Abusive head trauma (AHT) is a leading cause of child traumatic death. AHT masquerading as accidental head trauma can be difficult to diagnose. Kent Hymel and his team at Penn State Health Children’s Hospital, in collaboration with researchers from the Pediatric Brain Injury Research Network (PediBIRN), carried out three multicentre research studies, involving over 900 young, acutely head-injured patients, to derive, validate, and implement a simple, effective, evidence-based screening tool for AHT. Their screening tool comes in the form of a four-variable clinical decision rule that guides doctors’ decisions regarding abuse evaluations in paediatric intensive care unit (PICU) settings, leading to fewer potential cases of missed abuse.
Abusive head trauma (AHT) is a form of child physical abuse and a leading cause of traumatic death in young children. Survivors of AHT often suffer severe disabilities. The findings of AHT are highly variable. In some cases abuse is obvious, but sometimes abused children present with findings that look like accidental trauma. AHT can therefore be difficult to diagnose. When head trauma is detected in infants and young children, determining whether it stems from abuse is of utmost importance, to prevent children from being returned to an abusive environment, where some have been re-injured or killed.
Because the findings of AHT overlap those of accidental head trauma, there is no gold standard for diagnosis. This is compounded by the fact that young children can’t communicate what has happened to them. Under-diagnosis is an obvious problem, but over-diagnosis can also lead to difficulties. Launching an unnecessary abuse evaluation increases parental stress, strains the doctor–parent relationship, exposes the patient to additional risks, prolongs his/her hospital stay, and increases healthcare costs. As Dr Hymel explains: ‘To protect young victims from further abuse, physicians must consider, recognise, evaluate, diagnose, and report suspected abuse. Lacking a gold standard, diagnosing AHT can be challenging.’
The PediBIRN screening tool for AHT separates children into higher and lower risk categories, and directs physicians to thoroughly evaluate their higher-risk patients for abuse. Its evidence-based guidance leads to more accurate and consistent decisions regarding abuse evaluations, thus reducing missed cases of AHT.
Derivation and validation of PediBIRN-4
To develop an effective screening tool for AHT, PediBIRN investigators completed two research studies. The first was an observational derivation study. Data from patients under three years with head trauma were collected from 14 different PICUs. Researchers identified a cluster of four clinical findings that could be combined to function as an effective clinical decision rule for AHT. The second study was an observational validation study. A new set of patients from different hospitals were assessed, to see whether the decision rule derived in the first study performed as predicted when applied as an AHT screening tool.
After analysing the data from both studies, it was confirmed that at least 96% of AHT patients presented with one or more of the new clinical decision rule’s four findings (Table 1). These included: acute respiratory compromise; bruising of the ears, neck, or torso; subdural hemorrhages or fluid collections that are bilateral or interhemispheric (bleeding or fluid overlying or between the two halves of the brain); and complex skull fractures (any skull fractures other than a single thin crack on one side of the skull).
Because each of these findings is routinely confirmed or excluded at or near the time of hospital admission, the new screening tool is easy to apply. The researchers called their new screening tool the PediBIRN-4. It directs that any child who presents with one or more of its four findings should be deemed a higher-risk patient and thoroughly evaluated for abuse. Its guidance must be used in conjunction with doctors’ clinical intuition and judgment, as there can be other factors that prompt or negate the need for an abuse evaluation.
Sensitivity and specificity
The PediBIRN-4 is highly sensitive at 96%, but it is not highly specific (Table 2). Specificity in both initial studies was around 40%. This means that 60% of higher-risk patients recommended for abuse evaluation were not abused. Stated more simply, to miss only 4% of cases, the PediBIRN-4 must ‘cast a wide net’, recommending abuse evaluation for many patients who were not abused. For diagnoses that create substantial risk of harm when missed, high sensitivity is more important than specificity.
The researchers’ first two studies confirmed that, applied accurately and consistently, the PediBIRN-4 AHT screening tool misses only 4% of cases. As a next step, the researchers wanted to evaluate how the screening tool would perform in active clinical settings. As Dr Hymel explains, ‘Doctors could choose to reject the screening tool or its recommendations. Therefore, the PediBIRN-4’s actual screening performance could be less than its potential performance’. Testing the PediBIRN-4 in a hospital setting was therefore the next step.
