Head Injury and the NICE CT Criteria

A head injury at the CST management and clinical station is a primary survey, a Glasgow Coma Scale score with a time, and a CT decision made from NICE NG232, published 18 May 2023. According to NG232, adults get a CT head within 1 hour of any high-risk factor being identified, within 8 hours of injury for a second list of factors when there has been loss of consciousness or amnesia, and a provisional radiology report within 1 hour of the scan. The candidate who can recite both lists, and say what they would do while waiting, scores.

Key takeaways

NG232 one-hour criteria for adults: GCS 12 or less on initial assessment, GCS under 15 at 2 hours after injury, suspected open or depressed skull fracture, any sign of basal skull fracture, post-traumatic seizure, focal neurological deficit, or more than one episode of vomiting
NG232 eight-hour criteria, for adults with loss of consciousness or amnesia: age 65 or over, any current bleeding or clotting disorder, a dangerous mechanism, or more than 30 minutes of retrograde amnesia; within the hour if presenting more than 8 hours after injury
A dangerous mechanism is a pedestrian or cyclist struck by a vehicle, an occupant ejected from a vehicle, or a fall from more than 1 m or 5 stairs
For a patient on anticoagulants or antiplatelets other than aspirin alone with no other indication, NG232 says to consider a CT within 8 hours of injury
A provisional written radiology report must be available within 1 hour of the CT
Observations are half-hourly until GCS is 15, then half-hourly for 2 hours, hourly for 4 hours, then 2-hourly; a sustained 1-point drop in GCS triggers urgent reassessment

How do I assess a patient with a head injury?

Assess a head injury with a trauma primary survey and the CCrISP structure: immediate ABCDE management with cervical spine protection, a GCS score recorded with its three components and the time, pupils, and glucose, then a full assessment of mechanism, amnesia, vomiting, seizures, anticoagulants and alcohol.

Say the GCS as eyes, verbal and motor rather than a single number, because NG232's deterioration criteria weight the motor component and the panel listens for that.

Look for the basal skull fracture signs the guideline names: haemotympanum, panda eyes, cerebrospinal fluid from the ear or nose, and Battle's sign. Each one is a one-hour CT on its own.

Which adults need a CT head within 1 hour?

Adults need a CT head within 1 hour of the risk factor being identified when NG232's high-risk list applies: a GCS of 12 or less on initial assessment, a GCS of less than 15 at 2 hours after the injury, a suspected open or depressed skull fracture, any sign of basal skull fracture, a post-traumatic seizure, a focal neurological deficit, or more than one episode of vomiting.

The two GCS thresholds are different numbers at different times, which is the trap. Twelve or less on arrival, or less than 15 two hours after the injury: a patient who is GCS 14 at hour two is a one-hour scan.

Which adults need a CT head within 8 hours?

Adults who have had some loss of consciousness or amnesia since the injury need a CT head within 8 hours of the injury if they are 65 or over, have any current bleeding or clotting disorder, had a dangerous mechanism, or have more than 30 minutes of retrograde amnesia.

NG232 adds a timing rule: for a patient presenting more than 8 hours after the injury with one of these factors, the CT is done within the hour. The dangerous mechanisms are a pedestrian or cyclist struck by a motor vehicle, an occupant ejected from a vehicle, or a fall from more than 1 metre or 5 stairs.

What changes if the patient takes an anticoagulant or antiplatelet?

If the patient takes an anticoagulant or an antiplatelet other than aspirin monotherapy and has no other indication for a scan, NG232 says to consider a CT head within 8 hours of the injury.

The guideline lists vitamin K antagonists, direct-acting oral anticoagulants, heparin and low molecular weight heparins, and it suggests scanning earlier where a risk assessment is difficult or the person might not return if they deteriorate. A current bleeding or clotting disorder with loss of consciousness is already on the 8-hour list.

Say that you would ask about reversal with haematology if the scan shows bleeding, because that is the next question.

When does the cervical spine need imaging?

The cervical spine needs a CT within 1 hour under NG232 when the GCS is 12 or less on initial assessment, the patient has been intubated, a definitive diagnosis is urgently needed for surgery or anaesthesia, there is blunt polytrauma involving the head and chest, abdomen or pelvis in an alert stable patient, or there is clinical suspicion of injury with a high-risk factor.

