Head and Brain Trauma

Overview

Head and Brain Trauma encompasses injury to the scalp, skull, or brain tissue (Traumatic Brain Injury, TBI) resulting from external mechanical forces.

Classification:

• Primary Injury: Damage occurring at the moment of impact (e.g., contusions, lacerations, diffuse axonal injury, intracranial hematomas).
• Secondary Injury: Downstream cellular and physiological cascade (hypoxia, hypotension, cerebral edema, elevated intracranial pressure [ICP], ischemia) progressing over hours-to-days.
• Severity (by GCS)
  • Severe (GCS 3–8)
  • Moderate (GCS 9–12)
  • Mild (GCS 13–15).

Approach

Step 1: Primary Survey & Immediate Stabilization (ATLS ABCDE)

• Airway with Cervical Spine Motion Restriction: Secure airway if GCS <= 8 or patient unable to protect airway.
• Breathing: Maintain normocapnia (PaCO2 35–45 mmHg; ETCO2 35–40 mmHg). Avoid routine hyperventilation.
• Circulation: Resuscitate aggressively with isotonic crystalloids (0.9% Normal Saline or Plasmalyte; avoid hypotonic fluids like 0.45% NaCl or D5W which worsen cerebral edema). Target SBP >= 100–110 mmHg.
• Disability: Assess GCS, pupil size and reactivity, and focal neurological signs.
• Exposure: Log roll to examine scalp/spine; maintain normothermia.

Step 2: Recognize Signs of Impending Brain Herniation / Severe Elevated ICP

• Cushing’s Triad: Severe Hypertension (widened pulse pressure) + Bradycardia + Irregular Respirations (Cheyne-Stokes).
• Pupillary Signs: Anisocoria (unilaterally dilated, sluggish/fixed pupil) $\rightarrow$ Uncal herniation compressing ipsilateral CN III.
• Posturing: Decorticate (flexor) or Decerebrate (extensor) posturing.

Step 3: Branching Logic & Imaging Decisions (Canadian CT Head Rule for Mild TBI GCS 13–15)

• High Risk for Neurosurgical Intervention (CT Mandatory):
  • GCS < 15 at 2 hours post-injury.
  • Suspected open or depressed skull fracture.
  • Any sign of basal skull fracture (hemotympanum, “racoon eyes”, Battle’s sign, CSF otorrhea/rhinorrhea).
  • = 2 episodes of vomiting.
  • Age >= 65 years.
• Medium Risk (CT Recommended): Amnesia before impact > 30 minutes, dangerous mechanism (pedestrian struck, ejected occupant, fall > 3 feet or 5 stairs).

Differential Diagnosis

Extra-Axial Intracranial Hemorrhages:

• Epidural Hematoma (EDH):
  • Mechanism: Tear of Middle Meningeal Artery associated with temporal bone fracture.
  • Distinguishing features: Classic “Lucid Interval” (brief loss of consciousness $\rightarrow$ transient clarity $\rightarrow$ rapid neurological decline); Biconvex / Lens-shaped hyperdensity on CT that does NOT cross suture lines.
• Subdural Hematoma (SDH):
  • Mechanism: Tear of Bridging Veins (common in elderly, alcoholics, or anticoagulated patients).
  • Distinguishing features: Crescent-shaped hyperdensity on CT that crosses suture lines; can be acute (hyperdense), subacute (isodense), or chronic (hypodense).
• Subarachnoid Hemorrhage (Traumatic SAH):
  • Mechanism: Disruption of superficial cortical vessels; most common intracranial lesion in TBI.
  • Distinguishing features: Blood tracking within sulci and basal cisterns; thunderclap headache, photophobia, meningismus.

Intra-Axial Injuries:

• Cerebral Contusion & Intraparenchymal Hemorrhage (IPH):
  • Mechanism: Coup (site of impact) or contrecoup (opposite site) impact against bony skull protuberances (frontal/temporal poles).
  • Distinguishing features: “Punctate / Salt and Pepper” hyperdensities on CT; high risk of delayed expansion within 24–48 hours.
• Diffuse Axonal Injury (DAI):
  • Mechanism: High-speed deceleration / rotational shearing forces (e.g., high-speed motor vehicle collision).
  • Distinguishing features: Severe profound coma out of proportion to CT findings; microscopic punctate hemorrhages at grey-white matter junction, corpus callosum, and brainstem (best seen on MRI DWI/FLAIR).

