Approach to head injury

Approach to Head Trauma

Dr Abdulaziz Alrabiah, MD

Overview

• Definition: An insult to the brain from an external mechanical force, potentially leading to an altered level of consciousness and permanent or temporary impairment of cognitive, physical, and psychosocial functions.
• Accounts for $>30\%$ of trauma deaths.
• Leading cause of disability under the age of 40 years.
• Bimodal distribution:
  • Young adult males (Risk takers – occupation).
  • Elderly (Risk of fall).

Causes

• Mechanisms: Blunt or penetrating.
• Common Etiologies:
  • Falls (Most common cause).
  • MVC (Cause of most TBI deaths).
  • Violence and assaults (Increase nowadays).
  • Industrial accidents.
  • Sport.
• Special Considerations:
  • Non-accidental Injury (NAI) in children = Abuse.
  • Elder abuse (دور الرعاية).
  • Domestic violence (Couples and always make sure that the wife is not Pregnant).

Classification of Brain Injury

Primary Brain Injury

• Occurs at the time of the traumatic incident $\to$ direct cellular and tissue injury.
• Note: Cannot be prevented post-event (“I can’t prevent it”).

Secondary Brain Injury (can be prevented)

• Occurs days after the insult if the primary injury is not treated well.
• Further cellular damage.
• Major determinant of neurological outcome.

Grading of Head Injury

• Mild
  • GCS 14-15.
  • Brief LOC, nausea, cognitive, behavioural, and emotional disturbance.
• Moderate
  • GCS 9-13 after non-surgical resuscitation.
• Severe
  • GCS < 8 after non-surgical resuscitation.

Glasgow Coma Scale (GCS)

Glasgow Coma Score
Eye Opening (E)	Verbal Response (V)	Motor Response (M)
4 = Spontaneous	5 = Normal conversation	6 = Normal
3 = To voice	4 = Disoriented conversation	5 = Localizes to pain
2 = To pain	3 = Words, but not coherent	4 = Withdraws to pain
1 = None	2 = No words… only sounds	3 = Decorticate posture
	1 = None	2 = Decerebrate
		1 = None
		Total = E + V + M

Indication for Imaging (CT/MRI)

Definite Indications

(Examples)

• LOC for > 5 minutes.
• Focal neurological findings.
• Seizure.
• Failure of mental status to improve over time in an alcohol-intoxicated patient.
• Penetrating skull injuries.
• Signs of a basal or depressed skull fracture.
• Coagulopathy.
• Previous shunt-treated hydrocephalus.
• Infants and children.
• Age > 60.

(Note: “Names only”)

New Orleans Criteria

• Headache.
• Vomiting.
• Age > 60 yrs.
• Drug or alcohol intoxication.
• Deficits in Short Term Memory (STM).
• Evidence of trauma above the clavicles.

Canadian CT Head Rules

High Risk Features (for neurological intervention)

• GCS < 15 for 2 hours post injury.
• Suspected open or depressed skull fracture.
• More than 2 episodes of vomiting.
• Physical evidence of basal skull fracture.
• Age > 65.
• Coagulopathy.

Medium Risk Features (for brain injury detection)

• Antero-grade amnesia for more than 30 min prior to injury.
• Dangerous mechanism:
  • Pedestrian vs motor vehicle.
  • Ejection from vehicle.
  • Fall from > 3 feet.

Specific Types of TBI

Skull Fracture

• From contact force.
• Usually associated with a brief loss of consciousness.
• Linear: Lateral convexities of skull.
• Depressed: Blunt force from an object with a small surface area (e.g., hammer).
• Compound fracture: Open fracture.
• Basal Skull Fracture (BOS): Severe blunt trauma to forehead or occiput.

Diagram illustrating types of skull fractures.

Subdural Haematoma (SDH)

• Tearing of bridging veins.
• Common in age $>65$ y/o (mild trauma causes injury because brain shrinkage makes veins fragile).
• Doesn’t expand to contralateral hemisphere.
• Often associated with cerebral contusion underneath.
• Appearance: Crescent shape (Moon Shape) + shifting of midline.

Axial CT scan showing a subdural hematoma as a crescent-shaped hyperdense collection.

Epidural Hematoma (EDH)

• Usually from Middle Meningeal Artery tear with associated skull fracture.
• Most are temporal or parietal, but can occur in frontal and occipital lobes (rare in posterior fossa).
• Common in young adults.
• Appearance: Classic lenticular shape.
• Clinical Feature: Lucid Interval (Behaves totally normal then sudden deterioration/arrest).
• Risk: Brain herniation from Foramen magnum due to high pressure.

Axial CT scan showing a large, hyperdense, biconvex (lenticular) epidural hematoma.

Subarachnoid Haematoma (SAH)

• Does not produce a haematoma or mass effect.
• May cause post-traumatic vasospasm.
• Appearance: Star sign.
• Management: Conservative treatment.

Axial CT scan showing subarachnoid haematoma (Star sign).

---

Cerebral Contusions

• Definition: Bruising / Swelling.
• Heterogenous lesions comprising of punctate haemorrhage, oedema, and necrosis.
• Do evolve over time (may not be visible on first CT) $\to$ Normal.
• Can cause significant mass effect with herniation.
• May cause headache $\to$ elevated ICP and coma.

---

Diffuse Axonal Injury (DAI)

• Mechanism: Injury at the level of myelin sheath/axons.
• Lacerations or punctate contusions at the interface between grey and white matter.
• Caused by a rotational vector of injury.
• Common cause of persistent vegetative state or prolonged coma.
• Diagnosis: Often a diagnosis of exclusion (“Rule out everything”) or pathological diagnosis by sample.

Management of TBI

Initial Resuscitation

• Seek and Treat ABC.
• Airway: Intubation if GCS 8 or below.
• Breathing: Treat hypoxia (Target $O_2$ sat $>95\%$).
• Circulation: Treat hypotension (Fluid, blood, vasopressor).
  • Target: SBP $>90$ mmHg, MAP $>65$ mmHg.
  • Vasopressors mentioned:
    • Adrenalin / Nor-adrenalin
    • Epinephrin / Dopamin

Measures to Decrease Secondary Brain Injury

• Positioning: Head elevation $>30$ degrees (gravity helps decrease fluid/ICP).
• Sedation and analgesia.
• Paralysis: If intubated.
• Ventilation: Maintain ${\text{PaCO}}_2$ 30-35 mmHg.
  • Causes vasoconstriction $\to$ $\uparrow$ Cerebral Blood Flow (Note: text says $\uparrow$ flow/ICP, but physiology suggests constriction $\downarrow$ CBF/ICP. Preserved original implied logic of “constriction”).
• Osmotherapy:
  • Mannitol: 1 gm/Kg (Diuretic).
  • Hypertonic saline: 3%, 3ml/kg over 30 min.
• Surgical: De-compressive craniotomy (Remove bone flap until recovery, 6 months - 1 year).
• General Measures:
  • Avoid hyperthermia.
  • Seizure prophylaxis (Note: no evidence of benefit).
  • DVT prophylaxis (TEDS, heparin/clexane within 2-3 days of injury).

---

Contact: aalrabiah@ksu.edu.sa