Imaging in Paediatric Trauma – Guide to the RCR Guidelines. St.Emlyn’s

You’ve probably already seen that the Royal College of Radiologists this week published CEM-approved guidelines for imaging in paediatric trauma. The document itself is open access, isn’t actually that long and to the authors’ credit it’s relatively easy-to-read so you might want to stop reading this and start reading it instead :-).

So… What is a child anyway?

Not such an easy question to answer. The definition of “paediatric patients” used in this report covers those children under 16 years of age but most clinicians are aware of the broad spectrum of patients we see during adolescence and the startling variation in height, weight and maturity. In addition to physical and developmental differences, there is also clinical management variation for paediatric patients compared with their adult counterparts. The very grey nature of this patient cohort means that in order to make the guidelines work in practice this rather stark definition of “child” is accompanied by considerable flexibility in its subsequent recommendations.

Prior to publication, this guidance on trauma imaging protocols existed (from the Royal College of Radiologists in 2011). This was primarily an adult guideline with extrapolation to paediatric patients and while the original (general) protocols are still relevant, where there is discrepancy or confusion for patients under 16 years the new guidelines should be used.

Why are children special enough to need a separate report?

This isn’t another argument about why children aren’t just small adults – the report actually contains data which supports this assertion.

[DDET Patterns of Injury]

Thanks to the ongoing work of the Trauma Audit and Research Network (TARN) and their report on severe paediatric injury in England and Wales published in 2012 we know that injury patterns in children are different from those seen in adult patients.

TARN collects data about injured patients for the purposes of conducting research into injury patterns and outcomes, turning this into guidance in order to improve trauma care. The report tells us some interesting things about paediatric trauma patterns compared with adults.

• Under 16s made up just 6.21% of trauma patients in the data analysis from 2012 (2409/38778)
• The majority of paediatric trauma patients are seen first in mixed EDs (so paediatric-specific trauma protocols are not just for major trauma centres)

• In the subgroup of patients under 1 year of age, 42% had an isolated head injury (average across all groups 24%)
• In the subgroup of patients aged 1-5 years, 65% had an isolated extremity injury (average across all groups 29%)
• Isolated chest injury is unusual in children compared with adults

The report also shows us that in paediatric patients having CT scans, those presenting to a Major Trauma Centre (MTC) are less likely to have multiple body areas scanned than those presenting to a non-MTC. [/DDET]

[DDET Ionising Radiation in Kids]

Anyone who has worked in paediatrics knows we try to keep exposure to ionising radiation to a minimum due to the “real, significant and higher” cancer risks of CT imaging in younger age groups: the report calls this the ALARA principle:

Keep ionising radiation exposure As Low As Reasonably Achievable

This means that the routine use of adult protocols – arguably generous with CT scans – are not appropriate in children but until now paediatric-specific guidance has not been available.

The first question must be “does this child require imaging at all?”, the answer to which should come from clinical assessment by an experienced clinician. [/DDET]

Ultrasound Probes Out Then!

Well, not according to this report – “in the acute trauma setting there is currently no role for ultrasound outside of assisting in interventional procedures”.

The primary reason seems to be that at FAST will delay transfer to CT without providing additional information to that gleaned from CT. This is further qualified by references to FAST’s low NPV and poor sensitivity in paediatric trauma – but as far as I understood FAST the purpose was specificity not sensitivity anyway…

Well, What About MR Scan? It’s Radiation-Free!

Yes, MR scan is great for diagnosing spinal cord injury in kids. But unless you work in a completely amazing paediatric MTC where you can boast door-to-MR in 17mins for possible VP shunt blockage, access to MR scan can be… Challenging… Which the authors acknowledge. I have to say I’ve never tested the availability of trauma MR scan…

So How Should We Image Injured Children?

[DDET Head Injury]

CT is the primary investigation for paediatric head injury but not all head injured children require a CT brain: be guided by the NICE guidelines and remember that fulfilling the criteria for a CT brain does not indicate a CT cervical spine! [/DDET]

[DDET Cervical Spine]

Cervical spine injury is uncommon in paediatric patients.

Imaging of the cervical spine is not indicated on the basis of head injury alone: NICE has a separate algorithm extrapolated from adult data. Plain films may be indicated and if performed should include:

• Lateral c-spine from base of skull to C7/T1 junction
• AP c-spine from C2-T1. If you’ve read an early version of the report you might have noticed that it said C2-T10 but I have it on authority that this was a typo and will be corrected 🙂
• Adequate peg views if attainable, remembering that this may be difficult in younger children

In the presence of neurological findings to suggest cervical spine injury, MR scan is the imaging of choice. [/DDET]

[DDET Chest]

Blunt chest trauma – chest radiograph will detect pneumothorax, haemothorax, rib fractures, gross mediastinal abnormality and diaphragmatic injury: the need for further imaging will be informed by radiographic findings, mechanism of injury and clinical assessment

Penetrating chest trauma – contrast CT is the imaging of choice to detect occult vascular injury. The report provides some guidance about contrast dosing in appendix 2.

In paediatric patients with chest trauma CT is unlikely to change management if the patient is conscious and haemodynamically stable with a normal plain chest radiograph.  [/DDET]

[DDET Thoracic Spine]

In event of a high suspicion of thoracic spinal injury, plain films and MR scanning are advocated with CT only appropriate if MR scan is not acutely available. [/DDET]

[DDET Abdomen]

Where imaging is indicated, contrast CT is the modality of choice.

There is no mechanism of injury which, in isolation, mandates abdominal contrast CT: clinical assessment is important here too. Reduced GCS in presence of a head injury also does not mandate abdominal CT; abdominal injury is rare where neurological impairment exists without abdominal signs and symptoms.

The following mechanisms of injury and clinical findings have been shown to be associated with intra-abdominal injury so these may indicate a need for abdominal CT:

• Lap belt/handlebar injury
• Abdominal wall bruising
• Abdominal tenderness in conscious patient
• Abdominal distension
• Evidence of persisting hypovolaemia (e.g. persistent tachycardia)
• Blood via PR/NG routes

[/DDET]

[DDET Limbs]

Plain radiographs are first line, determined by clinical assessment although CT may be indicated for complex fractures. [/DDET]

[DDET Pelvis]

Pelvic fractures are rare in paediatric patients: screening XRs (as per the old “trauma series”) as routine are not indicated. Imaging is indicated only if there is clinical concern – and the presence of pelvic binder on arrival does not equal clinical concern!

Pelvic fractures are associated with multi-organ injury so if imaging is indicated, contrast CT of abdo and pelvis is the modality of choice. [/DDET]

Summary

Appendix 4 of the report includes a summary flowchart which is worth printing and sticking on your paediatric resuscitation area’s wall.