CHAPTER 6

1. CHAPTER 6 HEAD TRAUMA

2. OBJECTIVES • A. 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

3. Introduction • 10 % of head injury die prior to reaching a hospital • Head 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

4. Neurosurgen need know 1. Age of patient & the mechanism and time of injury 2. Vital signs ( particular the blood pressure ) 3. Results of minineurologic examination ( GCS score; particular the motor response, and pupillary reaction ) 4. Associated injury 5. Results of the diagnostic studies ( CT scan )

5. Anatomy & Physiology • SCALP • S: Skin • C: Connective tissue • A: Aponeurosis / galea aponeurotica • L: Loose areolar tissue • P: Pericranium • Pitfalls Bleeding from Scalp laceration will result in shock ( especialling in children )

6. Anatomy & Physiology • Brain • Cerebrum 1. Frontal: emotion, motor function & expression of speech ( motor speech areas ) 2. Parietal: sensory & spatial orientation 3. Temperal: memory function, responsible for speech 4. Occipital: vision • Brain Stem 1. Midbrain: reticular activating system 2. Pons: reticular activating system 3. Medulla: cardiorespiratory center 4. Cerebellum: coordiration & balance

7. Anatomy & Physiology • Tentorium • Supratentorial compartment ( anterior & middle cranial fossa ) • Uncal herniation ( Supratentorial pressure ): ipsilateral pupillary dilation & contralateral hemiplegia • Infratentorial compartment ( posterior fossa )

8. Anatomy & Physiology • Intracranial Pressure: Hemostasis Kicp VCSF + VBl + VBr Pitfalls: A normal intracranial pressure dose not necessarily exclude a mass lesion ( compensation stage )

9. Intracranial Pressure Pressure / Volume Curve ICPHerniation 10 point of decompensation volume of mass keep the patient’s pressure & volume in the flat portion of the curve, rather than to treat the patient at the point of decompensation

10. Increased Intracranial Pressure( IICP ) Result in • Decreased cerebral perfusion pressure ( CPP ) • CPP : Mean Arterial Blood Pressure- ICP • Altered level of consciousness

11. Anatomy & Physiology Autoregulation of Cerebral blood flow ( CBF ) • Noninjured person: CBF is consiant between mean blood pressure of 50 and 160 mm Hg • Head-injured patient: autoregulation is often disturbed, so he vulnerable to secondary brain injury due to ischemia from hypotensive episode ( keep vital signs is very important )

12. Classification of Head Injury • Mechanism of injury • Severity of injury • Morphology of injury ( base on CT scan )

13. Classification of Head Injury Mechanism of injury • Blunt: automobile collision, fall & assault • Penetrating: gunshot wounds, other penetrating injuries

14. Classification of Head Injury Severity • Coma: GCS sore =< 8 • Mild: GCS score 14 ~ 15 • Moderate: GCS score 9 ~13 • Severe: GCS score 3 ~ 8

15. Classification of Head Injury Morphology of Injury • Skull fractures • Intracranial lesions

16. Skull fractures • Vault: linear / stellate, depressed / nondepressed, open / close • Basilar (diagnosed by CT bone window): raccoon eyes, Battle’s signs (retroauricular ecchymosis), CSF leakage and 7th nerve palsy

17. Intracranial Lesions • Focal lesions • Diffuse lesions

18. Intracranial Lesions Focal lesions: • Epidural hematoma: • most due to tearing of the middle meningeal artery • prognosis is usually excellent ( underlying brain injury is limited ) • CT: biconvex or lenticular in shape • Pitfalls: classical lucid interval and ‘talk and die’

19. Intracranial Lesions Focal lesions • Subdural hematoma: • brain damage much more & prognosis is much worse than EDH • tearing of a bridging vein

20. Intracranial Lesions Focal lesions • Contusions and intracerebral hematomas: • most occur in the frontal & temporal lobes • always seen in association with SDH

21. Intracranial Lesions Diffuse injuries • Mild concussion: temporary neurologic dysfunction, confusion & disorientation without or with amnesia • Classic cerebral concussion: 1.Transient & reversible loss of consciousness, returns to full consciousness by 6 hrs. 2.No sequelae other than amnesia for the events 3.post-concussion syndrome: memory difficulties, dizziness, nausea, anosmia & depression

