Ings, A. Head injury – who to scan?, Don't Forget the Bubbles, 2013. Available at:
Kids come into emergency EVERY day with head injury. In many cases imaging decisions are simple. Especially when the child rolled off the bed, cried straight away & is now tearing up the ED – BUT plenty of cases present a diagnostic dilemma for physicians. This summary of recent guidelines aims to help with imaging decisions.
Head injury (HI) in children is very common
- Accounts for ~ 3.4% of all ED presentations in the UK
- HI still a leading cause of paediatric mortality & disability
- Only 4-7% presenting with ‘minor’ HI have visible brain injury on CT
- Only 0.5% require neurosurgery
BUT – we need to identify this group rapidly
CT is the standard imaging & provides rapid diagnosis of intracranial injuries and guides subsequent neurosurgical management BUT – carries significant risks & costs
- Difficult to quantify, but estimated incidence of lethal malignancy from a paediatric CT brain ~ 1 in 1000 to 1 in 5000
- There are additional sedation risks in young children
CT rates are increasing. An estimated million children each year in the US are scanned unnecessarily! Despite this, a small but important number of intracranial bleeds are missed at first ED presentation.
How do we decide who to scan..?
Several Clinical Decision Rules (CDRs) have been developed to identify which children are at high-risk of intracranial injury & require CT. Recent review articles have identified 3 high-quality CDRs.
Children’s Head Injury Algorithm for the Prediction of Important Clinical Events – CHALICE (2006) (UK guideline incorporated in NICE guideline)
Prediction Rule for Clinically-important Traumatic Brain Injury from the Pediatric Emergency Care Applied Research Network – PECARN (2009) (US guideline)
Canadian assessment of Tomography for childhood head injury rule – CATCH (2010)
Children’s Head Injury Algorithm for the Prediction of Important Clinical Events – CHALICE rule (Arch Dis Child 2006, 91: 885-891)
- Several high-quality CDRs exist for adult head injury
- CHALICE was the first paediatric rule to identify children requiring CT
- Derived z highly sensitve rule from a large, multicentre UK study
- 22 772 children recruited over 2½ years
- Outcome measures – ‘clinically significant head injury’
- Defined as: death; need for neurosurgery; or abnormal CT scan
- Defined CT abnormality as any acute traumatic intracranial pathology, haematoma, contusion, cerebral oedema, and depressed skull fractures
- Non-depressed (linear) skull fracture not considered significant
- 281 children had abnormal CT (1.2%)
- 137 had neurosurgery (0.6%) & 15 died (0.07%)
The CHALICE rule was derived with a sensitivity of 98%, Specificity 87% to predict clinically significant head injury.
So what is the rule? 3 parts to CHALICE – History, examination & mechanism…
- If child does not meet any criteria they are low-risk for intracranial injury
- But CT is required if any of the following criteria are present….
The trouble with CHALICE – highly sensitive but not specific
- A recent Australian study found implementation of CHALICE may potentially more than double CT rate
- With only a very small increase in detection of CT abnormalities
- And none of those requiring intervention
‘Identification of children at very low risk of clinically-important brain injuries after head trauma’. Kuppermann et al. Lancet. 2009; 374 (9696):1160-70.
