Mechanisms of brain injury Evaluation of head injury

Definitions

• Definitions

• Glasgow Coma Scale
• Intracranial Pressure

• Mechanisms of brain injury

• Evaluation of head injury

• Management of head injury

• Operative
• Nonoperative

1995 – 1st edition

• 1995 – 1st edition

• 2000 – 2nd edition

• 2007 – 3rd edition

• Level I – Accepted principles reflecting high degree of clinical certainty

• Level II – Strategies reflecting moderate degree of clinical certainty

• Level III – Degree of clinical certainty not established

Definitions

• Definitions

• Glasgow Coma Scale
• Intracranial Pressure

• Mechanisms of brain injury

• Evaluation of head injury

• Management of head injury

• Operative
• Nonoperative

Introduced by Teasdale and Jennett in 1974

• Introduced by Teasdale and Jennett in 1974

• Consists of 3 clinical signs that have

• Prognostic significance
• Good reproducibility between observers

• Scale range 3-15

• GCS < 8 has generally become accepted as representing coma / severe head injury

Normal CPP > 50 mm Hg

• Normal CPP > 50 mm Hg

• Autoregulatory mechanisms maintain CBF at CPP’s down to 40 mm Hg

In head injury, ICP > 20-25 mm Hg may be more detrimental than low CPP (increasing CPP may not afford protection from intracranial hypertension).

• In head injury, ICP > 20-25 mm Hg may be more detrimental than low CPP (increasing CPP may not afford protection from intracranial hypertension).

• Aggressive attempts to maintain CPP > 70 should be avoided due to ARDS (Level II)

• CPP<50 should be avoided (Level III)

Definitions

• Definitions

• Glasgow Coma Scale
• Intracranial Pressure

• Mechanisms of brain injury

• Evaluation of head injury

• Management of head injury

• Operative
• Nonoperative

Impact injury

• Impact injury

• Cerebral or brainstem contusions
• Cerebral lacerations
• Diffuse axonal injury (DAI)

• Secondary injury

• Intracranial hematoma
• Edema
• Ischemia

Statistics

• Statistics

• Definitions

• Glasgow Coma Scale
• Intracranial Pressure

• Mechanisms of brain injury

• Evaluation of head injury

• Management of head injury

• Operative
• Nonoperative

History

• History

• LOC +/-
• Intoxicants
• Seizure
• Posttraumatic amnesia

CT

• CT

• Imaging study of choice for initial work-up

• MRI

• More helpful later in hospital course

• Skull x-rays

• Arteriography

Presence of any criteria placing patient at moderate or high risk for intracranial injury

• Presence of any criteria placing patient at moderate or high risk for intracranial injury

• Assessment prior to general anesthesia for other procedures

Definitions

• Definitions

• Glasgow Coma Scale
• Intracranial Pressure

• Mechanisms of brain injury

• Evaluation of head injury

• Management of head injury

• Operative
• Nonoperative

Nonoperative

• Nonoperative

• Seen in absence of significant intracranial mass lesion.
• Typically consists of assessment and/or treatment of intracranial pressure (ICP).

• Operative

• Typically required when a significant intracranial mass lesion is present.
• Decompressive craniectomy or brain resection less common.

Nonoperative

• Nonoperative

• Seen in absence of significant intracranial mass lesion.
• Typically consists of assessment and/or treatment of intracranial pressure (ICP).

• Operative

• Typically required when a significant intracranial mass lesion is present.
• Decompressive craniectomy or brain resection less common.

Frequent neuro checks

• Frequent neuro checks

• Frequent neuro checks

• Frequent neuro checks

• ICP monitoring

No data to support Level I recommendation

• No data to support Level I recommendation

• Severe head injury (GCS 3-8) with abnormal CT (Level II)

• Severe head injury (GCS 3-8) with normal CT and 2 of the following (Level III):

• Age > 40 years
• Unilateral or bilateral motor posturing
• SBP < 90 mm Hg

• Mild-moderate head injury at discretion of treating physician

Loss of neurological examination

• Loss of neurological examination

• Sedation
• General anesthesia

20 y.o. male in MVA

• 20 y.o. male in MVA

• Intubated
• Score 1T
• Eyes open to pain
• Score 2
• Briskly localizes
• Score 5
• Total GCS 8T

First tier

• First tier

• Positioning
• Ventricular drainage
• Osmotic diuresis
• Hyperventilation (Level III – temporizing measure)

• Second tier

• Sedation
• Neuromuscular blockade
• Hypothermia
• Barbiturate coma

• Glucocorticoids not recommended (Level I)

Nonoperative

• Nonoperative

• Seen in absence of significant intracranial mass lesion.
• Typically consists of assessment and/or treatment of intracranial pressure (ICP).

• Operative

• Typically required when a significant intracranial mass lesion is present.
• Decompressive craniectomy or brain resection less common.

Types of mass lesions

• Types of mass lesions

• Epidural hematoma
• Subdural hematoma
• Cerebral contusion

• Decompressive craniectomy/brain resection

1% of head trauma admissions

• 1% of head trauma admissions

• Male: Female = 4:1

• Source of bleeding is arterial in 85% of cases (middle meningeal artery)

• Mortality ranges from 5-10% with optimal management

• Neurological injury caused by secondary mechanisms

About twice as common as EDH

• About twice as common as EDH

• Mortality 50-90%

• Impact injury much higher than with EDH
• Often associated brain injury

• Two common sources of bleeding

• Tearing of bridging veins
• Cortical laceration

Often little mass effect

• Often little mass effect

• Not often operative

2 mechanisms of brain injury

• 2 mechanisms of brain injury

• Impact injury
• Secondary injury

• GCS < 8 has generally become accepted as representing coma / severe head injury

• CT is generally the imaging study of choice in the acute assessment of head injury

• Operative and nonoperative strategies are generally aimed at reducing mass effect and, therefore, reducing ICP

• Nothing beats a neuro exam.