Article Text
Abstract
With trauma being a leading cause of death for children, identifying all sustained injuries remains a priority for clinicians, and imaging is a key diagnostic tool to ensure that is achieved. However, children have a greater risk of detrimental effects of ionising radiation than adults. Clinicians therefore have to balance limiting their patients’ radiation exposure to ‘as low as reasonably achievable’ with the need for diagnostic accuracy. But what is ‘reasonable’ in major trauma can be confusing. This article aims to clarify the current guidance on which body part to scan and when in paediatric major trauma.
- accident & emergency
- imaging
- paediatric practice
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With trauma being a leading cause of death for children, identifying all clinically significant injuries remains a priority for clinicians, and imaging is a key diagnostic tool to ensure that is achieved. However, children have a greater risk of detrimental effects of ionising radiation than adults as they are more radiation sensitive and have a longer life expectancy in which this damage may be expressed. Clinicians therefore have to balance limiting their patients’ radiation exposure to ‘as low as reasonably achievable’ (also known as the ALARA, as low as reasonably achievable, principle), with the need for diagnostic accuracy. But what is ‘reasonable’ in major trauma can be confusing. Full body CT for every patient will of course identify more injuries, but how many of these will be clinically significant? Restricting imaging may reduce the longer term risk of radiation but at the cost of possible missed injuries. This article aims to clarify the current guidance on which body part to scan and when in paediatric major trauma in order to optimise identification of those injuries requiring treatment and minimise ionising radiation.
What constitutes major trauma?
The definition of major trauma is an injury severity score (ISS) of over 15. The ISS scores the injuries received by a patient, so it may be difficult to correctly predict major trauma before a complete assessment. For this reason, triage tools are used to help identify these patients and different tools exist for different trusts and prehospital networks. Essentially, they all rely on a set of indicators that include clinical signs, observations and mechanism of injury. Attached is an example from Alder Hey Hospital in Liverpool, used with their permission.
The Trauma Audit and Research Network advise that trauma systems need to be refocused to account for the way non-accidental injury (NAI) presents, as these children are currently being missed by the standard in-hospital and prehospital triage tools. This is especially important when one considers that suspected NAI accounts for about 10% of all major trauma in childhood, with the peak incidence being the first 3 months of life.1
Early communication with radiology
When assessing a child with major trauma discussion with a radiologist prior to organising any CT should be mandatory, as review of plain X-rays (eg, of the chest or neck) by a specialist may do away with the need for further ionising radiation.
If CT is deemed necessary, appropriate dose reduction procedures should be in place, and avoidance of the lens should be optimised.
Investigation by body type
Head injury
The National Institute of Clinical Excellence (NICE) has published guidance that is nationally accepted2 (figure 1). This aims to appropriately identify intracranial injury while minimising the frequency of head CT. While no guidance is perfect, this gives reasonable clarity to the physician dealing with paediatric trauma. There is one area of controversy, however, and that is isolated vomiting. In younger children with vomiting and no other indication for CT after a head injury, it would be prudent to ask for a senior review before committing the child to radiation. Children vomit for many different reasons including intercurrent illness, air-swallowing during crying, pain and anxiety. Isolated vomiting is unlikely to be due to a significant head injury and a period of observation would be a safe option.3 It should be remembered, however, that in adults isolated vomiting is more likely to be significant and so CT should be considered in vomiting head-injured teenagers3 (who are also at less risk from ionising radiation).
C-spine injury and whole spine injury
MR is the investigation of choice for suspected spinal injuries, but this may be difficult to obtain in the emergency situation, particularly in a critically ill child.
NICE guidance is available to help decide whether CT or plain film may be of use, but with two different guidelines available, management is far from clear.
Clinical Guideline 176 (CG176)2 (see figure 2), published in 2014 but last updated September 2019, suggests avoidance of CT (due to the risk of irradiating the thyroid) unless any of the following are present:
GCS, Glasgow Coma Scale,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 (eg, before surgery).
The patient is having other body areas scanned for head injury or multiregion 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.
Children with neck pain or tenderness who do not require a CT scan following these recommendations should, according to CG176, have three-view c-spine X-rays before an assessment of range of movement if there has been a dangerous mechanism of injury. Their definition of this includes a fall from a height of greater than 1 metre or five stairs; axial load to the head; high-speed motor vehicle collision; rollover motor accident; ejection from a motor vehicle; accident involving motorised recreational vehicles; and bicycle collision. Guidance must be taken as such, with consideration given to the particular mechanism of injury of each individual case. Some are not as dangerous as they first appear, and vice versa. For example, many falls downstairs by toddlers are actually a series of small, low-impact falls rather than one large impact, and some bicycle collisions may be of very low velocity. The full three views may also be difficult to obtain, as an odontoid peg view requires a compliant child to fully open their mouth.
