Traumatic Brain Injury Dr. Kahvithaa

Definition

• is a nondegenerative, noncongenital insult to the brain from an external mechanical force, possibly leading to permanent or temporary impairment of cognitive, physical, and psychosocial functions, with an associated diminished or altered state of consciousness.

• Often, the term brain injury is used synonymously with head injury, which may not be associated with neurologic deficits

Types

• Primary brain injury - the initial injury to the brain as a direct result of the trauma

• Secondary brain -any subsequent injury to the brain after the initial insult-eg; Hypoxia and hypotension

• The treatment of head injury is directed at either preventing or minimizing secondary brain injury

Causes of Secondary Brain Injury

• Hypoxia ; PaO2 < 8kPa(60mmHg) • Hypotension; SBP < 90mmHg• Raised ICP ; ICP > 20mmHg • Low Cerebral Perfusion Pressure (CPP)

CPP < 65mmHg • Pyrexia • Seizures• Metabolic Disturbances

Classification of severity of head injury

The GCS is often used to help define the severity of TBIMild ; GCS 13 – 15 Moderate ; 9-12Severe ; 8 and below-a general guide to the level of injury.

Monro-Kellie DoctrineThe total volume of The total volume of

intracranial content intracranial content must remain must remain constant as the constant as the cranium is non-cranium is non-expansile boxexpansile box

Normal cerebral blood flow is 55 ml/100gm/min

Normal ICP is 8-12 mmHg

Relationship between Intracranial pressure and intracranial volume

Pathophysiology

• A second crucial concept in TBI pathophysiology is the concept of cerebral perfusion pressure (CPP).

• CPP = MAP - ICP• In the noninjured brain in individuals without

long-standing hypertension, cerebral blood flow (CBF) is constant in the range of MAPs of 50-150 mm Hg.

Taking a history

• Mechanism of injury • Loss of consciousness or amnesia • Level of consciousness at the scene and on transfer• Evidence of seizures • Probable hypoxia or hypotension• Pre-existing medical conditions, insulin use • Medications esp Anticoagulants • Illicit drugs and alcohol

On Examination• Glasgow coma scale • Pupil size and response • Lateralising signs• Signs of basal skull fracture

-Bilateral periorbital oedema(raccoon eyes)- Battle’s sign(bruising over mastoid)-Cerebrospinal fluid rhinorrrhoea or otorrhoea-Haemotympanum or bleeding from ear

• Full neurological examination ; tone , power, sensation , reflexes

Battle’s sign

Investigations

• Blood I/X > Standard - FBC , RP, coagulation profile - ABG -Drug toxicology -Blood alcohol level

• Computerised Tomography(CT) Scanning-The standard CT scan > non-contrast scan--identify an intracranial haematoma, scalp soft tissue injury, skull # including bass of skull #, small contusions(lesions which may not need op)

• Magnetic Resonance Imaging(MRI)-long acquisition times -difficulty in obtaining MRIs in persons who are critically ill.-It is superior to CT scan for helping identify diffuse axonal injury (DAI) and small intraparenchymal contusions.

Cerebral contusion Cerebral laceration

SDH and EDH

Management of Moderate to severe head injury

• Begins with Resuscitation and a primary survey• Aim ; prevention of the secondary brain injury

-Avoidance of hypoxia and hypotension• Cervical spine must be immobilised till Cervical spine # has

been ruled out (request for CT cervical spine in cases of doubt)

• Done primary survey >> established presence of moderate to severe head injury >> CT scan

• CT scan aims Early consultation to neurosurgical team

• Simple measures to reduce ICP eg. Positioning

Primary survey• Airway assessments with C-Spine control • Breathing and ventilation • Circulation and Haemorrhage control• Disability and Neurological deficit

- AVPU• Exposure /Environmental Control

Secondary Survey• History : AMPLE• Neurological Assessment

- GCS-pupils

• Head-to-toe examination-Head and face-Neck-Chest-Abdomen-Limbs-Back-Buttocks, perineum, genitalia

15

HistoryExamination

LOC > 5 min? Depressed skull #Lateralising signs

Observe for 6 hours

No

Discharge with Head

chart

Yes

14 13

CT Head (Non-contrast)

GCS 12 or lessMultiple System Injuries

Isolated head injury

Check and clear A & B C

If haemodynamically unstable

CXR FAST or DPL PXR Limbs

Surgery Angioembolisation+/- Ext Fixation Splint

Once C fixed

Then D CT Brain and C-Spine

< 20 min

NICE GUIDELINES

CT Brain in Head InjuryA head injury + any of the following risk factors ; perform a CT head scan within 1 hour of the risk factor being identified:

•GCS less than 13 on initial assessment in the emergency department.•GCS less than 15 at 2 hours after the injury on assessment in the emergency department.•Suspected open or depressed skull fracture.•Any sign of basal skull fracture •Post-traumatic seizure.•Focal neurological deficit.•More than 1 episode of vomiting.

