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Head Trauma. Introduction to Head Injuries. Common major trauma 4 million people experience head trauma annually Severe head injury is most frequent cause of trauma death GSW to cranium: 75-80% mortality At Risk population Males 15-24 Infants Young Children Elderly.
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Introduction to HeadInjuries • Common major trauma • 4 million people experience head trauma annually • Severe head injury is most frequent cause of trauma death • GSW to cranium: 75-80% mortality • At Risk population • Males 15-24 • Infants • Young Children • Elderly
Introduction to Head Injuries • TIME IS CRITICAL • Intracranial Hemorrhage • Progressing Edema • Increased ICP • Cerebral Hypoxia • Permanent Damage • Severity is difficult to recognize • Subtle signs • Improve differential diagnosis • Improves survivability
Pathophysiology ofHead Injury • Mechanism of Injury • Blunt Injury • Motor vehicle collisions • Assaults • Falls • Penetrating Injury • Gunshot wounds • Stabbing • Explosions
Different Types of Injury • Head Injury • Cranial Injury • Brain Injury
Head Trauma Open Skull compromised and brain exposed Closed Skull not compromised and brain not exposed Head Trauma - 6
Scalp Injury • Contusions • Lacerations • Avulsions • Significant Hemorrhage ALWAYS Reconsider MOI for severe underlying problems
Head Injuries Scalp wound Highly vascular, bleeds briskly Shock: child may develop Shock: adult another cause Management No unstable fracture: direct pressure, dressings Unstable fracture: dressings, avoid direct pressure Head Trauma - 8
Skull fracture Linear nondisplaced Depressed Compound Suspect fracture Large contusion or darkened swelling Management Dressing, avoid excess pressure Head Injuries Head Trauma - 9
Cranial Injury • Trauma must be extreme to fracture • Linear • Depressed • Open • Impaled Object
Basal Skull • Unprotected • Spaces weakenstructure • Relatively easier to fracture
Cranial Injury • Basal Skull Fracture Signs • Battle’s Signs • Retroauricular Ecchymosis • Associated with fracture of auditory canal and lower areas of skull • Raccoon Eyes • Bilateral Periorbital Ecchymosis • Associated with orbital fractures
Basilar Skull Fracture Battle’s sign Raccoon eyes Head Trauma - 13
Cranial Injury • Basilar Skull Fracture • May tear dura • Permit CSF to drain through an external passageway • May mediate rise of ICP • Evaluate for “Target” or “Halo” sign
Crainial Injuries Penetrating trauma Bullet fragments Head Trauma - 15
Forces that cause skull fracture can also cause brain injury. Head Trauma - 16
Brain Injury • As defined by the National Head Injury Foundation • “a traumatic insult to the brain capable of producing physical, intellectual, emotional, social and vocational changes.”
Brain Injury Response to injury Swelling of brain Vasodilatation with increased blood volume Increased ICP Decreased blood flow to brain Perfusion decreases Cerebral ischemia (hypoxia) Head Trauma - 18
Signs & Symptoms of Brain Injury • Altered Mental Status • Altered orientation • Alteration in personality • Amnesia • Retrograde • Antegrade • Cushing’s Reflex • Increased BP • Bradycardia • Erratic respirations • Vomiting • Without nausea • Projectile • Body temperature changes • Changes in pupil reactivity • Decorticate posturing
Signs & Symptoms of Brain Injury • Pathophysiology of Changes • Frontal Lobe Injury • Alterations in personality • Occipital Lobe Injury • Visual disturbances • Cortical Disruption • Reduce mental status or Amnesia • Retrograde • Unable to recall events before injury • Antegrade • Unable to recall events after trauma • “Repetitive Questioning” • Focal Deficits • Hemiplegia, Weakness or Seizures
Classification • Direct • Primary injury caused by forces of trauma • Indirect • Secondary injury caused by factors resulting from the primary injury
Brain Injury Direct brain injury Immediate damage due to force Coup and contracoup Fixed at time of injury Management Directed at prevention Head Trauma - 22
Direct Brain Injury Types • Coup • Injury at site of impact • Contrecoup • Injury on opposite side from impact
Brain Injury Indirect brain injury Results from hypoxia or decreased perfusion Response to primary injury Develops over hours Management Good prehospital care can help prevent Head Trauma - 24
Direct Brain Injury Categories • Focal • Occur at a specific location in brain • Differentials • Cerebral Contusion • Intracranial Hemorrhage • Epidural hematoma • Subdural hematoma • Intracerebral Hemorrhage • Diffuse • Concussion • Moderate Diffuse Axonal Injury • Severe Diffuse Axonal Injury
Focal Brain Injury • Cerebral Contusion • Blunt trauma to local brain tissue • Capillary bleeding into brain tissue • Common with blunt head trauma • Confusion • Neurologic deficit • Personality changes • Vision changes • Speech changes • Results from • Coup-contrecoup injury
Brain Injuries Cerebral contusion Bruising of brain tissue Swelling may be rapid and severe Level of consciousness Prolonged unconsciousness, profound confusion or amnesia Associated symptoms Focal neurological signs May have personality changes Head Trauma - 27
Focal Brain InjuryIntracranial Hemorrhage • Epidural Hematoma • Bleeding between dura mater and skull • Involves arteries • Middle meningeal artery most common • Rapid bleeding & reduction of oxygen to tissues • Herniates brain toward foramen magnum
