01OverviewDefinition, clinical context and the essential points that orientate the chapter.
Head-injury assessment begins with physiology rather than a CT checklist. Protect the airway and cervical spine, provide oxygen when needed, treat hypotension with blood or appropriate fluid, check glucose and control external bleeding. Document the GCS components instead of only the total because a change in motor response carries different significance from speech affected by intoxication. Examine pupils, cranial nerves, limbs and signs of skull fracture before analgesia or sedation when safe.
NICE CT criteria use risk and timing. In adults, the high-risk group receives CT within one hour: initial GCS twelve or less, GCS below fifteen at two hours, suspected open or depressed skull fracture, basal-skull signs, post-traumatic seizure, focal deficit or more than one vomit. A second group with loss of consciousness or amnesia receives CT within eight hours when age, coagulopathy, dangerous mechanism or prolonged retrograde amnesia adds risk; late presenters are scanned within one hour.
Antithrombotic treatment requires precise history. Identify warfarin, a direct oral anticoagulant, heparin and antiplatelet drugs, last dose, indication, renal function and adherence. NICE advises considering CT within eight hours for anticoagulants or antiplatelets other than aspirin monotherapy even without another indication, or within one hour when the patient presents more than eight hours after injury. A normal INR does not exclude direct-oral-anticoagulant activity.
Paediatric criteria account for development. A GCS below fifteen in a baby under one year, tense fontanelle, suspected non-accidental injury, seizure, focal deficit or skull-fracture signs drives urgent imaging. Some intermediate features require observation, with CT if further vomiting, abnormal drowsiness or GCS decline occurs. Use paediatric radiology protocols and weight-based medicines. A child who cannot give a history needs careful behaviour and safeguarding assessment.
CT defines acute structural injury but does not replace observation. Review for extradural or subdural blood, contusion, subarachnoid blood, fracture, pneumocephalus, mass effect and basal cisterns; request cervical imaging where indicated. Discuss abnormalities with neurosurgery according to local network criteria. A deteriorating patient may need airway control, hyperosmolar rescue under specialist protocol and immediate transfer; do not wait for every laboratory result before calling.
Observation is active. Repeat GCS components, pupils, limb power, pulse, pressure, respiratory rate, temperature and oxygen saturation at a frequency determined by risk and local protocol. New agitation, headache, vomiting, drowsiness or focal change triggers reassessment and often CT. Analgesia and antiemetic treatment improve examination; sedation that obscures neurological trend needs senior justification and airway monitoring.
Safe discharge requires clinical and social criteria. The patient should be at GCS fifteen or documented baseline, have no admission indication, tolerate appropriate care and have a responsible adult able to observe. Provide written and verbal warning signs, emergency contact route, advice that symptoms can evolve, gradual return to school, work and sport, and driving restriction while impaired. Communicate safeguarding concerns and anticoagulant restart or reversal plans explicitly.
Key points
- Record GCS eye, verbal and motor components, pupils, focal neurology, amnesia, loss of consciousness, vomiting, seizure, mechanism, alcohol or drugs, anticoagulants and time since injury.
- Stabilise airway, oxygenation and circulation with cervical protection before imaging; one episode of hypotension or hypoxaemia can worsen neurological outcome.
- Adults need CT head within 1 hour for GCS 12 or less initially, GCS below 15 at 2 hours, suspected open or depressed fracture, basal-skull sign, post-traumatic seizure, focal deficit or more than one vomiting episode.
- Adults with loss of consciousness or amnesia need CT within 8 hours, or within 1 hour if presenting after 8 hours, when age 65 or over, a bleeding or clotting disorder, dangerous mechanism or more than 30 minutes retrograde amnesia is present.
- Children use age-specific NICE criteria and observation: do not transfer adult vomiting or GCS rules uncritically to infants and younger children.
- Consider CT within 8 hours for anticoagulant treatment or antiplatelet treatment other than aspirin alone even when no other CT indication exists; use 1-hour imaging if presenting more than 8 hours after injury.
- Discuss surgically significant CT findings, persistent coma, unexplained deterioration or refractory symptoms promptly with neurosurgery and include image transfer, physiology and anticoagulant status.
- Discharge only when GCS is 15 or baseline, significant injury is excluded, supervision is reliable and written and verbal advice covers deterioration, rest, return to activity, driving and responsible-adult observation.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Direct impact
Falls, road collisions, assault and sport transmit linear or rotational energy to scalp, skull and brain, with severity not reliably predicted by external injury.
