Focal neurological deficit

Problems restricted to a particular part of the body or a particular activity, for example, difficulties with understanding, speaking, reading or writing; decreased sensation; loss of balance; general weakness; visual changes; abnormal reflexes; and problems walking.

High-energy head injury

For example, pedestrian struck by motor vehicle, occupant ejected from motor vehicle, fall from a height of greater than 1 metre or more than 5 stairs, diving accident, high-speed motor vehicle collision, rollover motor accident, accident involving motorised recreational vehicles, bicycle collision, or any other potentially high-energy mechanism.

Base of open or depressed skull fracture or penetrating head injury

Signs include clear fluid running from the ears or nose, black eye with no associated damage around the eyes, bleeding from one or both ears, bruising behind one or both ears, penetrating injury signs, visible trauma to the scalp or skull of concern to the professional.

Telephone advice services

1.1.2.

Telephone advice services (for example, NHS 111, emergency department helplines) should refer patients who have sustained a head injury to the emergency ambulance services (that is, 999) for emergency transport to the emergency department if they have experienced any of the following:

• Unconsciousness or lack of full consciousness (for example, problems keeping eyes open).
• Any focal neurological deficit since the injury.
• Any suspicion of a skull fracture or penetrating head injury.
• Any seizure (‘convulsion’ or ‘fit’) since the injury.
• A high-energy head injury.
• The injured person or their carer is incapable of transporting the injured person safely to the hospital emergency department without the use of ambulance services (providing any other risk factor indicating emergency department referral is present; see recommendation 1.1.3). [2003, amended 2007 and 2014]

1.1.3.

Telephone advice services (for example, NHS 111 or emergency department helplines) should refer patients who have sustained a head injury to a hospital emergency department if they have any of the following risk factors:

• Any loss of consciousness (‘knocked out’) as a result of the injury, from which the person has now recovered.
• Amnesia for events before or after the injury (‘problems with memory’)^[4].
• Persistent headache since the injury.
• Any vomiting episodes since the injury.
• Any previous brain surgery.
• Any history of bleeding or clotting disorders.
• Current anticoagulant therapy.
• Current drug or alcohol intoxication.
• There are any safeguarding concerns (for example, possible non-accidental injury or a vulnerable person is affected).
• Irritability or altered behaviour (‘easily distracted’, ‘not themselves’, ‘no concentration’, ‘no interest in things around them’), particularly in infants and children aged under 5 years.
• Continuing concern by helpline staff about the diagnosis. [2003, amended 2014]

Community health services and NHS minor injury clinics

1.1.4.

Community health services (GPs, ambulance crews, NHS walk-in centres, dental practitioners) and NHS minor injury clinics should refer patients who have sustained a head injury to a hospital emergency department, using the ambulance service if deemed necessary, if any of the following are present:

• Glasgow coma scale (GCS) score of less than 15 on initial assessment.
• Any loss of consciousness as a result of the injury.
• Any focal neurological deficit since the injury.
• Any suspicion of a skull fracture or penetrating head injury since the injury.
• Amnesia for events before or after the injury^[4].
• Persistent headache since the injury.
• Any vomiting episodes since the injury (clinical judgement should be used regarding the cause of vomiting in those aged 12 years or younger and the need for referral).
• Any seizure since the injury.
• Any previous brain surgery.
• A high-energy head injury.
• Any history of bleeding or clotting disorders.
• Current anticoagulant therapy.
• Current drug or alcohol intoxication.
• There are any safeguarding concerns (for example, possible non-accidental injury or a vulnerable person is affected).
• Continuing concern by the professional about the diagnosis. [2003, amended 2007 and 2014]

1.1.5.

In the absence of any risk factors in recommendation 1.1.4, consider referral to an emergency department if any of the following factors are present, depending on judgement of severity:

• Irritability or altered behaviour, particularly in infants and children aged under 5 years.
• Visible trauma to the head not covered in recommendation 1.1.4 but still of concern to the professional.
• No one is able to observe the injured person at home.
• Continuing concern by the injured person or their family or carer about the diagnosis. [2003, amended 2014]

Transport to hospital from community health services and NHS minor injury clinics

1.1.6.

