Traumatic Brain Injury

TBI Introduction - Brainy Bruises

• Definition: Acquired brain injury from external mechanical force, impairing cognitive, physical, or psychosocial functions.
• Types:
  • Primary: Occurs at impact (e.g., skull fracture, contusion, laceration, DAI).
  • Secondary: Evolves post-impact (systemic: hypoxia, hypotension; intracranial: ↑ICP, edema); exacerbates damage.
• Pediatric Causes:
  • Falls (most common, esp. <2 yrs).
  • MVAs (leading TBI death cause).
  • Sports injuries.
  • NAT/AHT (significant morbidity).
• Epidemiology:
  • Major cause of death & disability in children >1 yr.
  • Peaks: <5 yrs & 15-19 yrs.
  • Boys > Girls.
• ⭐ High-Yield:

  Growing skull fracture (leptomeningeal cyst): rare in infants. Dural tear beneath fracture allows herniation, prevents healing, causes progressive enlargement.

Clinical Assessment - Spotting Trouble

• Primary Survey (ABCDE): Rapidly assess Airway, Breathing, Circulation, Disability (GCS, pupils), Exposure.
• History: Mechanism (e.g., fall >3ft or 5 stairs if <2y, >5ft if ≥2y), LOC duration, amnesia, seizures, vomiting (≥3 episodes).
• Examination Findings:
  • Vitals: Cushing's triad (late sign: ↑BP, ↓HR, irregular respirations).
  • Head: Scalp hematoma/laceration, palpable fracture, Battle's sign (mastoid ecchymosis), Raccoon eyes (periorbital ecchymosis).
  • Fontanelle (infants): Bulging, tense.
  • Neuro: Pediatric GCS (PGCS), pupillary asymmetry/reactivity, focal deficits, posturing.
• Age-Specific Signs:
  • Infants: Persistent irritability, lethargy, poor feeding, high-pitched cry.
  • Children: Headache, dizziness, amnesia, visual changes.
• Severity (PGCS): Mild (13-15), Moderate (9-12), Severe (≤8).

  ⭐ A drop in GCS by ≥2 points is a critical sign of neurological worsening requiring urgent intervention.

• Red Flags: Deteriorating GCS, new/worsening focal neurological signs, persistent vomiting, seizures, signs of skull fracture.

Imaging & Diagnosis - Peeking Inside

• Initial Choice: Non-contrast CT (NCCT) head is the primary imaging modality for acute TBI.
• CT Indications (PECARN 📌):
  • Age <2 yrs: GCS <15, palpable skull Fx, LOC >5s, non-frontal scalp hematoma, severe mechanism.
  • Age ≥2 yrs: GCS <15, basilar skull Fx signs, LOC, vomiting, severe headache, severe mechanism.
• MRI: Superior for non-accidental injury (NAI), persistent neurological deficits despite normal CT, or assessing late sequelae like Diffuse Axonal Injury (DAI).
• Skull X-ray: Limited role; CT preferred for brain injury assessment.
• Lesion Types: Epidural (EDH), Subdural (SDH), Subarachnoid (SAH), Intracerebral, Diffuse Axonal Injury (DAI).

⭐ Epidural hematoma (EDH) classically presents with a "lucid interval" before neurological deterioration.

Management Principles - Healing Heads

• Initial Stabilization (ABCDE):
  • Airway: Intubate if GCS ≤ 8.
  • Breathing: Oxygenation.
  • Circulation: Maintain MAP; avoid hypotension.
  • Disability: GCS, pupils.
  • Exposure: Normothermia.
• ICP Monitoring: If GCS ≤ 8 & abnormal CT. Target ICP < 20 mmHg.
• Raised ICP Management (Tiered):
  • Tier 0: Head elevation 30° (midline), analgesia/sedation.
  • Tier 1: Mannitol (0.25-1 g/kg) OR Hypertonic Saline (3% 2-5 ml/kg); CSF drainage.
  • Tier 2: Mild hyperventilation (PaCO₂ 30-35 mmHg); optimize CPP (50-70 mmHg).
  • Tier 3: Barbiturate coma, decompressive craniectomy.

⭐ Cushing's Triad (hypertension, bradycardia, irregular respirations) is a LATE, ominous sign of severely ↑ICP & impending herniation.

High‑Yield Points - ⚡ Biggest Takeaways

• Glasgow Coma Scale (GCS) is crucial for assessment; use Pediatric GCS for non-verbal children.
• Suspect Non-Accidental Trauma (NAT) with findings like subdural hematomas, retinal hemorrhages, or inconsistent history.
• Cushing's triad (hypertension, bradycardia, irregular breathing) signals critically elevated Intracranial Pressure (ICP).
• Management prioritizes preventing secondary brain injury: optimize oxygenation, perfusion; avoid hypotension and hypoxia.
• Mannitol or 3% hypertonic saline are first-line for acute ↑ ICP; consider decompressive craniectomy if refractory.