actions No Response to Environmental Stimuli … no visual tracking, lack of language comprehension Diffuse Brain Injury with Preservation of Brain Stem Function Etiologies for unresponsive wakefulness syndrome: IICP Cardiac arrest Respiratory arrest Review: Unresponsive Wakefulness Syndrome means [Check all that apply.] ____ the person is legally dead ____ brain herniation has occurred _✔_ “cortical failure” has occurred, brainstem is intact Summary Brain Death: Not Awake…Not Aware Unresponsive Wakefulness Syndrome: Awake but Unaware Traumatic Brain Injury (Head Injury).. etiology for IICP Most common trigger: __Falls__ Coup contrecoup injury: Head moves forward and back inside cranial cavity. Concussion: S/S: short or long term Brain elongation Rotational injury: Twisted, stretch, and tearing Cognitive problems Learning Memory retrieval Putting it all together. Arrange the steps in order: Concussion. _4_ axons stretched or twisted _1_ something “crashes” into the skull _2_ brain moves within the skull _3_ brain elongates Review: Which of the following has to be true about concussion? a. it is just a bump on the head b. cognitive and behavioral symptoms are present c. the brain bounces around in the skull d. CT or MRI is needed to make the diagnosis Review: Which of the following is true about a mild concussion? a. a well-fitting helmet will prevent concussion b. most recover in about 7 days c. a coach can determine when an athlete is fit to return to the field d. a person can feel the severity of a concussion Contusion: cerebral bruise Evidence on MRI or CT scan ⇨ Chronic Traumatic Encephalopathy (CTE) brain degeneration likely caused by repeated head traumas definitive diagnosis only made at autopsy most common in: Occurs mostly in contact sports (football) and battlefield (Soldiers) but it's usually rare in the general public. S/S: difficulties with thinking (cognition), physical problems, emotions and other behaviors. Hematomas.. etiology for IICP hematomas occupy space → _Increased_ volume and _Increased_ pressure within cranial cavity Types of Hematomas Subdural Hematoma: Tear __venous__ veins with blood collecting between dura & brain. Case study: history of fall several weeks ago on ice – hit left side of head Reports weakness in right arm and leg Diagnosis: Epidural Hematoma Treatment: goal - requires the pressure in the brain to be decreased. _Increased_ volume → _Increased_ pressure → re-perfuse anti-inflammatory medications Burr Holes when possible, herniation is suspected – craniectomy A person with cerebral ischemia may be at risk for seizures and anticonvulsants should be given, if needed. remove the clot Epidural Hematoma: Middle meningeal artery S/S: rapid onset Treatment: Surgery to remove the clot Relieve pressure Reduce IICP Improve Cerebral Perfusion Pressure Review: What do SDH, epidural hematoma and concussion have in common? a. traumatic brain injury is an etiology b. bleeding c. stretching of the brain and axons d. rapid onset of signs and symptoms Concussion, contusion, brain surgery for hematomas can result in diabetes insipidus What is DI? Deficient antidiuretic hormone. What causes DI? Trauma to hypothalamus. How would it show up? Polyuria Treatment? Vasopressin and replace lost fluids until DI resolves itself. Cerebral Aneurysms .. etiology for IICP Subarachnoid Hemorrhage (SAH) ~ Increased volume in the cranium and increased the pressure. Intracerebral Hemorrhage 🡪 hemorrhagic brain attack Aneurysm definition: An abnormal local dilatation in the wall of a blood vessel, usually an artery. Etiologies: Congenital Hypertension - Weakening of arterial wall. Atherosclerosis and shearing injury. unknown S/S - Early: based on cerebral tissue being compressed Subarachnoid hemorrhage when aneurysm ruptures S/S: Worst headache - R/T leaks prior rupture Nausea/vomiting Photophobia Diagnosis CT Scan Lumbar puncture: Treatment Reduce IICP Prevent vasospasm Prevent seizure Stop bleed: Prevention aneurysm from rupturing BP __Quit__ smoking Fill aneurysm with __Coils__ Surgical clipping Review: A person is diagnosed with a cerebral aneurysm. What has to be true about the cerebral aneurysm? a. aneurysm was found deep within the brain b. aneurysm was found in the Circle of Willis c. aneurysm was the result of artery muscle weakness d. aneurysm will result in hemorrhagic brain attack Arrange the steps in order: SAH. (Subarachnoid hemorrhage) _4_ IICP and ischemia _5_ changes in LOC _1_ rupture of middle cerebral artery aneurysm _2_ bleeding into the subarachnoid space _3_ headache, stiff neck, photophobia Intracranial aneurysms – most common problem treated to prevent hemorrhagic stroke Meningitis.. etiology for IICP Etiologies Haemophilus influenzae: Hib vaccine First dose at 2 months Pneumococcal meningitis:   pneumococcal conjugate  Start series at 2 months  Neisseria meningitidis meningococcal meningitis: vaccine for older children The first dose should be given at 11-12 years old and a booster dose at 16 years old. CLASS ACT Analysis Fever, chills - Caused by infection. N/V - Impact of the medulla. Photophobia - Due to optic nerve passing through subarachnoid space, then passes through the meninges and when meninges are irritated that influences the optic nerve (light sensitive). Mental status changes - Related to increased intracranial pressure (ischemia). Physical Kernig’s Sign - When the leg is raised. Brudzinksi’s Neck sign - When the neck is flexed. Definitive diagnostic test: Gram stain, glucose, and pathogens. CSF tap/lumbar puncture (between L3 and L4) Diagnosis - CT Scan: dilated lateral ventricles would be related to obstruction of _Cerebral spinal_ flow. Meninges swollen 🡪 subarachnoid space is _swollen_ _shut_. Arrange the steps in order: meningitis to hydrocephalus _1_ exposure to Haemophilus influenzae _2_ meninges are