Patients referred from community health services and NHS minor injury clinics should be accompanied by a competent adult during transport to the emergency department. [2003]

1.1.7.

The referring professional should determine if an ambulance is required, based on the patient’s clinical condition. If an ambulance is deemed not required, public transport and car are appropriate means of transport providing the patient is accompanied. [2003]

1.1.8.

The referring professional should inform the destination hospital (by phone) of the impending transfer and in non-emergencies a letter summarising signs and symptoms should be sent with the patient. [2003]

Training in risk assessment

1.1.9.

GPs, nurse practitioners, dentists and ambulance crews should receive training, as necessary, to ensure that they are capable of assessing the presence or absence of the risk factors listed in recommendations 1.1.4 and 1.1.5. [2003, amended 2007]

Glasgow coma scale

1.2.1.

Base monitoring and exchange of information about individual patients on the three separate responses on the GCS (for example, a patient scoring 13 based on scores of 4 on eye-opening, 4 on verbal response and 5 on motor response should be communicated as E4, V4, M5). [2003]

1.2.2.

If a total score is recorded or communicated, base it on a sum of 15, and to avoid confusion specify this denominator (for example, 13/15). [2003]

1.2.3.

Describe the individual components of the GCS in all communications and every note and ensure that they always accompany the total score. [2003]

1.2.4.

In the paediatric version of the GCS, include a ‘grimace’ alternative to the verbal score to facilitate scoring in preverbal children. [2003]

1.2.5.

In some patients (for example, patients with dementia, underlying chronic neurological disorders or learning disabilities) the pre-injury baseline GCS may be less than 15. Establish this where possible, and take it into account during assessment. [new 2014]

Initial assessment and care

1.2.6.

Initially assess adults who have sustained a head injury and manage their care according to clear principles and standard practice, as embodied in the:

• Advanced Trauma Life Support (ATLS) course/European Trauma course.
• International Trauma Life Support (ITLS) course.
• Pre-hospital Trauma Life Support (PHTLS) course.
• Advanced Trauma Nurse Course (ATNC).
• Trauma Nursing Core Course (TNCC).
• Joint Royal Colleges Ambulance Service Liaison Committee (JRCALC) Clinical Practice Guidelines for Head Trauma. [2003, amended 2007]

1.2.7.

Initially assess children who have sustained a head injury and manage their care according to clear principles outlined in the:

• Advanced Paediatric Life Support (APLS)/European Paediatric Life Support (EPLS) course.
• Pre-hospital Paediatric Life Support (PHPLS) course.
• Paediatric Education for Pre-hospital Professionals (PEPP) course. [2003, amended 2007]

1.2.8.

When administering immediate care, treat first the greatest threat to life and avoid further harm. (For advice on volume resuscitation in people with traumatic brain injury and haemorrhagic shock, see the NICE guideline on major trauma: assessment and initial management.) [2003]

1.2.9.

Attempt full cervical spine immobilisation for patients who have sustained a head injury and present with any of the following risk factors unless other factors prevent this:

• GCS less than 15 on initial assessment by the healthcare professional.
• Neck pain or tenderness.
• Focal neurological deficit.
• Paraesthesia in the extremities.
• Any other clinical suspicion of cervical spine injury. [2003, amended 2007]

1.2.10.

Maintain cervical spine immobilisation until full risk assessment including clinical assessment (and imaging if deemed necessary) indicates it is safe to remove the immobilisation device. [2003, amended 2007]

1.2.11.

Make standby calls to the destination emergency department for all patients with GCS 8 or less to ensure appropriately experienced professionals are available for their treatment and to prepare for imaging. [2003]

1.2.12.

Manage pain effectively because it can lead to a rise in intracranial pressure. Provide reassurance, splintage of limb fractures and catheterisation of a full bladder, where needed. [2007, amended 2014]

1.2.13.

Follow at all times best practice in paediatric coma observation and recording as detailed by the National Paediatric Neuroscience Benchmarking Group. [2003]

Transport to hospital

1.2.14.