Applying PediBIRN-4 in a clinical setting
The PediBIRN investigators conducted a third study. Eight PICUs participated in a cluster randomised trial. Four of these were randomly chosen to be intervention sites, where strategies designed to encourage PediBiRN-4 application as an AHT screening tool were carried out over 32 months. PICU and child abuse doctors at these sites received online training that discussed the impact of missing AHT and instructions on how to apply the screening tool. They also received monthly emails that provided additional evidence supporting its value as a screening tool, attended local information-sharing sessions to discuss barriers to screening-tool application, and were provided access to an online ‘AHT probability calculator’. Use of the PediBIRN-4 was strongly encouraged, but physicians were not required to follow its recommendations. In the remaining four hospitals, these implementation strategies were not deployed, and physicians continued to treat and screen patients as they had done previously.
The results of the trial showed that the implementation strategies deployed at the four intervention sites led to changes in physicians’ AHT screening and evaluation practices. Specifically, physicians at these four hospitals increased the percentage of their higher-risk patients evaluated thoroughly for abuse (from 67% to 81%), whereas, at the four control sites, this percentage decreased (from 78% to 73%). These changes in clinical practice resulted in a significant divergence in potential cases of missed AHT at intervention sites compared to the control sites. The researchers estimated that 7% of AHT cases were still missed in the intervention hospitals over the course of the trial, which was higher than the potential outcome of only 4% from the observational studies. Most importantly though, this 7% was lower than the 13% estimate of missed AHT cases in the control hospitals. These results showed that, overall, physicians adopted the screening tool, and fewer AHT patients were likely missed.
Looking ahead for PediBIRN-4
Application of the PediBIRN-4 clinical decision rule as an AHT screening tool changed abuse-evaluation practices, resulting in fewer potential cases of missed AHT.
The next step is to promote and assess the adoption of the PediBIRN-4 as an AHT screening tool more broadly and in different clinical settings. Doing so could reduce stigma and stress for parents, reduce healthcare costs, and save the lives of children who suffer repeated abuse when returned to their abusive caregivers.
- Hymel, KP, Armijo-Garcia, V, et al, & Pediatric Brain Injury Research Network (PediBIRN) Investigators (2021) A Cluster Randomized Trial to Reduce Missed Abusive Head Trauma in Pediatric Intensive Care Settings. The Journal of Pediatrics, 236, 260–268.e3. 10.1016/j.jpeds.2021.03.055
- Hymel, KP, Armijo-Garcia, V, Foster, R, et al, & Pediatric Brain Injury Research Network (PediBIRN) Investigators (2014) Validation of a clinical prediction rule for pediatric abusive head trauma. Pediatrics, 134 (6), e1537–e1544. doi.org/10.1542/peds.2014-1329
- Hymel, KP, Willson, DF, Boos, SC, et al, & Pediatric Brain Injury Research Network (PediBIRN) Investigators (2013) Derivation of a clinical prediction rule for pediatric abusive head trauma. Pediatric Critical Care Medicine, 14 (2), 210–220. 10.1097/PCC.0b013e3182712b09
- Jenny, C, Hymel, CP, Ritzen, A, et al, (1999) Analysis of Missed Cases of Abusive Head Trauma. Journal of the American Medical Association, 281(7), 621–626. 10.1001/jama.281.7.621
Pediatric Brain Injury Research Network (PediBIRN) investigators conducted three multicentre research studies to minimise missed cases of abusive head trauma in children.
- Gerber Foundation
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
- Penn State University
- Penn State Health Children’s Hospital
J Albietz, V Armijo-Garcia, SC Boos, SJ Brown, A Bucher, KA Campbell, CL Carroll, A Chiesa, VM Chinchilli, LAM Christie, MS Dias, GA Edwards, D Escamilla-Padilla, K Even, AK Fingarson, TN Frazier, R Foster, JM Graf, S Haney, NS Harper, BE Herman, RA Higgerson, K Homa, P Hyden, R Isaac, N Jaimon, WA Karst, K Kaczor, NN Kissoon, L Kustka, A Laskey, N Livingston, DJ Lorenz, KL Makoroff, M Marinello C McKiernan, M Musick, SK Narang, J Noll, A Ornstein, MC Pierce, DA Pullin, LE Smith, KL Serrao, D Simms, A Sirotnak, M Stoiko, K Tieves, E Truemper, M Wang, K Weeks, DF Willson, MC Woosley
Kent P Hymel, MD is a board certified Child Abuse Paediatrician, a Professor of Paediatrics at Penn State College of Medicine, Medical Editor of the American Board of Pediatrics’ Subboard in Child Abuse Paediatrics, and Director of the Pediatric Brain Injury Research Network.
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