Key Facts

Extradural haematoma (EDH) is a neurosurgical emergency where prompt recognition and surgical treatment are life-saving. It is classically seen in young patients after temporal bone trauma. The lucid interval is a well-known but not universal feature.

Epidemiology

Incidence ~1-4% of head-injury admissions; overall ~2 per 100,000 per year. Peak age 20-30 years (young adults). Male predominance (4:1). Rare in the very young (<2 years — dura more adherent to skull) and elderly (dura more adherent).

Aetiology

• Arterial (~90%): middle meningeal artery rupture — usually following temporal/parietal skull fracture
• Venous (~10%): dural venous sinus tear (posterior fossa EDH — from transverse sinus) or meningeal vein; these accumulate more slowly
• Skull fracture: present in ~75-95% of adult EDH cases

Pathophysiology

Trauma → temporal bone fracture → middle meningeal artery laceration → arterial bleeding into extradural (epidural) space → haematoma expands, stripping dura from inner skull table. The dura is firmly attached at suture lines, limiting spread (biconvex shape). Expanding haematoma → raised ICP → ipsilateral uncal herniation → CN III compression (ipsilateral dilated pupil) → brainstem compression → contralateral hemiparesis → death if untreated. The lucid interval represents the time between recovery from initial concussion and deterioration from expanding haematoma.

Classic Presentation ("Lucid Interval")

1. Initial injury: brief loss of consciousness (concussion)
2. Lucid interval: apparent recovery (patient alert and orientated) — minutes to hours
3. Deterioration: headache → drowsiness → rapid decline in GCS → coma → death

Clinical Signs

• Ipsilateral fixed dilated pupil (CN III compression — first sign of uncal herniation)
• Contralateral hemiparesis (cerebral peduncle compression)
• Cushing response: hypertension + bradycardia + irregular respirations (brainstem compression — late and ominous)
• Scalp swelling/bruising over temporal region
• Seizures (~10%)

Important Notes

• Lucid interval occurs in only ~30% — many patients have persistent reduced GCS
• Some patients may not lose consciousness initially ("talk and deteriorate")

Red Flags

• Any head-injury patient who deteriorates after initial improvement
• Fixed dilated pupil in head-injured patient
• Cushing response (imminent brainstem herniation)
• GCS drop ≥2 points (NICE CG176 — urgent CT)

Imaging

• CT head (non-contrast): IMMEDIATE — biconvex (lens-shaped) hyperdense collection; usually temporal/temporoparietal; does NOT cross suture lines; look for:
  • Midline shift (>5 mm = significant)
  • Mass effect on ipsilateral ventricle (compression/effacement)
  • Associated skull fracture
  • Underlying brain injury
• Skull X-ray: NOT indicated (CT is definitive); if done, may show temporal fracture

Bloods

• FBC, coagulation: baseline
• Group and crossmatch: for surgery
• U&Es: baseline

NICE CG176 Indications for CT Head (Head Injury)

• GCS <13 at any point
• GCS <15 at 2 hours post-injury
• Suspected skull fracture
• Post-traumatic seizure
• Focal neurological deficit

• 1 episode of vomiting

• Loss of consciousness/amnesia + age ≥65, coagulopathy, or dangerous mechanism

Emergency

• A-E assessment: protect airway if GCS ≤8 (intubate)
• Immediate CT head: do NOT delay for any reason if clinically suspected
• Emergency craniotomy: for evacuation of haematoma if:
  • Haematoma thickness >15 mm
  • Midline shift >5 mm
  • GCS <9 or deteriorating GCS
  • Pupil abnormality
  • Any symptomatic EDH requires urgent surgical discussion
• Burr hole: may be performed as temporising measure if craniotomy not immediately available ("burr hole and pray")

Intraoperative

• Craniotomy: bone flap raised over haematoma
• Haematoma evacuated
• Bleeding source identified and controlled (middle meningeal artery — coagulation, wax, or ligation)
• Dura may be tacked to skull to prevent reaccumulation

Post-operative

• ITU/HDU monitoring
• Serial neurological observations
• Post-op CT: confirm evacuation, exclude reaccumulation
• Seizure prophylaxis: consider short course (levetiracetam or phenytoin)

Conservative

• Small, asymptomatic EDH (<15 mm, midline shift <5 mm, GCS 15): may be managed conservatively with close observation and serial CT
• Must have neurosurgical availability for emergency surgery

Referral Criteria

• All EDH: immediate neurosurgical referral
• Any deteriorating head-injured patient: immediate CT and neurosurgical contact

With prompt surgical evacuation: mortality <5%; good functional outcome in most cases. Without treatment: mortality approaches 100% (fatal herniation). Pre-operative GCS is the strongest prognostic factor: GCS 8-15 pre-op has excellent outcomes; GCS 3-5 pre-op has ~35% mortality despite surgery. The "talk and die" patient highlights the importance of serial neurological monitoring in all head injuries. Posterior fossa EDH has worse prognosis due to rapid brainstem compression. Overall, EDH has significantly better outcomes than acute SDH (less associated parenchymal injury).

EDH vs SDH Comparison

NICE CG176 CT Head Criteria (Key Points)