Transport patients who have sustained a head injury directly to a hospital that has the resources to further resuscitate them and to investigate and initially manage multiple injuries. All acute hospitals receiving patients with head injury directly from an incident should have these resources, which should be appropriate for a patient’s age^[5]. [new 2014]

Training for ambulance crews

1.2.15.

Ambulance crews should be fully trained in the use of the adult and paediatric versions of the GCS and its derived score. [2003]

1.2.16.

Ambulance crews should be trained in the safeguarding of children and vulnerable adults and should document and verbally inform emergency department staff of any safeguarding concerns. [2003, amended 2014]

Involving the neurosurgical department

1.3.13.

Discuss with a neurosurgeon the care of all patients with new, surgically significant abnormalities on imaging. The definition of ‘surgically significant’ should be developed by local neurosurgical centres and agreed with referring hospitals, along with referral procedures. [2003, amended 2014]

1.3.14.

Regardless of imaging, other reasons for discussing a patient’s care plan with a neurosurgeon include:

• Persisting coma (GCS 8 or less) after initial resuscitation.
• Unexplained confusion which persists for more than 4 hours.
• Deterioration in GCS score after admission (greater attention should be paid to motor response deterioration).
• Progressive focal neurological signs.
• A seizure without full recovery.
• Definite or suspected penetrating injury.
• A cerebrospinal fluid leak. [2003]

Criteria for performing a CT head scan

Criteria for performing a CT cervical spine scan in adults

1.5.8.

For adults who have sustained a head injury and have any of the following risk factors, perform a CT cervical spine scan within 1 hour of the risk factor being identified:

• GCS less than 13 on initial assessment.
• The patient has been intubated.
• Plain X-rays are technically inadequate (for example, the desired view is unavailable).
• Plain X-rays are suspicious or definitely abnormal.
• A definitive diagnosis of cervical spine injury is needed urgently (for example, before surgery).
• The patient is having other body areas scanned for head injury or multi-region trauma.
• The patient is alert and stable, there is clinical suspicion of cervical spine injury and any of the following apply:

  -

  age 65 years or older

  -

  dangerous mechanism of injury (fall from a height of greater than 1 metre or 5 stairs; axial load to the head, for example, diving; high-speed motor vehicle collision; rollover motor accident; ejection from a motor vehicle; accident involving motorised recreational vehicles; bicycle collision)

  -

  focal peripheral neurological deficit

  -

  paraesthesia in the upper or lower limbs.

  A provisional written radiology report should be made available within 1 hour of the scan being performed. [new 2014]

1.5.9.

For adults who have sustained a head injury and have neck pain or tenderness but no indications for a CT cervical spine scan (see recommendation 1.5.8), perform 3-view cervical spine X-rays within 1 hour if either of these risk factors are identified:

• It is not considered safe to assess the range of movement in the neck (see recommendation 1.5.10).
• Safe assessment of range of neck movement shows that the patient cannot actively rotate their neck to 45 degrees to the left and right.

The X-rays should be reviewed by a clinician trained in their interpretation within 1 hour of being performed. [new 2014]

Criteria for performing a CT cervical spine scan in children

1.5.11.

For children who have sustained a head injury, perform a CT cervical spine scan only if any of the following apply (because of the increased risk to the thyroid gland from ionising radiation and the generally lower risk of significant spinal injury):

• GCS less than 13 on initial assessment.
• The patient has been intubated.
• Focal peripheral neurological signs.
• Paraesthesia in the upper or lower limbs.
• A definitive diagnosis of cervical spine injury is needed urgently (for example, before surgery).
• The patient is having other body areas scanned for head injury or multi-region trauma.
• There is strong clinical suspicion of injury despite normal X-rays.
• Plain X-rays are technically difficult or inadequate.
• Plain X-rays identify a significant bony injury.

The scan should be performed within 1 hour of the risk factor being identified. A provisional written radiology report should be made available within 1 hour of the scan being performed. [new 2014]

1.5.12.

