CHAPTER 6

HEAD TRAUMA

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

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

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 )

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 )

Anatomy & Physiology Brain

– Cerebrum1. Frontal: emotion, motor function &

expression of speech ( motor speech areas )

2. Parietal: sensory & spatial orientation3. Temperal: memory function, responsible

for speech4. Occipital: vision

– Brain Stem1. Midbrain: reticular activating system2. Pons: reticular activating system3. Medulla: cardiorespiratory center4. Cerebellum: coordiration & balance

Anatomy & Physiology

Tentorium

– Supratentorial compartment ( anterior

& middle cranial fossa )» Uncal herniation ( Supratentorial

pressure ): ipsilateral pupillary dilation & contralateral hemiplegia

– Infratentorial compartment ( posterior

fossa )

Anatomy & Physiology

Intracranial Pressure: Hemostasis

Kicp VCSF + VBl + VBr

Pitfalls:

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

Pressure / Volume Curve

ICP Herniation

10 point of decompensation

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

Intracranial Pressure

Increased Intracranial Pressure( IICP )

Result in

– Decreased cerebral perfusion

pressure ( CPP )

»CPP : Mean Arterial Blood

Pressure-

ICP

– Altered level of consciousness

Anatomy & Physiology

Autoregulation of Cerebral blood flow ( CBF ) Noninjured person:

CBF is consiant between mean bloodpressure of 50 and 160 mm Hg

Head-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 Injury

Mechanism of injury

Severity of injury

Morphology of injury ( base on CT

scan )

Classification of Head Injury

Mechanism of injury– Blunt:

automobile collision, fall & assault– Penetrating:

gunshot wounds, other penetrating

injuries

Classification of Head Injury

Severity

– Coma: GCS sore =< 8

– Mild: GCS score 14 ~ 15

– Moderate: GCS score 9 ~13

– Severe: GCS score 3 ~ 8

Classification of Head Injury

Morphology of Injury– Skull fractures– Intracranial lesions

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

Intracranial Lesions

Focal lesions Diffuse lesions

Intracranial Lesions

Focal lesions: Epidural hematoma:

– most due to tearing of the middle meningeal artery– prognosis is usually excellent ( underlying brain injury is li

mited )– CT: biconvex or lenticular in shape– Pitfalls: classical lucid interval and ‘talk and die’

Intracranial Lesions

Focal lesions Subdural hematoma:

– brain damage much more & prognosis is much worse than EDH

– tearing of a bridging vein

Intracranial Lesions

Focal lesions Contusions and intracerebral hematomas:

– most occur in the frontal & temporal lobes– always seen in association with SDH

Intracranial Lesions

Diffuse injuries– Mild concussion: temporary neurologic dysfunction, confusi

on & 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 events3.post-concussion syndrome: memory difficulties, dizziness,

nausea, anosmia & depression

Intracranial Lesions

Diffuse 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 injury

History Mechanism of injury Pre and post injury status Document / communicate Reassess

Assessment

Vital Signs Identifies neurologic & systemic

status Presume hypotension due to

hypovolemia, not head injury

Minineurologic Exam

Purpose Determine severity of brain injury Detect deterioration Categories injuries

Minineurologic Exam

Level of consciousness - GCS– eye opening– verbal – motor

Pupil Motor lateralization ( mass lesion )

Minineurologic Exam

Pupils Equality Briskness of response Anormal: >1 mm difference in size

Minineurologic Exam

Extremity Movement Equality Pain response Lateralized weakness - mass lesion

Minineurologic Exam

Repeat & compare Detect deterioration initiate treatment Neurosurgical Consultation

Minineurologic Exam

Don’t presume altered status due to alcohol / drugs ingestion

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

Head injury Management

Management Goals Establish diagnosis Assure brain metabolism & prevent

secondary brain injury Consult Neurosurgen early or early transfer

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

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

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

Head injury Management

Management of Severe Head Injury GCS 3 ~ 8 Prompt diagnosis & treatment is of utmost import ( wait and see = dis

astrous ) Primary survey : Cardiopulmonary stabilization be achieved rapidly Secondary survey : >= 50 % had additional major systemic injury Minineurologic Examination : reliable minineurologic examination pri

or to sedating or paralying the patient

Medical Therapies for Head Injury

Goal:To prevent secondary damage to an already injuried brain

Medical Therapies for Head Injury

Intravenous Fluid:– 1. Keep euvolemic status, dehydration is more harmful ( vi

tal 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 )

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

Medical Therapies for Head Injury

Steroid :– Not demonstrated any beneficial effect

Anticonvulsants– High incidence of Late epilepsy:

1. Early seizure occurring within the first week2. An intracranial hematoma3. Depressed skull fracture

– phenytoin reduce the incidence of seizure in the first week of injury but not thereafter

Restlessness

Identify etiology:– Pain – Hypoxia or shock

Correct cause:– Analgesics / Sedatives– Ventilation / Treat shock

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 gl

ucose-containing fluid ) keep euvolemic status

Summary

Avoid the use of long-acting paralytic agents Perform a minineurologic examination after stabilizing the bloo

d pressure and before paralying the patient Exclude cervical spine injury Contact a neurosurgeon as early as possible Frequently reassess the patient’s neurologic status