CHAPTER 6HEAD TRAUMA

OBJECTIVESA.Understand basic intracranial anatomy & physiology

B.Evaluate a patient with a head injury

C.Perform the necessary stabilization procedures

D.Determine the appropriate disposition of the patient

Introduction10 % of head injury die prior to reaching a hospitalHead injury can be divided:mild ( 80 % )moderate (10 % )severe (10 % )avoid secondary brain damage ( support vital signs, avoid & treat IICP )Obtaining a CT Scan should not delay patient transfer ( transfer patient early )Neurosurgical consult essential

Neurosurgen need know1.Age of patient & the mechanism and time of injury2.Vital signs ( particular the blood pressure )3.Results of minineurologic examination ( GCS score; particular the motor response, and pupillary reaction )4.Associated injury5.Results of the diagnostic studies ( CT scan )

Anatomy & PhysiologySCALPS: SkinC: Connective tissueA: Aponeurosis / galea aponeuroticaL: Loose areolar tissueP: PericraniumPitfallsBleeding from Scalp laceration will result in shock ( especialling in children )

Anatomy & PhysiologyBrainCerebrum1. Frontal: emotion, motor function & expression of speech ( motor speech areas )2. Parietal: sensory & spatialorientation3. Temperal: memory function, responsible for speech4. Occipital: visionBrain Stem1. Midbrain: reticular activating system2. Pons: reticular activating system3. Medulla: cardiorespiratory center4. Cerebellum: coordiration & balance

Anatomy & PhysiologyTentoriumSupratentorial compartment ( anterior & middle cranial fossa )Uncal herniation ( Supratentorial pressure ): ipsilateral pupillary dilation & contralateral hemiplegiaInfratentorial compartment ( posterior fossa )

Anatomy & PhysiologyIntracranial Pressure: Hemostasis

Kicp VCSF + VBl + VBr

Pitfalls:A normal intracranial pressure dose not necessarily exclude a mass lesion ( compensation stage )

Intracranial PressurePressure / Volume CurveICP Herniation

10 point of decompensation

volume of masskeep the patients pressure & volumein the flat portion of the curve, rather than to treat the patient at the point ofdecompensation

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Increased Intracranial Pressure( IICP )Result inDecreased cerebral perfusion pressure ( CPP ) CPP : Mean Arterial Blood Pressure- ICPAltered level of consciousness

Anatomy & PhysiologyAutoregulation of Cerebral blood flow ( CBF )Noninjured person:CBF is consiant between mean bloodpressure of 50 and 160 mm HgHead-injured patient:autoregulation is often disturbed, so hevulnerable to secondary brain injury due to ischemia from hypotensive episode ( keep vital signs is very important )

Classification of Head InjuryMechanism of injurySeverity of injuryMorphology of injury ( base on CT scan )

Classification of Head InjuryMechanism of injuryBlunt: automobile collision, fall & assaultPenetrating: gunshot wounds, other penetrating injuries

Classification of Head InjurySeverityComa:GCS sore =< 8Mild:GCS score 14 ~ 15Moderate:GCS score 9 ~13Severe:GCS score 3 ~ 8

Classification of Head InjuryMorphology of InjurySkull fracturesIntracranial lesions

Skull fracturesVault:linear / stellate, depressed / nondepressed,open / closeBasilar (diagnosed by CT bone window):raccoon eyes, Battles signs (retroauricular ecchymosis), CSF leakage and 7th nerve palsy

Intracranial LesionsFocal lesionsDiffuse lesions

Intracranial LesionsFocal lesions:Epidural hematoma:most due to tearing of the middle meningeal arteryprognosis is usually excellent ( underlying brain injury is limited )CT: biconvex or lenticular in shapePitfalls: classical lucid interval and talk and die

Intracranial LesionsFocal lesionsSubdural hematoma:brain damage much more & prognosis is much worse than EDHtearing of a bridging vein

Intracranial LesionsFocal lesionsContusions and intracerebral hematomas:most occur in the frontal & temporal lobesalways seen in association with SDH

Intracranial LesionsDiffuse injuriesMild concussion: temporary neurologic dysfunction, confusion & disorientation without or with amnesiaClassic cerebral concussion:1.Transient & reversible loss of consciousness, returns to full consciousness by 6 hrs.2.No sequelae other than amnesia for the events3.post-concussion syndrome: memory difficulties, dizziness, nausea, anosmia & depression