For children who have sustained a head injury and have neck pain or tenderness but no indications for a CT cervical spine scan (see recommendation 1.5.11), perform 3-view cervical spine X-rays before assessing range of movement in the neck if either of these risk factors are identified:

• Dangerous mechanism of injury (that is, fall from a height of greater than 1 metre or 5 stairs; axial load to the head, for example, diving; high-speed motor vehicle collision; rollover motor accident; ejection from a motor vehicle; accident involving motorised recreational vehicles; bicycle collision).
• Safe assessment of range of movement in the neck is not possible (see recommendation 1.5.10).

The X-rays should be carried out within 1 hour of the risk factor being identified and reviewed by a clinician trained in their interpretation within 1 hour of being performed. [new 2014]

1.5.13.

If range of neck movement can be assessed safely (see recommendation 1.5.10) in a child who has sustained a head injury and has neck pain or tenderness but no indications for a CT cervical spine scan, perform 3-view cervical spine X-rays if the child cannot actively rotate their neck 45 degrees to the left and right. The X-rays should be carried out within 1 hour of this being identified and reviewed by a clinician trained in their interpretation within 1 hour of being performed. [new 2014]

1.5.14.

In children who can obey commands and open their mouths, attempt an odontoid peg view. [2003, amended 2014]

Transfer of adults

1.7.1.

Local guidelines on the transfer of patients with head injuries should be drawn up between the referring hospital trusts, the neuroscience unit and the local ambulance service, and should recognise that:

• transfer would benefit all patients with serious head injuries (GCS 8 or less) irrespective of the need for neurosurgery
• if transfer of those who do not require neurosurgery is not possible, ongoing liaison with the neuroscience unit over clinical management is essential. [2003, amended 2007]

1.7.2.

The possibility of occult extracranial injuries should be considered for adults with multiple injuries, and they should not be transferred to a service that is unable to deal with other aspects of trauma. [2007]

1.7.3.

There should be a designated consultant in the referring hospital with responsibility for establishing arrangements for the transfer of patients with head injuries to a neuroscience unit and another consultant at the neuroscience unit with responsibility for establishing arrangements for communication with referring hospitals and for receipt of patients transferred. [2003]

1.7.4.

Patients with head injuries requiring emergency transfer to a neuroscience unit should be accompanied by a doctor with appropriate training and experience in the transfer of patients with acute brain injury. They should be familiar with the pathophysiology of head injury, the drugs and equipment they will use and working in the confines of an ambulance (or helicopter if appropriate). They should have a dedicated and adequately trained assistant. They should be provided with appropriate clothing for the transfer, medical indemnity and personal accident insurance. Patients requiring non-emergency transfer should be accompanied by appropriate clinical staff. [2003, amended 2007]

1.7.5.

Provide the transfer team responsible for transferring a patient with a head injury with a means of communicating changes in the patient’s status with their base hospital and the neurosurgical unit during the transfer. [2003, amended 2014]

1.7.6.

Although it is understood that transfer is often urgent, complete the initial resuscitation and stabilisation of the patient and establish comprehensive monitoring before transfer to avoid complications during the journey. Do not transport a patient with persistent hypotension, despite resuscitation, until the cause of the hypotension has been identified and the patient stabilised. [2003, amended 2007]

1.7.7.

Intubate and ventilate all patients with GCS 8 or less requiring transfer to a neuroscience unit, and any patients with the indications detailed in recommendation 1.7.8. [2003]

1.7.8.

Intubate and ventilate the patient immediately in the following circumstances:

• Coma – not obeying commands, not speaking, not eye opening (that is, GCS 8 or less).
• Loss of protective laryngeal reflexes.
• Ventilatory insufficiency as judged by blood gases: hypoxaemia (PaO₂ < 13 kPa on oxygen) or hypercarbia (PaCO₂ > 6 kPa).
• Spontaneous hyperventilation causing PaCO₂ < 4 kPa.
• Irregular respirations. [2003, amended 2007]

1.7.9.

Use intubation and ventilation before the start of the journey in the following circumstances:

• Significantly deteriorating conscious level (1 or more points on the motor score), even if not coma.
• Unstable fractures of the facial skeleton.
• Copious bleeding into mouth (for example, from skull base fracture).
• Seizures. [2003, amended 2007]

1.7.10.