- Aimed to identify children at low risk of clinically-important traumatic brain injury (ciTBI) who may not need CT
- Prospective cohort across 25 EDs – 42,412 children
- Included HI presenting within 24h, with GCS 14-15
- Excluded trivial injuries (falls from standing height, no sign of head trauma other than laceration/abrasion)
- Excluded GCS < 14, as these have ~ 20% risk of ciTBI & CT is not controversial – risk far outweighs radiation risk
- CT scans obtained at ED physician’s discretion
- Pre-verbal (< 2 y) & verbal (> 2 y) analysed separately
Decision Rules for Avoiding CT in Children with Head Trauma
< 2 years
> 2 years
|Normal mental status||Normal mental status|
|No scalp haematoma except frontal||No LOC|
|LOC < 5 seconds||No vomiting|
|Non-severe injury mechanism*||Non-severe injury mechanism*|
|No palpable skull #||No signs of basilar skull #|
|Normal behaviour||No severe headache|
|*Severe mechanism defined as MVA with patient ejection, death of a passenger, rollover; pedestrian or cyclist without helmet struck by motorised vehicle; fall > 1.5m for children (> 2 years), & fall > 0.9m for < 2 years; or head struck by high impact object|
- Derived & validated age-specific prediction rules for ciTBI
- Derivation group (33785) & validation groups (8627)
- 14969/42412 (35%) had CT scans
- 376 (0.9%) had ciTBI
- 60 (0.1%) had neurosurgery
Good points about PECARN –
- Large sample size with validated rules
- Rules are simple & intuitive
- If none of the 6 predictors the risk of ciTBI was <0.02%
- Multicentre prospective cohort across 10 Canadian Paediatric hopsitals
- 3866 with ‘minor’ head injuries enrolled – GCS 13-15, AND
- Persistent vomiting
- Physicians completed a standardised assessment from before CT
- Main outcome measures: need for neurosurgery & brain injury on CT
- Developed a highly sensitive CDR by analysing variables strongly associated with these outcome measures
- 159/3866 (4.1%) had brain injury on CT
- 24 (0.6%) had neurosurgery
CT brain is only required for children with minor* HI and any one of the following…
- GCS < 15 at 2h after injury
- Suspected open/depressed skull #
- History of worsening headache
- Irritability on examination
- Any sign of basal skull # (Battles sign, CSF leak, racoon eyes)
- Large, boggy scalp haematoma
- Dangerous mechanism (MVA, fall from height > 3 feet or 5 stairs, fall from bicycle without helmet)
*Minor head injury – defined as HI within past 24 hours associated with witnessed LOC, definite amnesia, witnessed disorientation, persistent vomiting (more than one episode), or persistent irritability in a child <2 years) in a patient GCS 13-15.
With all these rules & guidelines – what are we doing now?
Recent Australian study (Lockie et al. EMA. (2013) 25, 75-82.) compared triggers for head CT reported by senior paediatric ED physicians at PREDICT (Paediatric Research in Emergency Departments International Collaborative) sites in Australia & NZ.
They reported a high variability between sites & physician, and despite physicians being aware of the recommendations for CT in CATCH, CHALICE & PECARN CDRs, often did not follow these.
PREDICT sites in Australasia are currently looking at head injury guidelines and aiming to give a more definitive answer in the near future…..
Lockie F et al. Triggers for head computed tomography following paediatric head injury: Comparison of physicians’ reported practice and clinical decision. Emergency Medicine Australasia. (2013) 25, 75-82.
Crowe L et al. Application of the CHALICE clinical prediction rule for intracranial injury in children outside the UK: impact on head CT rate.Arch Dis Child. 2010 Dec;95(12):1017-22.
Comparing CATCH, CHALICE and PECARN clinical decision rules for paediatric head injuries.Lyttle MD, Crowe L, Oakley E, Dunning J, Babl FE.Emerg Med J. 2012 Oct; 29(10):785-94.
Should a head-injured child receive a head CT scan? A systematic review of clinical prediction rules.Maguire JL, Boutis K, Uleryk EM, Laupacis A, Parkin PC.Pediatrics. 2009 Jul; 124(1):e145-54.
Derivation of the children’s head injury algorithm for the prediction of important clinical events decision rule for head injury in children.Dunning J, Daly JP, Lomas JP, Lecky F, Batchelor J, Mackway-Jones K, Children’s head injury algorithm for the prediction of important clinical events study group.Arch Dis Child. 2006 Nov; 91(11):885-91.
CATCH: a clinical decision rule for the use of computed tomography in children with minor head injury.Osmond MH, Klassen TP, Wells GA, Correll R, Jarvis A, Joubert G, Bailey B, Chauvin-Kimoff L, Pusic M, McConnell D, et al.CMAJ. 2010 Mar 9; 182(4):341-8. Epub 2010 Feb 8.
Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study.Kuppermann N, Holmes JF, Dayan PS, Hoyle JD Jr, Atabaki SM, Holubkov R, Nadel FM, Monroe D, Stanley RM, Borgialli DA, et al.Lancet. 2009 Oct 3; 374(9696):1160-70.