Key Facts

Head injury is one of the most common reasons for emergency department attendance. The vast majority are mild, but identifying patients at risk of significant intracranial pathology is critical. Traumatic brain injury (TBI) is the leading cause of death and disability in adults under 40.

Epidemiology

Approximately 1.4 million head injury attendances per year in England and Wales. ~200,000 require admission. ~5,000 deaths per year from TBI. Falls are the most common mechanism in all ages; RTCs are the most common mechanism in young adults. Male:female ratio is 2:1.

Aetiology

• Falls: Most common overall (especially elderly)
• Road traffic collisions: Most common in 15-30 age group
• Assaults: Common in young men
• Sports: Rugby, horse-riding, cycling
• Non-accidental injury: Consider in children with unexplained or inconsistent injuries

Pathophysiology

Primary brain injury: Occurs at the time of impact — contusion, diffuse axonal injury (DAI), intracranial haemorrhage. Largely irreversible.

Secondary brain injury: Develops hours to days after — caused by hypoxia, hypotension, raised ICP, cerebral oedema, seizures, infection. The focus of management is to PREVENT secondary injury.

Raised ICP: Monro-Kellie doctrine — fixed cranial volume means any increase in one compartment (blood, brain, CSF) must be compensated or ICP rises. Normal ICP 5-15 mmHg. CPP = MAP − ICP; target CPP >60 mmHg.

GCS Assessment

Severity Classification

• Mild: GCS 13-15
• Moderate: GCS 9-12
• Severe: GCS 3-8 (requires intubation and ventilation)

Intracranial Haemorrhage Types

• Extradural: Lucid interval, middle meningeal artery, biconvex on CT, rapid deterioration
• Acute subdural: Crescent-shaped, bridging veins, associated brain injury, high mortality
• Subarachnoid: Traumatic or spontaneous, blood in sulci/cisterns
• Intracerebral contusion/haemorrhage: Coup and contrecoup injuries

Red Flags (NICE CG176 — Immediate CT)

• GCS <13 at any point since injury
• GCS <15 at 2 hours after injury
• Suspected skull fracture (open, depressed, base of skull)
• Post-traumatic seizure
• Focal neurological deficit
• ≥2 episodes of vomiting
• On anticoagulants/bleeding disorder

Bedside

• GCS: Serial assessment (every 30 min initially, increase frequency if deteriorating)
• Pupil assessment: Size, reactivity, asymmetry — unilateral fixed dilated pupil = uncal herniation
• Blood glucose: Exclude hypoglycaemia
• C-spine assessment: Assume injury until cleared

Bloods

• FBC, U&Es, coagulation (INR): Baseline and guide anticoagulant reversal
• Group and save: If surgical intervention anticipated
• Blood alcohol/toxicology: If intoxication suspected (may confound GCS)

Imaging

• CT head (non-contrast): Gold standard — as per NICE CG176 criteria
• CT C-spine: For all patients with GCS <13, intubated, or with risk factors per NICE
• CT angiography: If vascular injury suspected (e.g., skull base fracture near carotid canal)
• MRI brain: For diffuse axonal injury (more sensitive than CT), posterior fossa lesions, and prognostication

Special Tests

• ICP monitoring: Intraparenchymal bolt or EVD — for severe TBI (GCS ≤8 with abnormal CT)
• EEG: If seizures suspected
• CT perfusion/Xenon CT: Research/specialist use for cerebral blood flow assessment

Non-pharmacological

• ABCDE assessment: As per ATLS primary survey
• C-spine immobilisation: Until cleared
• Head-up positioning: 30° to aid venous drainage and reduce ICP
• Avoid secondary insults: Maintain normoxia (PaO2 >13 kPa), normocapnia (PaCO2 4.5-5.0 kPa), normothermia, normoglycaemia
• Target SBP >110 mmHg: Hypotension is devastating in TBI

Pharmacological

• Anticoagulant reversal: Warfarin — vitamin K 5-10mg IV + PCC (Beriplex); DOAC — idarucizumab (dabigatran) or andexanet alfa (factor Xa inhibitors)
• Mannitol 20% (0.25-1g/kg IV) or hypertonic saline 3-5% (2-5mL/kg): For acute raised ICP/herniation — temporising measure
• Anti-epileptics: Levetiracetam 500mg-1g IV or phenytoin 15-18mg/kg IV — for post-traumatic seizures (not routine prophylaxis beyond 7 days)
• Analgesia: Paracetamol 1g QDS; avoid NSAIDs (bleeding risk); codeine for moderate pain
• VTE prophylaxis: Balance bleeding risk — LMWH typically started after 24-48h if stable on repeat imaging

Surgical/Interventional

• Emergency craniotomy: Extradural haematoma (>30mL or midline shift >5mm), acute SDH with midline shift
• Decompressive craniectomy: Refractory raised ICP (RESCUEicp trial — improves survival but increases severe disability)
• EVD (External Ventricular Drain): For acute hydrocephalus
• ICP monitoring: For GCS ≤8 with abnormal CT — target ICP <22 mmHg

Referral Criteria

• GCS ≤8 — neurosurgical referral and ICU
• Intracranial haemorrhage requiring surgery — neurosurgery
• Skull fracture (depressed, base of skull) — neurosurgical assessment
• Deteriorating GCS — urgent repeat CT and neurosurgical consultation
• All children with non-accidental injury concerns — safeguarding referral

• Mild TBI (GCS 13-15): >95% make good recovery; ~15% have persistent post-concussion symptoms at 3 months
• Moderate TBI (GCS 9-12): ~80% survive; many have significant disability
• Severe TBI (GCS 3-8): Mortality ~30-40%; ~50% of survivors have moderate-severe disability
• Extradural haematoma: Excellent prognosis if operated early (mortality <5%); poor if late (herniation)
• Acute subdural: Mortality ~50-60%; depends on degree of underlying brain injury
• Diffuse axonal injury: Leading cause of persistent vegetative state post-TBI

NICE CG176 CT Head Criteria

GCS and TBI Severity

Base of Skull Fracture Signs