Ventilate an intubated patient with muscle relaxation and appropriate short-acting sedation and analgesia. Aim for a PaO₂ greater than 13 kPa, PaCO₂ 4.5 to 5.0 kPa unless there is clinical or radiological evidence of raised intracranial pressure, in which case more aggressive hyperventilation is justified. If hyperventilation is used, increase the inspired oxygen concentration. Maintain the mean arterial pressure at 80 mm Hg or more by infusion of fluid and vasopressors as indicated. In children, maintain blood pressure at a level appropriate for the child’s age. [2003, amended 2007]

1.7.11.

Education, training and audit are crucial to improving standards of transfer; appropriate time and funding for these activities should be provided. [2003]

1.7.12.

Give family members and carers as much access to the patient as is practical during transfer. If possible, give them an opportunity to discuss the reasons for transfer and how the transfer process works with a member of the healthcare team. [2003, amended 2014]

Transfer of children

1.7.13.

Recommendations 1.7.1–1.7.12 were written for adults, but apply these principles equally to children and infants, providing that the paediatric modification of the GCS is used. [2003]

1.7.14.

Service provision in the area of paediatric transfer to tertiary care should also follow the principles outlined in the National Service Framework for Paediatric Intensive Care. These do not conflict with the principles outlined in this section. [2003]

1.7.15.

The possibility of occult extracranial injuries should be considered for children with multiple injuries. Do not transfer them to a service that is unable to deal with other aspects of trauma. [2007]

1.7.16.

Transfer of a child or infant to a specialist neurosurgical unit should be undertaken by staff experienced in the transfer of critically ill children. [2003]

1.7.17.

Give family members and carers as much access to their child as is practical during transfer. If possible, give them an opportunity to discuss the reasons for transfer and how the transfer process works with a member of the healthcare team. [2003, amended 2014]

Observation of admitted patients

1.8.5.

In-hospital observation of patients with a head injury should only be conducted by professionals competent in the assessment of head injury. [2003]

1.8.6.

For patients admitted for head injury observation the minimum acceptable documented neurological observations are: GCS; pupil size and reactivity; limb movements; respiratory rate; heart rate; blood pressure; temperature; blood oxygen saturation. [2003]

1.8.7.

Perform and record observations on a half-hourly basis until GCS equal to 15 has been achieved. The minimum frequency of observations for patients with GCS equal to 15 should be as follows, starting after the initial assessment in the emergency department:

• Half-hourly for 2 hours.
• Then 1-hourly for 4 hours.
• Then 2-hourly thereafter. [2003]

1.8.8.

Should the patient with GCS equal to 15 deteriorate at any time after the initial 2-hour period, observations should revert to half-hourly and follow the original frequency schedule. [2003]

1.8.9.

Any of the following examples of neurological deterioration should prompt urgent reappraisal by the supervising doctor.

• Development of agitation or abnormal behaviour.
• A sustained (that is, for at least 30 minutes) drop of 1 point in GCS score (greater weight should be given to a drop of 1 point in the motor response score of the GCS).
• Any drop of 3 or more points in the eye-opening or verbal response scores of the GCS, or 2 or more points in the motor response score.
• Development of severe or increasing headache or persisting vomiting.
• New or evolving neurological symptoms or signs such as pupil inequality or asymmetry of limb or facial movement. [2003, amended 2007]

1.8.10.

To reduce inter-observer variability and unnecessary referrals, a second member of staff competent to perform observation should confirm deterioration before involving the supervising doctor. This confirmation should be carried out immediately. Where a confirmation cannot be performed immediately (for example, no staff member available to perform the second observation) the supervising doctor should be contacted without the confirmation being performed. [2003]

1.8.11.

If any of the changes noted in recommendation 1.8.9 are confirmed, an immediate CT scan should be considered, and the patient’s clinical condition re-assessed and managed appropriately. [2003, amended 2007]

1.8.12.

In the case of a patient who has had a normal CT scan but who has not achieved GCS equal to 15 after 24 hours’ observation, a further CT scan or MRI scanning should be considered and discussed with the radiology department. [2003]

Observation of infants and young children

1.8.13.

