A 28-year-old motorcyclist is brought to A&E after a road traffic accident. He was not wearing a helmet. Bystanders report he was unconscious at the scene for approximately 5 minutes but appeared to wake up and speak before deteriorating again in the ambulance.
On arrival: GCS 9 (E2V2M5). BP 150/90, HR 58, RR 14. Right pupil 5mm, sluggishly reactive. Left pupil 3mm, briskly reactive.
What is the significance of the lucid interval? What does the right pupil tell you? What do you do next?
Classification of Head Injury
Head injuries are classified by severity using the Glasgow Coma Scale (GCS) on arrival after primary resuscitation:
| Severity | GCS | Characteristics | Management Setting |
|---|---|---|---|
| Minor | 13–15 | May have LOC <30 min, PTA <24hrs, normal CT | ED observation, discharge with head injury advice |
| Moderate | 9–12 | LOC or confusion, focal signs possible | Admission, CT, neurosurgical input |
| Severe | 3–8 | Unable to follow commands, high risk of intracranial injury | ICU, intubation, neurosurgical referral |
Intracranial Haematomas — Know the Differences
| Type | Source | CT Appearance | Classic History | Urgency |
|---|---|---|---|---|
| Extradural (EDH) | Middle meningeal artery (temporal bone fracture) | Biconvex (lens-shaped) hyperdense collection | Lucid interval — LOC, recovery, then rapid deterioration | Surgical emergency — minutes matter |
| Acute Subdural (ASDH) | Bridging veins | Crescent-shaped hyperdense collection following brain contour | High-energy trauma, immediate deterioration, elderly on anticoagulants | Urgent surgery if >10mm or significant shift |
| Chronic Subdural (CSDH) | Bridging veins — slow bleed | Crescent hypodense (dark) — weeks old | Elderly, minor trauma, gradual cognitive decline, headache | Burr hole drainage — semi-urgent |
| Intracerebral (ICH) | Brain parenchyma — contusion or hypertensive | Hyperdense within brain tissue | Focal deficits, variable conscious level | Medical management usually; surgery for accessible large haematomas |
The classic history of extradural haematoma: loss of consciousness → apparent recovery (lucid interval) → rapid secondary deterioration. This occurs because arterial bleeding from the middle meningeal artery gradually expands, initially compensated, then causing acute transtentorial herniation. The lucid interval is not always present — but when it is, it demands urgent CT and neurosurgical referral.
Primary Survey — ABCDE First
Head injury is not managed in isolation. Follow ATLS principles — a hypoxic or hypotensive patient with a head injury will have worse neurological outcomes than one who is adequately resuscitated. The brain hates hypoxia and hypotension.
Resuscitation Targets in Head Injury
- Airway: Protect early — GCS ≤8 warrants intubation. Assume C-spine injury until cleared.
- Breathing: Target SpO2 ≥94%, PaCO2 35–40 mmHg. Avoid hypocapnia (causes vasoconstriction) and hypercapnia (raises ICP).
- Circulation: Target SBP ≥110 mmHg in adults. A single episode of hypotension doubles mortality in severe TBI. Treat haemorrhagic shock aggressively.
- GCS: Assess after resuscitation — not before. A low GCS from shock will falsely suggest severe TBI.
- Pupils: Assess size, symmetry, reactivity. Unilateral fixed dilated pupil = ipsilateral herniation until proven otherwise.
CT Indications — When to Scan
Not every head injury needs a CT. The NICE head injury guidelines (widely used internationally) give clear indications. Scan within 1 hour if ANY of:
CT Head Indications (NICE)
- GCS <13 at any point since injury
- GCS 13–14 at 2 hours post-injury
- Suspected open or depressed skull fracture
- Signs of basal skull fracture — Battles sign (mastoid bruising), raccoon eyes (periorbital bruising), CSF rhinorrhoea/otorrhoea, haemotympanum
- Post-traumatic seizure
- Focal neurological deficit
- More than one episode of vomiting
- Amnesia >30 minutes before impact
- Age ≥65 with any LOC or amnesia
- Anticoagulation or coagulopathy with any LOC
Surgical Management
Extradural haematoma: Emergency craniotomy — evacuate haematoma and ligate middle meningeal artery. Time to surgery is critical — outcome directly correlates with GCS at time of surgery. Patients who reach theatre before secondary herniation have excellent outcomes.
Acute subdural haematoma: Craniotomy for haematoma >10mm thickness or midline shift >5mm, or GCS drop of ≥2 points. Outcome generally worse than EDH due to underlying brain injury.
Chronic subdural haematoma: Burr hole drainage under local anaesthetic in most cases. Recurrence in ~10% — may need repeat drainage or craniotomy.
Depressed skull fracture: Elevate if >1 table width depression, over eloquent cortex, or compound (open) fracture with dural breach.
Classic extradural haematoma — lucid interval followed by deterioration, right pupil dilatation indicating right-sided uncal herniation from right temporal EDH. Urgent CT confirmed right temporal extradural haematoma with 15mm midline shift. Taken directly to theatre — right temporal craniotomy, haematoma evacuated, middle meningeal artery ligated. Total time from arrival to theatre: 47 minutes. Post-operative GCS 14 by day 2. Discharged day 7 with no neurological deficit — an excellent outcome that was possible only because the team moved fast.
GCS after resuscitation — not before. The brain hates hypoxia and hypotension — treat both aggressively. Lucid interval = extradural haematoma until proven otherwise. EDH = biconvex on CT, arterial bleed, surgical emergency. ASDH = crescent on CT, venous bleed, worse prognosis. CSDH = elderly, hypodense on CT, burr hole drainage. Know your CT indications — when in doubt, scan.
References
- NICE Guideline NG232. Head injury: assessment and early management. National Institute for Health and Care Excellence. 2023.
- Brain Trauma Foundation. Guidelines for the Management of Severe Traumatic Brain Injury, 4th Edition. Neurosurgery. 2017;80(1):1–236.
- Bullock MR et al. Surgical management of acute subdural hematomas. Neurosurgery. 2006;58(3):S16–S24.