Skull Fractures:

• Basal Skull Fracture:
  • Distinguishing features: Battle’s sign (mastoid ecchymosis), Raccoon eyes (periorbital ecchymosis), CSF rhinorrhea/otorrhea, CN VII/VIII palsy. STRICTLY CONTRAINDICATED: Nasogastric tube insertion (risk of intracranial entry; use orogastric tube instead).

Investigations

First-Line / Bedside Diagnostics:

• Serial Glasgow Coma Scale (GCS) & Pupillary Exam: Repeat every 15–30 minutes in acute stages.
• Point-of-Care Blood Glucose & ABG/VBG: Exclude hypoglycemia/hypoxia/hypercapnia as primary or contributing causes of altered mental status.
• Coagulation Profile (INR, APPT, Fibrinogen, Platelets): Critical in patients on anticoagulants/antiplatelets (e.g., Warfarin, DOACs).
• Serum Electrolytes (Na+, K+): Baseline before hyperosmolar therapy; check for SIADH or CSW.

Targeted / Diagnostic Imaging Strategy:

• Non-Contrast CT Head (Gold Standard): Immediate modality of choice for acute head trauma. Evaluates hemorrhage, mass effect, midline shift (> 5 mm indicates significant risk), ventricular effacement, and skull fractures.
• CT Angiography (CTA) Head & Neck: Indicated if blunt cerebrovascular injury (BCVI) is suspected (e.g., neck trauma, transverse process fractures, basilar skull fractures).
• MRI Brain (Non-emergent / Secondary): Superior for identifying Diffuse Axonal Injury (DAI), brainstem lesions, and unexplained persistent neurological deficits when CT is normal.

Critical Management

Emergency Management of Elevated ICP / Impending Herniation:

• Positioning: Elevate head of bed 30 degrees; keep head/neck in midline position (prevents jugular venous compression).
• Hyperosmolar Therapy:
  • 3% Hypertonic Saline: 250 mL IV bolus over 15–20 minutes (or 2 mL/kg). Target serum Na+ 145–155 mmol/L.
  • Mannitol 20%: 0.5–1.0 g/kg IV bolus over 15–20 minutes (avoid if SBP < 90 mmHg / hypotensive).
• Controlled Hyperventilation (Emergency Bridging ONLY): Target PaCO2 30–35 mmHg only during active herniation crises; stop once hyperosmolar therapy takes effect.

Hemodynamic & Physiological Targets (Brain Trauma Foundation Guidelines):

• Blood Pressure: Target SBP >= 100 mmHg (ages 50–69) or >= 110 mmHg (ages 15–49 or >= 70).
• Intracranial Pressure (ICP): Keep ICP < 22 mmHg.
• Cerebral Perfusion Pressure (CPP = MAP – ICP): Target CPP between 60–70 mmHg.
• Seizure Prophylaxis: Levetiracetam (or Phenytoin) for 7 days post-injury to prevent early post-traumatic seizures in severe/moderate TBI.

Anticoagulation Reversal:

• Warfarin: Prothrombin Complex Concentrate (PCC) + IV Vitamin K 10 mg.
• DOACs (Dabigatran / Factor Xa inhibitors): Idarucizumab (for Dabigatran) or Andexanet Alfa / PCC (for Rivaroxaban/Apixaban).

References

1. National Institute for Health and Care Excellence. Head injury: assessment and early management (NG232) [Internet]. 2023 [cited 2026 Aug 20]. Available from: https://www.nice.org.uk/guidance/ng232
2. Brain Trauma Foundation. Guidelines for the management of severe traumatic brain injury, 4th edition [Internet]. 2016 [updated 2020; cited 2026 Aug 20]. Available from: https://braintrauma.org/coma/guidelines/current