For adults with any of the following risk factors + LOC or amnesia

> perform a CT head scan within 8 hours of the head injury•Age 65 years or older.•Any history of bleeding or clotting disorders.•Dangerous mechanism of injury •More than 30 minutes' retrograde amnesia of events immediately before the head injury.

When to intubate? •Coma (GCS 8 or less)•Loss of protective laryngeal reflexes.•Ventilatory insufficiency as judged by blood gases: hypoxaemia (PaO2 < 13 kPa on oxygen) or hypercarbia (PaCO2 > 6 kPa).

•Spontaneous hyperventilation causing PaCO2 < 4 kPa.•Irregular respirations.

Admission • new, clinically significant abnormalities on imaging.• GCS has not returned to 15 after imaging, regardless of

the imaging results.• has indications for CT scanning but cannot be done

within the Eg . CT is not available , or pt not cooperative • Continuing worrying signs Eg persistent vomiting,

severe headaches• Other sources of concern

Eg. drug or alcohol intoxication, shock, suspected non-accidental injury, meningism, cerebrospinal fluid leak

Observation in ward

Document GCS; pupil size and reactivity; limb movements; RR, PR, BP, T, SpO2Perform and record observations on a half-hourly basis until GCS equal to 15 has been achieved. The minimum frequency of observations for patients with GCS equal to 15 should be as follows, starting after the initial assessment in the emergency department:•Half-hourly for 2 hours.•Then 1-hourly for 4 hours.•Then 2-hourly thereafter.

Extradural Haematoma• A neurosurgical emergency • Almost always associated with skull fracture • Tearing of the meningeal artery and the haematoma accumulates

in the space between the bone and the dura• Most common site ; temporal ( pterion)• Classical presentation ; Initial LOC may be there (cerebral

concussion) at the time of injury• followed by lucid interval ( all vital signs are normal, GCS is 15)

(=compensatory phase)• subsequent rapid deterioration of conscious level due to enlarging

haematoma causing brain herniation may be associated with contralateral hemiplegia and ipsilateral pupil dilatation

Hutchinson’s pupil pupil on the side of

an intracranial mass lesion is dilated and unreactive to light, due to compression of the oculomotor nerve on that side.

• Early recognition and treatment >> likely full recovery

• Delay in d/x >> death d/t secondary brain injury• CT scan ; lentiform, hyperdense lesion, associated

mass effect, with or without MLS• Treatment ; immediate surgical evacuation via a

craniotomy

Acute Subdural Haematoma• Blood accumulates in the space between the dura and

the arachnoid • Disruption of a cortical vessel or brain laceration • impaired conscious level from time of injury, but can

further deteriorate as the haematoma expands• CT scan: hyperdense lesion, diffuse and concave shape • T/x ; evacuation via a craniotomy• Small haematomas with little mass effect ; conservative

Subarachnoid Haemorrrhage • Traumatic SAH > managed conservatively

Cerebral contusions• brain being damaged by impacting against the skull either at

the point of impact (coup) or on the other side of the head(counter-coup)

• or as the brain slides forwards and backwards over the ridged cranial fossa floor

• CT scan; Heterogenous with mixed areas of high and low density, may be an associated mass effect

• Rarely require immediate surgical treatment • Must be admitted for observation > as the lesions tend to

mature and expand for 48 to 72 hours PT • delayed evacuation to reduce the mass effect (small

proportion)

When to re-evaluate?• Development of agitation or abnormal behaviour.• A sustained (for at least 30 minutes) drop of 1 point in GCS

score (Esp . the motor response) • Any drop of 3 or more points in the eye-opening or verbal

response scores of the GCS, or 2 or more points in the motor response score.

• Development of severe or increasing headache or persisting vomiting.

• New or evolving neurological symptoms or signs such as pupil inequality or asymmetry of limb or facial movement

Role of A repeat Brain CT Scan

• If the first CT demonstrates an intracranial lesion then apply the BTF criteria for surgical intervention

• In no surgical intervention is indicated, repeat CT should be performed between 6 to 12 hours after initial trauma – regardless of the patient’s clinical exam.

• If on repeat CT > stable or improved > no further imaging is required, and can follow clinical exam.

• If there is deterioration > BTF criteria for surgical intervention• 2 sequential studies stable > > no further imaging is required,

and can follow clinical exam.

