Head Injury / Extradural Hematoma

Question 1

CT features

Answer 1

• Biconvex shape, hyperdense
• Midline shift
• Compression on the ventricles

Question 2

When to consider CT brain for trauma?

Answer 2

High Risk Criteria
• GCS < 15 at 2h post-injury
• Suspected open or depressed skull fracture
• Any sign of basilar skull fracture
o Hemotympanum
o Raccoon Eyes
o Battle’s Sign
o CSF oto-/rhinorrhea
• ≥ 2 episodes of vomiting
• Age ≥ 65
• Any head injury in anticoagulated patient

Medium Risk Criteria
• Retrograde Amnesia to the Event ≥ 30 minutes
• “Dangerous” Mechanism
o Pedestrian struck by motor vehicle
o Occupant ejected from motor vehicle
o Fall from > 3 feet or > 5 stairs

Question 3

Normal value of ICP?

Answer 3

7 to 15 mmHg (supine)

Question 4

Ways to measure?

Answer 4

Invasive:
Lumbar CSF pressure
Intracranial transducers

Non invasive:
Tympanic membrane
displacement
Transcranial Doppler

Question 5

What is the danger of lumbar puncture in increased ICP?

Answer 5

Herniation and coning

Question 6

What is the Cushing reflex?

Answer 6

Physiologic nervous system response (mixed vagal and sympathetic stimulation) to an elevated ICP that results in
Cushing’s triad. It leads to hypertension, which ensures an adequate CPP. There is also a resultant bradycardia.

Question 7

Pathophysiology of increased ICP?

Answer 7

(Monro - Kellie doctrine / hypothesis)
• The skull is fixed box containing 3 components
o Brain (80%), blood (10%), CSF (10%)
• ICP/volume relationship is governed by these 3 components
• Increase in volume in one component may result in compensatory decrease in the volume of another
component in order to prevent rise in ICP (compensation)
• However, once the ICP has reached around 25 mmHg, small increases in brain volume can lead to marked
elevations in ICP; this is due to failure of intracranial compliance (decompensation) leading to brain herniation

Question 8

Lucid interval?

Answer 8

A temporary improvement in a patient condition after traumatic brain injury after which the condition deteriorates with
rapid decline of consciousness
During this period, blood accumulates in the extradural space leading to an increase in ICP leading to
cerebral edema

Question 9

CPP =

Answer 9

CPP = Mean arterial pressure - Intra cranial pressure
MAP = Diastolic +
1/3(Systolic - Diastolic pressure)

MAP auto-regulation range is between 50 - 150 mmHg to maintain a constant cerebral blood flow in cases of traumatic
brain injury, this will be disruption of MAP autoregulation →cerebral ischemia

Question 10

Conditions where ICP-monitoring is used.

Answer 10

• Traumatic head injury
• Intracerebral hemorrhage
• Subarachnoid hemorrhage
• Hydrocephalus
• Malignant infarction
• Cerebral edema
• CNS infections
• Hepatic encephalopathy

Question 11

Clinical picture of increased ICP?

Answer 11

• Headache
• Nausea, vomiting
• Papilledema
• Fall in GCS
o Pressure symptoms (hematoma)
o Ischemia (loss of autoregulation of MAP)
• Dilated pupil (oculomotor nerve palsy)
• Defect in lateral gaze (abducent nerve palsy)
• Cushing’s triad (not to be confused with Cushing
reflex)
o Increased systolic blood pressure &
widened pulse pressure
o Bradycardia
o Irregular respiratory pattern

Question 12

Management?

Answer 12

• ABC
• Intubation

Question 13

Indications for intubation?

Answer 13

• GCS ≤ 8
• Risk of raised ICP due to agitation (i.e. sedation required)
• Inability to control/protect the airway or loss of protective laryngeal reflexes. A fall of 2 or more points in the
motor component of the GCS
• In order to optimize oxygenation and ventilation
• Seizures
• Bleeding into mouth/airway
• Bilateral fractured mandible, severe facial injuries

Question 14

Management of raised ICP?

Answer 14

Improving venous drainage from the brain
• Elevation of the head of the bed to 30
• Good neck alignment – head in the neutral position
• Ensuring ties holding the endotracheal tube in place do not compress the neck veins. Alternatively tape the tube
using ‘trouser-legs’.
• Where possible immobilize the patient’s cervical spine with sandbags and tape rather than restrictive neck
collars

Reducing cerebral edema
• Use mannitol (an osmotic diuretic) 0.5-1g/kg (= 5-10ml/kg of 10% or 2.5-5ml/kg of 20% mannitol). Some unit
use small aliquots of hypertonic saline as an alternative
• Use frusemide (a loop diuretic) 0.5-1mg/kg
• Maintain serum Na+ in the range 140-145mmol/l

Reduction of the cerebral metabolic rate for oxygen:
• Close temperature regulation. Avoid hyperthermia, but do not actively induce hypothermia.
• Use of sedation and anaesthetic drugs. Ensure that the patient is appropriately sedated and has received
adequate analgesia.
• If the patient has a witnessed seizure loading with an anticonvulsant, usually phenytoin 18mg/kg, should be
considered.
• In cases of intractable raised ICP, a thiopentone infusion can be used to reduce the cerebral metabolic rate to a
basal level. This is identified on EEG monitoring as ‘burst suppression’.

Reducing intracranial blood volume
• Hyperventilation can be used to reduce the PaCO2 as a temporary measure, but cerebral ischemia may result if
this is prolonged.
• The final resort if ICP remains raised is to perform a decompressive craniectomy.

Reducing CSF volume
In a neurosurgical centre, use of an external ventricular drain (EVD) allows drainage of CSF to relieve raised ICP