Acceleration and rotation
Rapid movement and deceleration shear axons and bridging veins without a skull strike, causing diffuse injury or subdural bleeding.
Physiological vulnerability
Very young or older age, alcohol, anticoagulation, bleeding disorders and previous neurosurgery alter bleeding risk, examination reliability and imaging threshold.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Primary structural injury
Impact causes contusion, laceration, fracture, vascular disruption and axonal damage at the moment of trauma, which resuscitation cannot reverse.
- 2Expanding mass lesion
Extradural, subdural or intraparenchymal blood raises intracranial pressure and can shift brain tissue, compress cranial nerves and reduce cerebral perfusion.
- 3Secondary brain injury
Hypoxaemia, hypotension, seizures, fever, dysglycaemia and abnormal carbon dioxide worsen injured tissue and are preventable targets during assessment and transfer.
- 4Concussion physiology
Transient network and metabolic disturbance can cause symptoms despite normal structural imaging; a normal CT does not mean the brain has recovered.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
A two-point or progressive decline, new inability to localise or failure to reach expected baseline demands immediate ABC reassessment, CT and neurosurgical escalation.
CSF leak, haemotympanum, periorbital bruising, mastoid bruising or facial nerve deficit indicates fracture and triggers CT without testing leaking fluid at bedside.
Pupil asymmetry, posturing, worsening consciousness, bradycardia with hypertension or irregular breathing suggests herniation physiology and an airway-neurosurgical emergency.
Recent anticoagulant exposure, impaired renal clearance or high INR raises concern for delayed or expanding bleeding even after a low-energy mechanism.
Abnormal drowsiness, repeated vomiting, irritability, tense fontanelle, seizure or altered behaviour reported by carers may be the key neurological change.
Stable normal neurological examination, improving symptoms, no CT or admission criterion and dependable home supervision support discharge with safety-netting.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
First-line CT head for acute structural injuryFirst stepFirst line - Why
- Identify haemorrhage, fracture, mass effect and surgical lesions within NICE timing.
- Interpretation and limitations
- Use non-contrast CT initially; one-hour and eight-hour pathways depend on age, GCS, signs, mechanism, amnesia and antithrombotic treatment rather than clinician reassurance alone.
- 02
CT cervical spine - Why
- Detect associated cervical fracture or instability when head injury makes examination unreliable.
- Interpretation and limitations
- Apply NICE spinal criteria and reconstruct from trauma CT when appropriate; persistent neurological signs attributable to cord injury may require MRI after CT.
- 03
Blood glucose - Why
- Exclude a rapidly reversible cause of reduced consciousness or seizure.
- Interpretation and limitations
- Correct hypoglycaemia promptly, but improvement does not automatically exclude concomitant head injury or remove CT indications.
- 04
FBC, coagulation and renal profile - Why
- Assess bleeding, anaesthesia and anticoagulant-reversal context.
- Interpretation and limitations
- INR measures warfarin effect; routine PT and APTT have variable sensitivity to DOACs, so identify drug and last dose and use specific testing when available.
- 05
Observation chart - Why
- Detect dynamic neurological deterioration when CT is deferred or after imaging.
- Interpretation and limitations
- Trend GCS components, pupils, limb movement and vital signs; any worsening resets the clinical assessment and can create a new immediate CT indication.
- 06
MRI brain - Why
- Investigate selected persistent or unexplained neurological deficits after acute stabilisation.
- Interpretation and limitations
- MRI is more sensitive for diffuse axonal and some posterior-fossa injury but is slower and is not the first-line scan for an acutely deteriorating patient.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Intoxication
Alcohol and sedatives cause ataxia and reduced consciousness, but must not be accepted as the explanation until intracranial injury, hypoxia and hypoglycaemia are excluded.
Stroke or spontaneous bleed
Focal deficit or sudden collapse may have preceded the fall; CT pattern, history and vascular imaging distinguish a medical event causing trauma.
Postictal state
Seizure can cause both transient reduced GCS and head injury, so witness history, glucose, examination and imaging criteria are considered together.
Cervical spine injury
Neck pain, limb symptoms, altered consciousness and high-risk mechanism require simultaneous spinal assessment because neurological signs may not arise from the brain.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01ImmediateStabilise and risk stratifyFirst stepAny patient presents after head trauma with symptoms, altered consciousness or concerning mechanism.+
- 1Run ABCDE with cervical protection, correct hypoxia, hypotension and glucose, control bleeding and call anaesthetic help for an unprotected airway.