Observation of infants and young children (that is, aged under 5 years) is a difficult exercise and therefore should only be performed by units with staff experienced in the observation of infants and young children with a head injury. Infants and young children may be observed in normal paediatric observation settings, as long as staff have the appropriate experience. [2003]

Training in observation

1.8.14.

Medical, nursing and other staff caring for patients with head injury admitted for observation should all be capable of performing the observations listed in recommendations 1.8.6, 1.8.9 and 1.8.10. [2003]

1.8.15.

The acquisition and maintenance of observation and recording skills require dedicated training and this should be made available to all relevant staff. [2003]

1.8.16.

Specific training is required for the observation of infants and young children. [2003]

Discharge after observation

1.9.6.

Patients admitted after a head injury may be discharged after resolution of all significant symptoms and signs providing they have suitable supervision arrangements at home. [2003]

Discharge advice

1.9.7.

Give verbal and printed discharge advice to patients with any degree of head injury who are discharged from an emergency department or observation ward, and their families and carers. Follow recommendations in patient experience in adult NHS services [NICE clinical guideline 138] about providing information in an accessible format. [new 2014]

1.9.8.

Printed advice for patients, families and carers should be age-appropriate and include:

• Details of the nature and severity of the injury.
• Risk factors that mean patients need to return to the emergency department (see recommendations 1.1.4 and 1.1.5).
• A specification that a responsible adult should stay with the patient for the first 24 hours after their injury.
• Details about the recovery process, including the fact that some patients may appear to make a quick recovery but later experience difficulties or complications.
• Contact details of community and hospital services in case of delayed complications.
• Information about return to everyday activities, including school, work, sports and driving.
• Details of support organisations. [new 2014]

1.9.9.

Offer information and advice on alcohol or drug misuse to patients who presented to the emergency department with drug or alcohol intoxication when they are fit for discharge. [2003]

1.9.10.

Inform patients and their families and carers about the possibility of persistent or delayed symptoms following head injury and whom to contact if they experience ongoing problems. [new 2014]

1.9.11.

For all patients who have attended the emergency department with a head injury, write to their GP within 48 hours of discharge, giving details of clinical history and examination. This letter should also be shared with health visitors (for pre-school children) and school nurses (for school-age children). If appropriate, provide a copy of the letter for the patient and their family or carer. [new 2014]

Follow-up

1.9.12.

When a patient who has undergone imaging of the head and/or been admitted to hospital experiences persisting problems, ensure that there is an opportunity available for referral from primary care to an outpatient appointment with a professional trained in assessment and management of sequelae of brain injury (for example, clinical psychologist, neurologist, neurosurgeon, specialist in rehabilitation medicine). [2003]

Why this is important

The recommendations in this updated guideline for determining which patients need a CT head scan are based on the CHALICE clinical decision rule. CHALICE was derived in the UK but has yet to be validated, and limited evidence has been identified since the NICE clinical guideline was published in 2007. There is a need for a prospective validation and direct comparison of the 2014 NICE guideline and CHALICE, CATCH and PECARN clinical decision rules in a UK setting to determine diagnostic accuracy (sensitivity, specificity, and predictive values for intracranial injury and the need for neurosurgery) and cost effectiveness within the relevant population to which the NICE guideline is applied.

The study should be a prospective study with economic evaluation and should capture subgroups by age, separating out infants (under 2 years), children and young people (under 16 years) and adolescents (16–18 years). The results of such a study will confirm whether current practice is optimal and, if not, which would be the ideal clinical decision rule to implement in a UK population. To warrant recommendation of a different clinical decision rule and a consequent substantial change in practice, significant improvement in diagnostic accuracy must be demonstrated. This can only be done through such a prospective comparative validation study performed in our population.

Why this is important

Antiplatelet and anticoagulant drugs are widely and increasingly prescribed, and many patients presenting with a head injury to the emergency department are taking these drugs. While the majority of these drugs are prescribed in older patients they are also used in younger people. This guideline provides recommendations on performing CT head scans in patients on warfarin. However, limited evidence has been identified for patients using other antiplatelet or anticoagulant drugs within studies deriving or validating clinical decision rules for determining which patients need CT head scans. There is a particular paucity of evidence in determining whether they are at increased risk of intracranial haemorrhage.

