A 45-year-old who lost consciousness following head trauma

• Coup injury is a direct injury to the brain below the skull at the point of impact.
• Contrecoup is an injury to the brain on the side opposite the site of impact, as it is forced against the opposite skull.

Coup injury is caused by a stationary head hit by a moving object.

Contrecoup injury is caused by a stationary object hit by a moving head

• A concussion is a term used for minimal head injury where there is transient confusion or altered mental status following trauma. Symptoms may include headache, dizziness, confusion, personality changes, and irritability, and may have problems with memory, balance, coordination, and/or concentration.

A concussion may range from altered mental status to loss of consciousness. It is thought to be due to impairment of the Reticular Activating System (RAS) caused by shear forces

• A lucid interval is a period of regained consciousness between the first loss of consciousness (from disruption of the RAS) and the second loss of consciousness (from the expanding hematoma and mass effect)

May last minutes to hours and is classically seen in epidural hematoma.

• Eye signs: Fixed dilated pupil, Papilloedema, Blurry vision, Abducens Nerve Palsy
• Headache
• Projectile Vomiting
• Seizures
• Altered Mental Status (drowsiness → coma)
• Bulging fontanelles in infants

• Hypertension (wide pulse pressure)
• Tachypnoea (irregular breathing)
• Bradycardia

AKA cushing reflex. Blood pressure increases in the setting of raised ICP to maintain Cerebral Perfusion Pressure (CPP = MAP – ICP). Increased pressure results in negative feedback at the carotid sinus causing bradycardia. Raised ICP also impairs the respiratory centres in the medulla causing irregular respiration

• Arterial Pressure
• Intracranial pressure which constitutes 3 components: brain tissue, cerebrospinal fluid, and blood.

Monroe-Kellie Doctrine: Volume within the skull remains constant

The brain is enclosed within the rigid bony cranium. In order to maintain ICP, an increase in one of the factors listed above must result in a decrease in the volume of the other two components.

Remember CPP = MAP – ICP

For example, if there is bleeding within the skull, ICP is raised causing a decrease in CPP. In order to compensate the body raises Mean Arterial Pressure to maintain CPP.

• CO2

Lowering PaCO2 by mild hyperventilation can help to lower ICP

• GCS is calculated from three components: eye opening, verbal response, and motor response. It is frequently assessed and reassessed to determine if the patient’s Traumatic Brain Injury is worsening.

• The score is graded as follows:
  • 13-15: Mild Traumatic Brain Injury
  • 9-13: Moderate Traumatic Brain Injury
  • ≤ 8: Severe Traumatic Brain Injury

• GCS 7
  • Motor 4 – withdraws from pain
  • Verbal 2 – Incomprehensible (moaning)
  • Eyes 1 – no eye opening
  A patients with a GCS of ≤ 8 is considered to be in a coma and their airway needs to be secured via orotracheal intubation

• Alcohol intoxication
• Drug intoxication
• Sedatives
• Severe hypoxia
• Shock
• Severe hypothermia

• A blown pupil refers to a fixed and dilated pupil resulting from the compression of the oculomotor nerve (CN 3) by the herniated uncus of the temporal lobe

This patient has a blown pupil on the right.

The herniating uncus also compresses the ipsilateral cerebral peduncle resulting, in injuring the ipsilateral corticospinal tract and leading to contralateral hemiparesis.

• Lateralization refers to the localization of neurological signs and symptoms to one side of the brain. The left and right hemispheres control certain functions of the body. In brain injury, specific regions of one hemisphere can be affected resulting in characteristic signs and symptoms that manifest predominantly on one side of the body.
• Localizing signs are neurological signs and symptoms that can help determine the location of brain injury within the cerebral hemispheres. These signs include motor deficits (hemiparesis, hemiplegia), asymmetric reflexes, sensory deficits (numbness, tingling), visual field defects (hemianopsia), and speech/language deficits (aphasia, dysphasia)
• Paralysis generally occurs CONTRALATERAL to the lesion
• An abnormal pupillary finding e.g. blown pupil occurs IPSILATERAL to the lesion

Dot marks the spot!

