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Neurotrauma. James F. Holmes, MD, MPH Professor, Department of Emergency Medicine University of California at Davis - School of Medicine Director, EM Research Fellowship Director, Department of EM Journal Club Davis, California. Objectives. Epidemiology Types of traumatic brain injuries (TBI)
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Neurotrauma James F. Holmes, MD, MPHProfessor, Department of Emergency MedicineUniversity of California at Davis - School of MedicineDirector, EM Research FellowshipDirector, Department of EM Journal ClubDavis, California
Objectives • Epidemiology • Types of traumatic brain injuries (TBI) • Diagnosis of patients with TBI • Treatment of TBI
Essentials of TBI Most traumatic deaths secondary to TBI Secondary brain injury may cause morbidity and mortality but is often preventable Initial Resuscitation and care: Maintain oxygenation Appropriate ventilation Maintain blood pressure (prevent hypotension) Cranial CT scanning is the diagnostic test of choice
Pathophysiology • Primary (initial) brain injury • Structural damage from the initial impact • Prevention strategies to minimize the number of patients sustaining head injuries • Example: motorcycle helmets
Pathophysiology Secondary brain injury Tissue injury occurring after the initial injury Usually in the initial 24 hours Hypoxia Mass effect Limited blood flow Infection Hyperthermia Treatment goal: prevent these types of insults with appropriate treatment
Pathophysiology CPP = MAP - ICP Cerebral perfusion pressure (CPP) Goal is > 70mmHg Mean Arterial Pressure (MAP) Intracranial Pressure (ICP) Intracranial pressure may be with: mass effect of a bleed generalized brain edema Cellular dysfunction occurs with decreased perfusion to the brain cells
Types of Injuries • Skull Fracture • Concussion • Contusion • Intracranial hematoma • Epidural, Subdural, Epidural, Intracerebral • Diffuse axonal injury • Intraventricular and Subarrachnoid hemorrhages • Penetrating injury
Skull Fracture • Multiple types: • Linear, depressed, and basilar • CT must be viewed on bone windows • Most important feature is injury occurring to the brain at the site of the skull fracture • Linear skull fracture: • If closed, can simply be observed
Skull Fracture • Basilar skull fracture: • Most often involving the temporal bone • Clinical diagnosis (CT often fails to show fracture) • Raccoon’s (Panda’s) eyes, hemotympanum, Battle’s sign (mastoid ecchymosis), CSF rhinorrhea • Depressed skull fracture: • Surgical elevation: • if greater than width of skull or • > 5mm
Concussion • Brief change in brain function usually with loss of consciousness/amnesia • Head CT often normal • Post-concussive syndrome: • Headache, confusion, difficulty concentrating, memory problems, nausea • May last hours to months • Treatment • Simple observation • Limit activity that may reinjure patient’s head • Avoid “repeat concussion”
Cerebral Contusion • Bruising to the brain • Most common traumatic finding on CT • Large contusions may have significant bleeding (hemorrhagic contusion or intracerebral hematoma), edema, or cause seizures • Location: Frontal and Temporal lobes • Due to irregularity of the skull base • Treatment: close observation
Epidural Hematoma (EDH) • Hemorrhage “above” the dura • Usually arterial (middle meningeal artery) but can also be from venous bleeding • CT: convex (lens shaped) area of blood • Bleeding restricted by the dura’s attachment to the skull • 5-15% of patients with TBI on CT have an EDH
Epidural Hematoma (EDH) • Potentially rapidly expanding with mass effect and uncal herniation (fixed/dilated pupil) • “Awake and then die” • Most EDHs can be observed • EDHs with mass effect require surgical drainage
Subdural Hematoma (SDH) • Hemorrhage between the dura and the brain • More common than EDH • 30% of patients with TBI have a SDH • CT: Crescent shaped area of blood • Can be acute, subacute or chronic • Subacute or chronic presents days/weeks after injury
Subdural Hematoma (SDH) • Elderly at risk (less severe mechanisms) • Brain shrinks with age resulting in stretching of the bridging veins in the subdural space • May gradually enlarge (slower than EDH) • Surgical drainage for lesions resulting in masse effect and shift
Intracerebral Hematoma • Similar to cerebral contusions • More severe type injury • Bleeding within the brain itself • Frontal and temporal lobes • Close observation for progression of bleeding • May cause mass effect that results in herniation
Intraventricular Hemorrhage (IVH) • Collection of blood in the ventricles • Isolated IVH usually not problematic and requires no specific treatment