Intracranial LesionsDiffuse injuries:Diffuse axonal injury ( DAI )1.prolonged postraumatic coma that is not due to a mass lesion or ischemic insults2.usually having decortication or decerebation posture3.autonomic dysfunction: hypertension, hyperhidrosis & hyperpyrexia

Assessment of Head injuryHistoryMechanism of injuryPre and post injury statusDocument / communicateReassess

AssessmentVital SignsIdentifies neurologic & systemic statusPresume hypotension due to hypovolemia, not head injury

Minineurologic ExamPurposeDetermine severity of brain injuryDetect deteriorationCategories injuries

Minineurologic ExamLevel of consciousness - GCSeye openingverbal motorPupilMotor lateralization ( mass lesion )

Minineurologic ExamPupilsEqualityBriskness of responseAnormal: >1 mm difference in size

Minineurologic ExamExtremity MovementEqualityPain responseLateralized weakness - mass lesion

Minineurologic ExamRepeat & compareDetect deterioration initiate treatmentNeurosurgical Consultation

Minineurologic Exam Dont presume altered status due to alcohol / drugs ingestion

Diagnostic ProcedureCT:be obtained in all head -injury patients ( ideally ), especially there is a history of more than a momentary loss of consciousness, amnesia or severe headachesC-SpineAlcohol level & urine toxic screenSkull X-ray:penetrating head injury or when CT scan is not immediately available

Head injury ManagementManagement GoalsEstablish diagnosisAssure brain metabolism & prevent secondary brain injuryConsult Neurosurgen early or early transfer

Head injury ManagementManagement of Mild head injuryNormal CT :1.Brought back to ER if need ( Head-injury warning discharge instructions )2.No companion ==> Admission or observe at ERAbnormal CT : Admission

Head-injury Warning discharge InstructionDrowsiness or increasing difficulty in awaking patient ( Awaken patient every 2 hrs )Nausea or VomitingConvulsion or fitsBleeding or Watery discharge from the nose or earSevere headacheWeakness or loss of feeling in the arm or legConfusion or strange behaviorOne pupil larger than the other, double vision or visual disturbanceVery slow or very rapid pulse, or an unusual breathing pattern

Head injury ManagementManagement of Moderate Head InjuryGCS 9 ~ 13All need brain CTAll need to be admitted, even if CT scan is normal

Head injury ManagementManagement of Severe Head InjuryGCS 3 ~ 8Prompt diagnosis & treatment is of utmost import ( wait and see = disastrous )Primary survey : Cardiopulmonary stabilization be achieved rapidlySecondary survey : >= 50 % had additional major systemic injuryMinineurologic Examination : reliable minineurologic examination prior to sedating or paralying the patient

Medical Therapies for Head InjuryGoal:To prevent secondary damage to an already injuried brain

Medical Therapies for Head InjuryIntravenous Fluid:1. Keep euvolemic status, dehydration is more harmful ( vital signs stable )2. Not to use hypotonic or glucose-containing fluidsHyperventilation:1. Keep PaCO2 at 25~30 mmHg when the presence of raised ICP2. PaCO2 < 25 mmHg is avoided ( vasoconstriction ==> CBF )

Medical Therapies for Head InjuryMannitol:Indication:1. Comatous patient who initially has normal, reactive pupils, but the develops pupillary dilatation with or without hemiparesis2. Patient with bilaterally dilated and nonreactive pupils who are not hypotensiveDose ( bolus ) : 1 g/KgLasix : Be used in consultation with a neurosurgeon

Medical Therapies for Head InjurySteroid :Not demonstrated any beneficial effectAnticonvulsantsHigh incidence of Late epilepsy:1. Early seizure occurring within the first week2. An intracranial hematoma3. Depressed skull fracturephenytoin reduce the incidence of seizure in the first week of injury but not thereafter

RestlessnessIdentify etiology:Pain Hypoxia or shock

Correct cause:Analgesics / SedativesVentilation / Treat shock

SummaryIn a comatose patient, secure & maintain airway ( endotracheal intubation )Moderately hyperventilation, keep PaCO2 at 25~35 mmHgTreat shock aggressivelyResuscitate with normal saline or Ringers lactate ( avoid hypotonic or glucose-containing fluid )keep euvolemic status

SummaryAvoid the use of long-acting paralytic agentsPerform a minineurologic examination after stabilizing the blood pressure and before paralying the patientExclude cervical spine injuryContact a neurosurgeon as early as possibleFrequently reassess the patients neurologic status