• The lesion localizes to the right

He has left hemiparesis and a blown pupil on the right

• Kernohan-Woltman Notch Phenomenon (KWNP) – occurs in 1 in 5 cases
• This is a false localizing sign whereby extensive midline shift caused by mass effect causes the contralateral cerebral peduncle to be displaced and compressed against the contralateral tentorial incisura (Kernohan notch) resulting in paralysis IPSILATERAL to the lesion

The pupil is a more reliable lateralizing sign. Dot marks the spot!

• Decorticate posturing – seen in lesions above the red nucleus
  • Disinhibition of the rubrospinal tract causes upper limb flexion
  • The vestibulospinal/reticulospinal tracts override the disrupted corticospinal tract causing lower body extension

Better prognosis than decerebrate posturing

• Decerebrate posturing – seen in lesions below the red nucleus
  • Both the rubrospinal and corticospinal tracts are lostVestibulospinal/reticulospinal tract override causing everything to be in extension
  Worse prognosis than decorticate posturing

• Rhinorrhoea
• Battle’s sign (retroauricular ecchymosis)
• Racoon eyes (bilateral periorbital ecchymosis)
• Otorrhoea
• Hemotympanum
• Hearing loss

• Scalp lacerations
• Palpate for fractures (not all fractures occur with scalp lacerations)
• Primitive reflexes e.g. Babinski reflex

• Severe Traumatic Brain Injury as evidenced by GCS of 7 (eyes 1, verbal 2, motor 4)
• Likely Right-sided Epidural Hematoma due to evidence of a right temporal bone fracture (hemotympanum) and blown pupil on the right. He also displays the classic sequence for an EDH: consciousness → brief lucid interval → progression to coma
• He also has signs of raised intracranial pressure and uncal herniation with a dilated non-responsive right pupil and left-sided hemiplegia

Epidural hematoma commonly occurs from rupture of the middle meningeal artery following a temporal bone fracture

• A TBI is a disruption of brain function with any of the following criteria met:
  • A period of loss of consciousness
  • Loss of memory for events immediately before or after the accident
  • Altered mental status at the time of accident
  • Focal neurological deficits

• Maintain MAP >90mmHg to allow for CPP of > 70 mmHg in the presence of slightly raised ICP (> 20 mmHg)
• Maintain SpO2 > 95%
• Maintain PaCO2 4.5-5.0 kPa (34 – 48 mmHg) in intubated patients
• Maintain Hb > 7g/dL
• Maintain normothermia
• Maintain normoglycemia

• Manage ABCs as per ATLS guidelines
  • GCS ≤ 8 (as in this patient) requires orotracheal intubation to protect the airway
  • Ensure optimal oxygenation and ventilation. Get Arterial Blood Gas.
  • Document neurologic exam before paralysis and intubation (during the secondary survey). This information will become useful once the patient is sedated/paralyzed
  • Intubation and paralysis can help facilitate the management of ICP
  • Obtain non-contrast head CT
  • Investigate for coagulopathy and correct
  • Other trauma imaging (depending on mechanism) and labs (CBC, BMP, GXM, Blood Alcohol Level, Urine toxicology)
  • Anticipate evacuation
  Since this patient is unconscious physical exam might be unreliable to rule out injuries to the chest, abdomen, and pelvis. Hypoxia and Hypotension are independent risk factors for mortality in head injury. Succinylcholine and Ketamine can increase ICP and are relatively contraindicated in the setting of TBI. Rocuronium and Etomidate/Sodium Thiopental are preferable options. Patients with TBI are at risk of DIC and should have their coagulation and platelets monitored

• Loss of consciousness at injury
• Neurological deficit (GCS anything less than 15)
• Altered mental status or confusion
• Moderate to severe mechanism
• Suspected skull fracture on palpation
• Suspected base of skull fracture

Look for skull fractures, intracranial bleed, contusion, and axonal injury

Indications for head CT are much stricter in children since they have a greater risk of malignancy from the ionizing radiation from a CT scan compared to adults. Relative indications for head CT in children include scalp hematoma, severe mechanism of injury, history of vomiting, severe headache, and if the parent reports that the child is not acting properly.