When to go conservative?• Patients with good GCS

-showing progressive improvement-static with normal coma score

• Patients with haematoma with poor GCS-ICP shows normal pressure

• Multiple small contusions or haematoma -none of them individually producing mass effect

• Patients with haematoma in -Brain death -Impending brain death

Indications for surgery in head injury

• In acute head injury1) Large intracranial haematoma producing mass effect and raised ICP -patient is deteriorating etc 2) Compound head injury -scalp laceration with comminuted # , or CSF leak -Surgery for foreign body eg bullet etc -Profuse CSF leak not controlled on conservative management in 2-3 weeks time

• Chronic head injury eg.CSF fistulae, hydrocephalus,abscess etc

Surgical management of Head Injury

• Early Evacuation of focal haematomas; EDH, ASDH• CSF drainage via ventriculostomy • Delayed evacuation of swelling contusion • Decompressive craniectomy

- to control the ICP in pt without a focal Intracerebral haematoma in whom the ICP is refractory to maximal medical therapy

Craniotomy

Raising the skin flap & making the Burr – holes prior to doing a Craniotomy

Medical Management ofSevere Head Injury

• Aim : control of ICP ( Normal ICP is 8-12mmHg) • A sustained ICP of > 20mmHg ; poor outcome1)Positioning2)Avoid obstruction of venous drainage from head3)Sedation +/- muscle relaxant4)Normocapnia 4.5-5.0 kPa5)Diuretics : Furosemide, mannitol 6)Seizure control7)Normothermia8)Sodium Balance9)Barbiturates

•Head up 30’ if spinal clearance allows > venous return•Ensure that Cervical immobilisation collar does not obstruct venous return from the head •A definitive airway •Hypoxia and hypercapnia >> increase brain ischaemia and secondary brain injury•Once intubated ;normocapnia is maintained (PaCO2 4.5-5 kPa)•The cerebral vasculature is reactive to CO2 levels. A rise in PaCO2 in + high ICP >> generalised cerebral vasodilatation >> increased IC Blood volume >> further raise ICP >> reduced cerebral perfusion•Cerebral perfusion pressure should be maintained at >65mmHg

ICP monitoring• An ICP monitor may be parenchymal or ventricular

• Sedation , with or without muscle relaxants • Use of diuretics – Eg Mannitol and furosemide will

temporarily reduce the cerebral swelling and ICP• Thermoregulation ; Pyrexia increases brain metabolic

rate. Active cooling is used in some centres. • Barbiturates ; Eg Thiopentone reduces Brain Metabolic

rate and helps reduce ICP. • Maintaining fluid and electrolyte balance – susceptible

to disturbances of Na haemostasis eg Diabetes insipidus and SIADH)

• Seizure control ; Prophylactic anticonvulsants

Role of Anti-epileptics in TBI

• Had a seizure after a head injury > continued for 6 months to 1 year

• Phenytoin 15-18 mg/kg IV bolus followed by 200 mg IV q12h)

• Prophylactic anticonvulsants to all patients with significant head injury for at least 1st few days after injury

• If seizures are not evident in the acute phase, anticonvulsants are discontinued in 1 week

Role of Antibiotics in TBI

• Broad-spectrum antibiotics ; A cephalosporin or Augmentin is recommended.

• Indications ; -post-operatively -Skull base fracture with CSF leak -Pneumocephalus

• Usually IV Ceftriaxone 2g BD(anti-meningitis dose) or just 1g BD for 1 week

The stress of ICP

• Prophylaxis with histamine blockers and/or antacids should be implemented.

• stress of head injury ; leads to increased energy consumption by the injured patient's body

• thus, Enteral nutrition is employed if no contraindications exist, in the 1st few days; whereas, parenteral nutrition is reserved for patients with associated abdominal injuries

Complications• Insomnia• Cognitive decline• Posttraumatic headache• Posttraumatic depression• Posttraumatic seizures• Hydrocephalus• Deep vein thrombosis• Spasticity• Gastrointestinal complications:cushing’s ulcers.• Gait abnormalities

Discharge criteria

- GCS 15/15 with no focal neurological deficit- patient must be accompanied by a responsible adult and should not be under the influence of alcohol or other drugs -Verbal and written head injury advice must be given to both patient and their accompanying adult >> ssx that warrant TCA STAT to ED Eg Persistent or worsening headache despite analgesia, persistent vomiting, drowsiness, visual disturbance, development of weakness or numbness in the limbs

References• Medscape references on Traumatic Brain Injury, penetrating head trauma etc • Bailey and Love’s Short Practice of Surgery 25th edition • NICE guidelines

Head Injury ; Assessment and Early Management Recommendations (January 2014)

• Manual of Definitive Surgical Trauma Care by Kenneth D.Boffard , Publication of International Association for the Surgery of Trauma and Surgical Intensive Care

• Handbook of Trauma Care 6th edition ; The Liverpool Hospital Trauma Manual • Guidelines for the management of Severe Traumatic Brain Injury 3rd edition,

Journal of Neurotrauma by Brain Trauma Foundation, US • Guidelines for the Surgical Management of Traumatic Brain Injury , by BTF.

2006