The high-risk factors with clinical suspicion include age 65 or over, a dangerous mechanism such as a fall from over 1 m or 5 stairs, an axial load, a high-speed or rollover collision, ejection, a motorised recreational vehicle or a bicycle collision, and focal peripheral neurology. Keep the collar on until it is cleared.

What is the management while awaiting the CT and after it?

While awaiting the CT the management is airway protection with cervical spine control, oxygen, avoidance of hypotension and hypoxia, glucose, analgesia and antiemetics, and observations at the frequency NG232 sets; after it, the plan follows the report, which must be available within 1 hour.

NG232 sets observations half-hourly until the GCS is 15, then, for a patient at 15, half-hourly for 2 hours, hourly for 4 hours and 2-hourly thereafter, reverting to half-hourly on any deterioration.

A positive scan means a discussion with neurosurgery. A negative scan in a patient still not at GCS 15 means continued observation and a low threshold to rescan, and the panel will ask who you would speak to.

What signs of deterioration trigger urgent reassessment?

NG232's signs of neurological deterioration are agitation or abnormal behaviour, a sustained drop of 1 point in GCS for at least 30 minutes with more weight on the motor score, a drop of 3 or more points in eye or verbal score or 2 or more in motor, severe or increasing headache or persistent vomiting, and new or evolving signs such as pupil inequality or asymmetry of limb or facial movement.

A supervising doctor does that reassessment, and it usually means an immediate repeat CT and a neurosurgical call. Say that you would go to the bedside, not review the chart from the office.

Who do I escalate a head injury to?

Escalate a head injury to your registrar for any one-hour criterion, to the anaesthetist for a GCS of 8 or less or a threatened airway, and to the regional neurosurgical unit for any intracranial bleed, a deteriorating GCS, or a persistent GCS below 15 with an unexplained scan.

Give the neurosurgeon the GCS components with times, pupils, the mechanism, anticoagulants, the CT findings and the observations trend. That single call is the thing the panel is most likely to make you rehearse.

How this comes up at the CST interview

The head injury scenario is a 70-year-old on warfarin who fell down six stairs, is GCS 14, and has vomited twice, and the panel wants you to find the one-hour criterion, the anticoagulant, and the cervical spine in your first minute.

Follow-ups ask what observation frequency you would prescribe, what a one-point drop in GCS obliges you to do, and how you would speak to the neurosurgical registrar at a hospital 50 miles away.

The coresurgeryinterview bank has a scored head injury scenario with AI-marked spoken practice among its 299 questions: /Question-Bank/Sample-Questions.

FAQ

What are the NICE one-hour CT head criteria for adults?

Under NG232: GCS 12 or less on initial assessment, GCS under 15 at 2 hours after the injury, suspected open or depressed skull fracture, any sign of basal skull fracture, post-traumatic seizure, focal neurological deficit, or more than one episode of vomiting.

What are the eight-hour CT head criteria?

For adults with loss of consciousness or amnesia: age 65 or over, any current bleeding or clotting disorder, a dangerous mechanism, or more than 30 minutes of retrograde amnesia. If they present more than 8 hours after injury, the scan is done within the hour.

Does a patient on a DOAC need a CT after a minor head injury?

NG232 says to consider a CT within 8 hours of injury for someone on anticoagulant treatment or antiplatelet treatment other than aspirin alone who has no other indication, and to consider it sooner if risk assessment is difficult or they may not return.

How often should observations be done after a head injury?

Half-hourly until the GCS is 15; then for a patient at 15, half-hourly for 2 hours, hourly for 4 hours, then 2-hourly. Any deterioration returns the patient to half-hourly observations and the original schedule.

What GCS change counts as deterioration?

NG232 lists a sustained drop of 1 point for at least 30 minutes, with more weight on the motor score, a drop of 3 or more in eye or verbal response, or 2 or more in motor response, alongside agitation, worsening headache, persistent vomiting or new focal signs.

How quickly must the CT be reported?

NG232 says a provisional written radiology report should be available within 1 hour of the CT scan.

When does the neck need a CT?

Within 1 hour if the GCS is 12 or less, the patient is intubated, a definitive diagnosis is urgently needed, there is blunt polytrauma with the head and torso in an alert stable patient, or there is clinical suspicion of cervical injury with a high-risk factor such as age 65 or over or a dangerous mechanism.