inflamed [meningitis] _3_ meninges become swollen _6_ hydrocephalus on x-ray _4_ less CSF enters the subarachnoid space _5_ CSF backs up into the lateral ventricles Hydrocephalus can be related to: Meningitis __Tumor____ __Bleeding__ __TBI [Traumatic Brain Injury]__ Prevention Vaccination - Infants - pneumococcal meningitis. Adults living in close quarters: meningococcal meningitis vaccine. Treatment Antibiotics – bacterial meningitis Drugs that Reduce brain swelling like steroids Other symptomatic treatments such as headache, a darkened room for photophobia, and etc. Fill in the Blanks: Meningococcal Meningitis Most can live with the bacteria in the airway and not become infected. In some cases the _immune_ system is not able to fight against the bacteria. Meningococcal meningitis ( _bacterial_ meningitis) → inflammation of __meninges__, the covering of the brain. Inflammation → _increases_ fluid accumulation around the brain 🡪 _increases_ pressure within the cranial cavity ( _increased__ intracranial pressure or IICP) Incubation period: _2_ to _10_ days. average = 4 days N/V, aches and pains, restlessness Meningeal signs include stiff _neck_ ( nuchal _rigidity_) and sensitivity to light (_photophobia_), headache Inflammatory signs include: _elevated_ temperature and _increased_ WBC. meningococcal septicemia 🡪 Septic Shock Shock defined as catastrophic decrease in _cardiac output_ (cardiogenic shock) or _casatrophic decrease__ (circulatory shock) → BP insufficient to perfuse and maintain life of cells, tissues and organs Septic shock means toxins in blood → vaso_dilation__ → etiology of reduction in BP and CO Toxins enter blood → damages blood vessels → __results in bleeding, bruising, and rash (bleeding into microcirculation and into subcutaneous tissues.__ Sluggish blood – clots, impaired fibrinolysis, low anticoagulants Toxins enter blood → fluid moves from capillaries into surrounding tissue → BP drops, systemic perfusion drops → person goes into shock difficult to treat Toxins → vasodilate → _lowers BP perfusion_ Toxins → myocardial cell death → _Decrease_ cardiac output → decreases BP and shock state Some exhibit vasospasm → cold extremities, ischemia, necrosis High fatality rate with meningococcal septicemia → septic shock Review: A person with meningococcal septic shock has an elevated creatinine. What is happening to this person? Check all that apply. _✔_ low BP ____ potassium levels are falling → rising _✔_ reduced glomerular filtration rate ____ metabolic alkalosis → acidosis Encephalitis.. etiology for IICP Virus → inflammatory response One element of the inflammatory response = capillary dilation fluid movement into tissue → increase volume of fluid in the brain “triggers” increase in intracranial pressure Presenting S/S: related to ischemic tissue…IICP → compress blood and oxygen flow → changes in LOC MRI: Encephalitis R/T → Herpes simplex virus Treatment: Viral - antiviral medication Antibiotics if bacterial Sedatives for restlessness Tylenol for headache and fever Anti-seizure medication, if needed Anti-inflammatory medication may be needed Neoplasm..etiology for IICP S/S: Depends on area Person might present with seizures because: local pressure and ischemic → alter cell membrane → rapid and uncontrolled depolarization. Person might present with S/S of IICP because: Space occupying tumor, inflammation from damaged tissue → edema and pressure. S/S of IICP include: Changes in LOC - early signs…this is a hypoxic sign caused by pressure on blood vessels supplying the cortex. What does brain cancer have in common with all other cancers? Carcinogen initiates cellular changes … progresses from mild, moderate, severe dysplasia (carcinoma in situ) → metastasis … growth promoted by loss adhesion … uncontrolled cell growth … can be staged, graded…definitive diagnosis = biopsy. This cancer is determined to be astrocytoma which means: Aries from a particular type of neuroglial cell - the astrocyte )a glial cancer). Cancer cannot arise from the brain itself because: Cancer only arises from cells capable of dividing. Brain cancers are difficult to remove because: Malignancies are invasives, not encapsulated… and damage to surrounding brain tissue can be devastating. External radiation can be effective in relieving symptoms and improving longevity. Radiation is effective because: Radiation damages DNA → Inhibits cell division - especially the DNA of rapidly dividing cells … and cancer is rapidly dividing. Review Puzzle: Unscramble each of the clue words. Discover etiologies for IICP muosrt Tumor ghmahrereo Hemorrhage DSH SDH (subdural hematoma) dauperli edbel epidural bleed milmanfotnai Inflammation neimintigs meningitis myrnuase aneurysm ceiesadrn emvluo increased volume nrdaseiec sueurspe increased pressure Etiologies …the “triggers” that → IICP → decrease cerebral perfusion pressure [CPP] 🡪 ischemia → neuro S/S Name three disorders of the brain that can result in increased intracranial pressure. Inflammatory conditions: meningitis, encephalitis, tissue injury related to concussion, space occupying conditions such as tumors, failure of CSF to circulate is another issue (a complication of meningitis or pressure on drainage ducts from tumor). Explain why these conditions result in IICP. Inflammation →capillary permeability → fluid shift to interstitial tissues → brain swells but cranium cannot “give” → pressure is directed inward on the brain. Other issues: space occupying … tumors, increased volume of CSF … increased volume → increased in pressure. IICP, regardless of etiology, can present with similar S/S. Name these S/S. CHANGES IN LOC IICP → Compression of arterial blood going into the brain and compression of venous blood and CSF as it tries to leave the brain. Compression of arterial blood supply → ischemic changes in tissues → changes in LOC.