Intracranial Hemorrhage Acute epidural hematoma Arterial bleed Temporal fracture common Onset: minutes to hours Level of consciousness Initial loss of consciousness “Lucid interval” follows Associated symptoms Ipsilateral dilated fixed pupil, signs of increasing ICP, unconsciousness, contralateral paralysis, death Head Trauma - 29
Focal Brain InjuryIntracranial Hemorrhage • Subdural Hematoma • Bleeding within meninges • Beneath dura mater & within subarachnoid space • Above pia mater • Slow bleeding • Superior sagital sinus • Signs progress over several days • Slow deterioration of mentation
Intracranial Hemorrhage Acute subdural hematoma Venous bleed Onset: hours to days Level of consciousness Fluctuations Associated symptoms Headache Focal neurologic signs High-risk Alcoholics, elderly, taking anticoagulants Head Trauma - 31
Intracranial Hemorrhage Intracerebral hemorrhage Arterial or venous Surgery is often not helpful Level of consciousness Alterations common Associated symptoms Varies with region and degree Pattern similar to stroke Headache and vomiting Head Trauma - 32
Focal Brain InjuryIntracranial Hemorrhage • Intracerebral Hemorrhage • Rupture blood vessel within the brain • Presentation similar to stroke symptoms • Signs and symptoms worsen over time
Diffuse Brain Injury • Due to stretching forces placed on individual nerve cells • Pathology distributed throughout brain • Types • Concussion • Moderate Diffuse Axonal Injury • Severe Diffuse Axonal Injury
Diffuse Brain InjuryConcussion • Mild to moderate form of Diffuse Axonal Injury (DAI) • Nerve dysfunction without anatomic damage • Transient episode of • Confusion, Disorientation, Event amnesia • Suspect if patient has a momentary loss of consciousness • Management • Frequent reassessment of mentation • ABC’s
Brain Injuries Concussion No structural injury to brain Level of consciousness Variable period of unconsciousness or confusion Followed by return to normal consciousness Retrograde short-term amnesia May repeat questions over and over Associated symptoms Dizziness, headache, ringing in ears, and/or nausea Head Trauma - 36
Diffuse Brain InjuryModerate Diffuse Axonal Injury • “Classic Concussion” • Same mechanism as concussion • Additional: Minute bruising of brain tissue • Unconsciousness • May exist with a basilar skull fracture • Signs & Symptoms • Unconsciousness or Persistent confusion • Loss of concentration, disorientation • Retrograde & Antegrade amnesia • Visual and sensory disturbances • Mood or Personality changes
Brain Injuries Diffuse axonal injury Diffuse injury Generalized edema No structural lesion Most common injury fromsevere blunt head trauma Associated symptoms Unconscious No focal deficits Head Trauma - 38
Diffuse Brain InjurySevere Diffuse Axonal Injury • Brainstem Injury • Significant mechanical disruption of nerve cells • Cerebral hemispheres and brainstem • High mortality rate • Signs & Symptoms • Prolonged unconsciousness • Cushing’s reflex • Decorticate or Decerebrate posturing
Brain Anatomy Intracranial volume Brain CSF Blood vessel volume Dilatation with high pCO2 Constriction with low pCO2 Slight effect on volume Head Trauma - 40
Intracranial Perfusion • Cranial volume fixed • 80% = Cerebrum, cerebellum & brainstem • 12% = Blood vessels & blood • 8% = CSF • Increase in size of one component diminishes size of another • Inability to adjust = increased ICP
Intracranial Perfusion • Compensating for Pressure • Compress venous blood vessels • Reduction in free CSF • Pushed into spinal cord • Decompensating for Pressure • Increase in ICP • Rise in systemic BP to perfuse brain • Further increase of ICP ICP BP
Factors Affecting ICP • Vasculature Constriction • Cerebral Edema • Systolic Blood Pressure • Low BP = Poor Cerebral Perfusion • High BP = Increased ICP • Carbon Dioxide • Reduced respiratory efficiency
Intracranial Pressure • Role of Carbon Dioxide • Increase of CO2 in CSF • Cerebral Vasodilation • Encourage blood flow • Reduce hypercarbia • Reduce hypoxia • Contributes to ICP • Reduced levels of CO2 in CSF • Cerebral vasoconstriction • Results in cerebral anoxia
Pressure & Structural Displacement • Increased pressure • Compresses brain tissue • Herniates brainstem • Compromises blood supply • Signs & Symptoms • Upper Brainstem • Vomiting • Altered mental status • Pupillary dilation • Medulla Oblongata • Respiratory • Cardiovascular • Blood Pressure disturbances
Signs & Symptoms of Brain InjuryPhysiological Changes • Upper Brainstem Compression • Increasing blood pressure • Reflex bradycardia • Vagus nerve stimulation • Cheyne-Stokes respirations • Pupils become small and reactive • Decorticate posturing • Neural pathway disruption
Signs & Symptoms of Brain InjuryPhysiological Changes • Middle Brainstem Compression • Widening pulse pressure • Increasing bradycardia • CNS Hyperventilation • Deep and Rapid • Bilateral pupil sluggishness or inactivity • Decerebrate posturing
Signs & Symptoms of Brain InjuryPhysiological Changes • Lower Brainstem Injury • Pupils dilated and unreactive • Ataxic respirations • Erratic with no pattern • Irregular and erratic pulse rate • ECG Changes • Hypotension • Loss of response to painful stimuli
Signs & Symptoms of Brain InjuryEye Signs • Physiological Issues • Indicate pressure on • CN-III (Oculomotor Nerve) • Pressure on nerve causes eyes to be sluggish, then dilated, and finally fixed • Reduced peripheral blood flow • Pupil Size & Reactivity • Reduced Pupillary Responsiveness • Depressant drugs or Cerebral Hypoxia • Fixed & Dilated • Extreme Hypoxia