- 2Record GCS components, pupils, focal neurology, fracture signs, vomiting, seizure, amnesia, mechanism, medicines and time from injury.
- 3Apply adult or paediatric NICE CT criteria and book the scan within the required one-hour or eight-hour interval from risk identification.
- 4EscalationEscalate falling GCS, pupil change or posturing to trauma, anaesthetic and neurosurgical teams while resuscitation and imaging proceed.
02After CTObserve, reverse or transferImaging is complete or a high-risk patient remains under observation.+
- 1Discuss intracranial blood, mass effect, depressed or basal fracture and clinical-imaging discordance through the neurosurgical network with images available.
- 2Stop and reverse clinically significant anticoagulation for traumatic intracranial bleeding using the current agent-specific emergency protocol.
- 3EscalationContinue neurological and physiological observations and repeat CT or escalate if GCS, pupils, focal signs, headache or vomiting worsens.
- 4Admit when symptoms, social circumstances, intoxication, other injuries or unreliable observation make discharge unsafe even if CT is normal.
03DischargeProvide safe recovery adviceSignificant injury has been excluded and neurological status is GCS 15 or documented baseline.+
- 1Confirm a responsible adult can supervise and understands which symptoms require immediate return to emergency care.
- 2Give matched written and verbal advice on headache, vomiting, drowsiness, seizure, weakness, fluid from nose or ear and behavioural change.
- 3Advise gradual return to cognitive and physical activity, no same-day sport and no driving or hazardous work while symptoms impair safety.
- 4Arrange GP, concussion, neurosurgical, safeguarding or anticoagulation follow-up according to symptoms, findings and treatment changes.
Key medicines and prescribing safety1 treatment · regimens, roles and cautions+
Paracetamol for uncomplicated head-injury pain
Give 1 g orally up to four times daily when required, at least 4 hours apart, with a maximum of 4 g in 24 hours; use a lower maximum for low body weight, frailty, malnutrition or liver risk.Check combination products and overdose risk, avoid exceeding the total daily maximum and do not use symptom relief to dismiss worsening intracranial signs.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Intracranial haematoma
Extradural, subdural or intraparenchymal bleeding may expand after an initially lucid interval and requires urgent neurosurgical discussion.
Raised intracranial pressure
Falling consciousness, pupillary asymmetry, hypertension with bradycardia and abnormal posturing indicate advanced pressure effects and possible herniation.
Post-traumatic seizure
Early seizure worsens oxygen demand and aspiration risk, while later epilepsy risk depends on injury severity and structural damage.
Persistent post-concussion symptoms
Headache, dizziness, cognitive slowing, sleep disruption and mood symptoms can impair education, work and driving despite no acute CT lesion.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Repeat GCS components, pupil size and reaction, limb power and vital signs at the local head-injury observation frequency and after any sedative or transfer.
- Document the exact time each CT indication was identified, requested, performed and reported, with direct communication of critical findings.
- Reassess headache, vomiting, behaviour, balance and amnesia; a worsening trajectory matters even if the original CT was normal.
- After anticoagulant reversal, trend neurological status, haemoglobin and agent-relevant coagulation while planning thrombosis prevention and eventual restart.
- Ensure the discharge advice recipient, responsible observer, transport, emergency return route and follow-up plan are all recorded.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
GCS components carry meaning
A total score can hide a new motor decline or language problem and should never replace eye, verbal and motor documentation.
CT timing starts at indication
Operational delays should be visible; recording only scan completion obscures whether the one-hour standard was met.
Normal CT is not normal function
Concussion symptoms can be substantial despite no acute structural lesion and need paced recovery advice.
Late presentation shortens the wait
When an eight-hour risk patient arrives after that interval, NICE moves imaging to within one hour rather than adding another eight hours.
Supervision is a clinical criterion
A neurologically reassuring patient without reliable observation may still require admission or another safe arrangement.
11Common pitfallsFrequent interpretation and management errors.
- 01
Attributing reduced consciousness to alcohol before excluding hypoxia, glucose abnormality and intracranial injury.
- 02
Recording only a total GCS without its components, pupils and trend.
- 03
Using adult CT criteria unchanged in an infant or child.
- 04
Assuming normal PT or APTT excludes clinically relevant direct oral anticoagulation.
- 05
Calling a normal CT proof that concussion symptoms are fabricated or resolved.
- 06
Discharging without a responsible observer and matched written and verbal warning signs.