Subarrachnoid Hemorrhage (SAH) • SAH and contusion are most common injuries on CT after blunt trauma • CT: blood in the sulci and basal cisterns • Often associated with intracranial hematomas • Must consider that the SAH caused the trauma (spontaneous bleed and then fall) • Complications: • Arterial vasospasm: 2-3 days after injury
Diffuse Axonal Injury (DAI) • Shearing and rotational forces disrupt the axonal network • Mechanism: rapid acceleration/deceleration injury • Imaging • Not well visualized by CT • MRI can better define the extent of injury • No specific therapy • Likely results in the persistent neurologic deficits in patients with normal CT scans but substantial injury
Penetrating Injury • Primarily gunshot wounds (GSWs) but also from stab wounds (SWs) • Higher rate in urban areas • Injuries that cross the midline have very poor outcomes • Periorbital/nasal region risk of infection
Epidemiology of Head Injury • Varies by country, but in general: • Most common in males (ages 15-30 years) • Highest rates of TBI on CT in: • elderly (>65 years) • young (<10 years) • Mechanisms of injury: • Motor vehicle crash (including pedestrian/bike) • Falls (especially the young and elderly) • Assaults • Alcohol frequently involved
Classification of Neurotrauma • Multiple different classification schemes • Minimal • GCS = 15, No loss of consciousness • Normal alertness, memory and neuro exam • No evidence of skull fracture • Mild • Brief loss of consciousness, amnesia • GCS = 14 • Impaired alertness, memory • No evidence of skull fracture
Classification of Neurotrauma • Moderate or potentially severe • Prolonged (>5 minutes) loss of consciousness • GCS 9-13 • Focal neurological deficit • Post-traumatic seizure • Intracranial lesion on CT scan • Palpable depressed skull fracture • Severe: • GCS < 8 • Requires airway control
Prehospital Care • Initial GCS score • Spine immobilization • Airway management for moderate/severe head injury • Bag valve mask with oxygen to assist with ventilation • Endotracheal intubation not shown to help • Suggests harm in multiple studies
History • Mechanism of injury • any seizure after the event? • Prehospital care • Medications given (and times) • Spine immobilization • Medical history • Allergies • Medications • Especially anticoagulant medications • Tetanus
Primary Survey • Standard ATLS (A, B, C, D, E) • Assign a GCS score to the patient • May use AVPU scale • Alert • Verbal stimuli • Painful stimuli • Unresponsive • Cervical spine protection • Movement in all extremities if patient to be paralyzed for airway management
Primary Survey: Airway Managment • Most common reason for intubation in trauma • Rapid Sequence Intubation is standard in USA • Premedications • Lidocaine: 1-2mg/kg IV 3-4 minutes prior, potentially protects the rise in ICP with intubation • Sedatives • Etomidate: 0.3mg/kg, no effects on blood pressure • Benzodiazepines/Thiopental: volume status must be normal • Paralytics • Succinylcholine: 1-1.5mg/kg, paralysis for 5 minutes • Rocuronium: 1 mg/kg, paralysis for 20-30 minutes
Secondary Survey • Formal (repeat) GCS score • Pupil examination • General neurological examination • Cranial nerves • Motor exam • Sensory exam • Reflexes
Secondary Survey • Head examination: • Lacerations and possible skull fracture • Evaluation for Basilar skull fracture • Hemotympanum • Raccoon’s (panda’s) eyes • Battle’s sign – mastoid ecchymosis, often takes > 12 hours to develop • CSF from the nose: • Halo test: drop of fluid onto a towel, central spot bloody with surrounding tint (CSF) • CSF contains glucose, nasal secretions do not
Diagnostic Testing • CT scan: • Primary screening tool • Has decreased morbidity and mortality • Images viewed in bone and brain windows • Images rapidly obtained (<1 minute on fast CT scanners) • Exposes the patient to large amounts of radiation • Costly
Diagnostic Testing • CT scan: • Alert patients with normal CT scans are at very low risk for neurologic deterioration • Safe to discharge home from the ED • CT limitations: • Ability to detect diffuse axonal injury • No information on blood flow to the brain
Diagnostic Testing • Skull radiographs: • May localize a foreign body • low utility and generally not performed in those at risk for brain injury • Consider in very young children (<1 year) who appear well but only have a hematoma to head
Diagnostic Testing • MRI: • Better than CT • May show diffuse axonal injury and injuries not identified by CT scan • Not used as a routine screening test • 30 – 45 minutes to obtain images • Very costly and not always available