NICE Guideline 41 (NG41)4 also gives advice for imaging the spine. It suggests MRI for children in whom the Canadian C-Spine Rule suggests imaging is required; however, the Canadian C-Spine Rule was validated in a population over the age of 16 years and cites age under 16 years as being an exclusion factor.5 NG41 also suggests MRI for those in whom clinical assessment suggests cervical spinal cord or column injury, although it does not give guidance as to what those clinical findings may be. Plain X-rays are suggested for those who do not fulfil criteria for an MRI but in whom clinical suspicion remains. This does not make the decision on imaging modality particularly easy. NG41 closes its guidance on imaging the cervical spine in children by referring clinicians dealing with children with a head injury and suspected cervical spine injury to CG176. So in summary, CG176 seems to be the most pragmatic guidance to follow in the acute setting.
For the rest of the spine, clinical assessment should guide whether further imaging is needed. Specifically, midline tenderness, focal tenderness and neurological signs will necessitate further investigation. Plain X-ray is usually the primary investigation,6 but targeted CT may be needed, after discussion with a radiologist, for further assessment. The lumbar spine will be visible in the CT of the abdomen and pelvis if this was done for other reasons. If the child has neurological signs, then ideally MR should be the primary imaging modality.6
Chest
Plain chest X-ray is a quick and easy imaging strategy for early detection of important injuries in a child with major trauma. Further imaging should then be guided by the result of the X-ray, the patient’s condition and the mechanism of injury.
The Royal College of Radiologist (RCR) advocate that CT should not be needed in a clinically stable child, with a normal level of consciousness and a normal chest X-ray6 (figure 3).
Penetrating trauma is different, as it can lead to vascular injury, which may be difficult to identify on plain X-ray, and therefore, in this instance, contrast CT would be indicated.
Clinicians experienced in extended focused assessment with sonography in trauma (FAST or eFAST) may be able to use this to detect a pneumothorax, haemothorax or pericardial effusion at the bedside.
Abdomen and pelvis
According to the RCR’s Guidance, there is no role for ultrasound in paediatric trauma except to assist in interventional procedures.6 FAST scan is therefore discouraged, especially if it would cause a delay in transfer to CT.
Evidence currently shows that FAST performs poorly to rule out blunt intra-abdominal injury in paediatric trauma.7 8 In the haemodynamically stable patient, performing a FAST scan prior to CT has not been shown to improve patient outcomes.
According to RCR, the need to CT an abdomen should be based on examination and history. There are no mechanisms of injury that make abdominal CT mandatory. A low GCS from isolated head injury alone is also not enough for a CT of the abdomen.
The clinical variables below are described to be associated with an increased need for abdominal CT:
Lap belt or handle bar injuries.
Abdominal wall ecchymosis.
Abdominal tenderness in a conscious patient.
Abdominal distension.
Clinical evidence of persistent hypovolaemia.
Blood from the rectum or nasogastric tube.
The Pediatric Emergency Care Applied Research Network’s9 prediction rule to identify children with blunt abdominal trauma who are very low risk for clinically important intra-abdominal injuries performed well in reviews with sensitivities of up to 99%.10
The rule looks at seven variables that, if all are present, can reliably obviate the need for abdominal CT10 (figure 4).
CT abdomen and pelvis will also identify pelvic injuries, although it must be noted that pelvic fractures are not common in children, and a plain X-ray of the pelvis is not mandatory in all major trauma. Due to the high risk of organ injuries associated with pelvic bony injuries, CT remains the imaging modality of choice when a fracture is suspected.6
Trauma CT in children
Whole body CT in children is strongly discouraged in both the RCR guidance and the NICE guidance.11 After these were published, the Royal College of Emergency Medicine released a statement to advise clinicians that special consideration should be given to whole body CT, especially outside paediatric centres, in circumstances where patients have been exposed to high mechanisms of injury, particularly with trauma to more than one body region, where there are signs of shock, distracting injuries or a low GCS. This statement also reminds clinicians that whole body CT should not be a routine investigation but guided by due consideration of the risks and benefits entailed.12
Conclusion
Paediatric major trauma is rare but remains the number one cause of morbidity and mortality in children. Therefore, getting it right every time for every patient is paramount, and balancing the need for further investigation with the risk of radiation is important. Available guidance can support clinicians in deciding what is best for their patients; however, there is no single best answer, and due consideration must be given to the individual clinical scenario including mechanism of injury, examination findings and resultant clinical suspicion of risk.
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Footnotes
Twitter @nikkiabela
Contributors The primary author, NA, has written the main stem of the article and the infographics, with the second author, EH, completing the piece, reviewing, editing and adding to the article.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Commissioned; externally peer reviewed.
Data availability statement There are no data in this work.
Author note The authors are blog editors for RCEMLearning and have created a blog to complement this article on the website www.rcemlearning.co.uk