A study with appropriate economic evaluation is needed to quantify the risk of taking these drugs over and above the risk factors included in an existing clinical decision rule. Antiplatelet and anticoagulant drugs should be studied as a predictor of intracranial injury and analysed within a multivariate analysis with other predictors (including the risk factors used in this guideline to determine when a CT head scan is needed). Univariable analyses of risk of intracranial injury in groups of head injury patients who are taking these agents and those who are not, and who have no other indications for CT head scan under current guidance would also be useful.

The GDG felt that, where possible, each drug should be considered separately, particularly aspirin and clopidogrel, and that the reference standard should include CT head scan and a follow-up period of sufficient duration to capture delayed bleeding, for example, at 7 days and 1 month. Analysis would benefit from subgroup results by age (children, adults and patients over 65 years). The GDG suggested reporting similar data used in the AHEAD study.

Why this is important

Circulating biomarkers, if validated, could provide a convenient and clinically applicable aid to the diagnosis of mild traumatic brain injury (TBI) – a ‘troponin for the brain’. If such biomarkers were sufficiently sensitive as well as specific for injury type (separating patients with traumatic axonal injury (TAI) from those with contusions), panels of biomarkers might not only help to determine which patients need neuroimaging but also allow us to devise rational, cost-effective pathways for neuroimaging – perhaps reserving primary use of advanced MRI for patients who have TAI as these lesions are undetectable on CT head scans. In addition, the availability of quantifiable biomarkers, scaled with the severity of injury, could help clinicians monitor the progression of brain injury in patients with more severe TBI, help stratify patients for trials and therapies, and provide significant prognostic information across all severities of TBI.

There is low-quality clinical effectiveness data for using the biomarker S100B to rule out significant intracranial injury in patients in the emergency department. Current evidence suggests that there is variation in the use of biomarker tests, including in the timing of testing, the concentration of biomarker used as a diagnostic cut-off, protocols used for sample transport and storage, and the equipment used for biomarker assays in laboratories. A diagnostic study (using randomised or consecutively selected patients) is needed to investigate the role of S100B in patients with selected head injury patterns.

The GDG also recognised the potential utility use of near-patient testing for biomarker tests to reduce the time from injury and blood sampling to test results. In addition, the GDG would welcome an additional outcome of 3-month follow-up of functional outcome/post-concussion symptoms alongside this study with appropriate economic evaluation. This research would provide UK-based evidence as to the potential benefit of biomarkers and any associated reduction in CT head scans and hospital admissions.

Why this is important

Although this recommendation was first made in 2007, the GDG felt that this is still an area of high priority for research and the question remains unanswered. The diagnosis of TBI is essentially a clinical one. However, although this approach provides the best current solution it can be imprecise, particularly in mild TBI where conventional imaging may be normal and cognitive abnormalities may be due to confounders such as pre-existing dementia, hypoxia or hypotension from associated injuries, alcohol or recreational drugs, and/or other conditions (such as post-traumatic stress disorder) which result in overlapping phenotypes (and possibly even imaging findings).

The availability of novel, objective methods of detecting brain injury provides an attractive means of better defining the presence of TBI in these contexts, with improvements in epidemiological precision. Perhaps more importantly, there is an increasing recognition that even mild TBI can result in prolonged cognitive and behavioural deficits, and the ability to identify patients at risk of these sequelae would aid clinical management, help determine which patients need novel therapeutic interventions, and refine resource allocation.

The techniques that have been explored in this regard include advanced neuroimaging with MRI, electroencephalographic (EEG) based diagnosis, and circulating biomarkers. The relative effectiveness and cost effectiveness of these techniques, individually and in combination, is not yet completely defined, and their role in contributing to a clinical decision rule that allows triage of patients to specific management pathways needs definition. A systematic review would be the first step in collating the available evidence in this area, followed by a rational application of available evidence, identification of key research questions that need to be addressed, and definition of the data collection needed in a derivation cohort study that allows these questions to be addressed.