22. Intracranial Lesions Diffuse injuries: • Diffuse axonal injury ( DAI ) 1.prolonged postraumatic coma that is not due to a mass lesion or ischemic insults 2.usually having decortication or decerebation posture 3.autonomic dysfunction: hypertension, hyperhidrosis & hyperpyrexia

23. Assessment of Head injury History • Mechanism of injury • Pre and post injury status • Document / communicate • Reassess

24. Assessment Vital Signs • Identifies neurologic & systemic status • Presume hypotension due to hypovolemia, not head injury

25. Minineurologic Exam Purpose • Determine severity of brain injury • Detect deterioration • Categories injuries

26. Minineurologic Exam • Level of consciousness - GCS • eye opening • verbal • motor • Pupil • Motor lateralization ( mass lesion )

27. Minineurologic Exam Pupils • Equality • Briskness of response • Anormal: >1 mm difference in size

28. Minineurologic Exam Extremity Movement • Equality • Pain response • Lateralized weakness - mass lesion

29. Minineurologic Exam • Repeat & compare • Detect deterioration • initiate treatment • Neurosurgical Consultation

30. Minineurologic Exam Don’t presume altered status due to alcohol / drugs ingestion

31. Diagnostic Procedure • CT: • be obtained in all head -injury patients ( ideally ), especially there is a history of more than a momentary loss of consciousness, amnesia or severe headaches • C-Spine • Alcohol level & urine toxic screen • Skull X-ray: • penetrating head injury or when CT scan is not immediately available

32. Head injury Management Management Goals • Establish diagnosis • Assure brain metabolism & prevent secondary brain injury • Consult Neurosurgen early or early transfer

33. Head injury Management Management of Mild head injury • Normal CT : 1. Brought back to ER if need ( Head- injury warning discharge instructions ) 2. No companion ==> Admission or observe at ER • Abnormal CT : Admission

34. Head-injury Warning discharge Instruction • Drowsiness or increasing difficulty in awaking patient ( Awaken patient every 2 hrs ) • Nausea or Vomiting • Convulsion or fits • Bleeding or Watery discharge from the nose or ear • Severe headache • Weakness or loss of feeling in the arm or leg • Confusion or strange behavior • One pupil larger than the other, double vision or visual disturbance • Very slow or very rapid pulse, or an unusual breathing pattern

35. Head injury Management Management of Moderate Head Injury • GCS 9 ~ 13 • All need brain CT • All need to be admitted, even if CT scan is normal

36. Head injury Management Management of Severe Head Injury • GCS 3 ~ 8 • Prompt diagnosis & treatment is of utmost import ( wait and see = disastrous ) • Primary survey : Cardiopulmonary stabilization be achieved rapidly • Secondary survey : >= 50 % had additional major systemic injury • Minineurologic Examination : reliable minineurologic examination prior to sedating or paralying the patient

37. Medical Therapies for Head Injury Goal: To prevent secondary damage to an already injuried brain

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

39. Medical Therapies for Head Injury Mannitol: • Indication: • 1. Comatous patient who initially has normal, reactive pupils, but the develops pupillary dilatation with or without hemiparesis • 2. Patient with bilaterally dilated and nonreactive pupils who are not hypotensive • Dose ( bolus ) : 1 g/Kg • Lasix : Be used in consultation with a neurosurgeon

40. Medical Therapies for Head Injury • Steroid : • Not demonstrated any beneficial effect • Anticonvulsants • High incidence of Late epilepsy: 1. Early seizure occurring within the first week 2. An intracranial hematoma 3. Depressed skull fracture • phenytoin reduce the incidence of seizure in the first week of injury but not thereafter

41. Restlessness • Identify etiology: • Pain • Hypoxia or shock • Correct cause: • Analgesics / Sedatives • Ventilation / Treat shock

42. Summary • In a comatose patient, secure & maintain airway ( endotracheal intubation ) • Moderately hyperventilation, keep PaCO2 at 25~35 mmHg • Treat shock aggressively • Resuscitate with normal saline or Ringer’s lactate ( avoid hypotonic or glucose-containing fluid ) • keep euvolemic status

43. Summary • Avoid the use of long-acting paralytic agents • Perform a minineurologic examination after stabilizing the blood pressure and before paralying the patient • Exclude cervical spine injury • Contact a neurosurgeon as early as possible • Frequently reassess the patient’s neurologic status