• Elevate the head of the bed to 30-45 degrees (to improve venous drainage from the head)
• Reduce cerebral edema by using Mannitol or Hypertonic saline
• Sedation, analgesia, and close temperature regulation to reduce Cerebral Metabolic Rate of Oxygen (CMRO2)
• Anticonvulsants for seizure prophylaxis
• Temporary hyperventilation to reduce intracranial blood volume
• Barbiturate coma
• Decompressive craniotomy
• External ventricular drains (EVD) to drain CSF

If a cervical collar is in place it can be loosened if it restricts venous outflow

Hyperthermia should also be treated if it is present. Some sources even advocate for therapeutic hypothermia.

• Hyperventilation reduces PaCO2 to cause cerebral vasoconstriction which in turn reduces cerebral blood flow

Mild hyperventilation can be used temporarily before ICP monitoring in patients with CT findings/clinical signs of raised ICP

PaCO2 should be kept between 30-35 mmHg for hyperventilation. Reducing PaCO2 to lower than 30mmHg can severely decrease cerebral blood flow.

Hyperventilation can be discontinued once other methods of ICP control are started.

• Mannitol is an osmotic diuretic
• It increases the tonicity of extracellular space → water shifts from the intracellular space (brain parenchyma) to extracellular space

Mannitol should not be used in patients with hypotension or hypovolemia due to its volume-depleting effects

It should also be avoided with intracranial aneurysm and arteriovenous malformations until the cranium is opened because diuresis can expand the hematoma as normal brain tissue volume decreases

• Severe TBI with abnormal head CT (GCS 3-8)
• Severe TBI with normal head CT but with any two of these:
  • Hypotension
  • Posturing
  • Age ≥ 40
• In patients with suspicion of raised ICP when neurological exam cannot be appropriately assessed due to sedation or anesthesia

Normal ICP is 5-15 mmHg. Treatment of raised ICP is indicated for pressure > 20mmHg in adults (but lower levels for children).

• Ventriculostomy tube/EVD that can be used to drain CSF when ICP becomes high

EVD is the gold standard for ICP monitoring. Other methods include a subarachnoid probe, intraparenchymal probe, transcranial doppler, lumbar CSF pressure, and tympanic membrane displacement.

Clinical signs can also be used to identify and monitor raised ICP and these include headache, nausea and projectile vomiting, focal weakness, asymmetric pupils, Cushing’s reflex, confusion, and loss of consciousness

• There is no role

Corticosteroids are used to treat cerebral edema caused by inflammatory processes and tumors.

The mechanism of cerebral edema in trauma and inflammation are fundamentally different. In inflammation and tumors there is cytotoxic edema and this responds to corticosteroids. In trauma there is vasogenic edema and this is not responsive to corticosteroids.

• Midline shift > 10mm
• Hematoma thickness > 5mm
• Intracranial pressure > 20mmHg
• Chronic subdural hematoma

Craniotomy involves removing a bone (skull) flap to evacuate a hematoma. The bone flap is returned after evacuation.

Smaller hematomas can be observed with serial head CT scans and can be managed conservatively

• Raised ICP cannot be managed conservatively

Craniectomy involves removing a bone (skull) flap and closing the skin without replacing the bone flap. The bone flap is stored for re-implantation at a future date. Bone is usually removed over the temporal fossa or bifrontal (Kjellberg)

• New neurological signs e.g. pupillary dilation, hemiparesis
• Continued vomiting
• Worsening headache
• Loss of ≥ 2 points on GCS
• Any other signs of raised ICP

• Hypotension (SBP < 90)
• Hypoxemia
• Hypercarbia
• Raised ICP > 20 mmHg despite hyperventilaiton
• Advanced age
• Midline deviation

Brain death is irreversible cessation of entire brain function including the brainstem.

• GCS of 3
• Euthermic (.32.2 C)
• PaO2 90 mmHg
• SBP > 100mmHg
• The patient should not be sedated or paralyzed (serum or urine toxicology screen is required)

• Absence of brainstem reflexes (corneal, gag, oculocephalic, and oculovestibular)
• No response to deep central pain
• Two physicans agree that the patient is brain dead

If these conditions are met an apnea test is performed. The patient is disconnected form the ventilator and observed for respiratory effort. If there is no evidence of spontaneous respiration with a PaCO2 > 60mmHg and other criteria are met, the patient meets the criteria for brain death.