Objectives & Background Acute limp is a common presenting complaint in the paediatric emergency department. There are a number of possible causes of acute limp, ranging from the minor, such as traumatic injury, to more severe conditions, such as infection or malignancy. In young children, these causes are not always easily distinguished, even with the use of radiological imaging and laboratory investigations. With this pilot study, we aimed to develop an infrared thermographic imaging technique for use as a diagnostic aid in the diagnosis and monitoring of acute undifferentiated limp in young children. Therefore, the objectives of this study were to critically evaluate the effectiveness of thermal imaging in this context, whilst developing an appropriate protocol for an emergency environment.

Methods Following NHS ethics approval, 30 children were recruited from the Sheffield Children's Hospital ED. The participants were divided into groups based on diagnosis. Using an infrared camera, the lower limbs of the participants were imaged to record the skin surface temperature of both the affected side and unaffected side. Using predefined Regions of Interest (locations of thermographic measurement on the leg), any temperature difference between the two legs of each subject was recorded and the ability to isolate the specific region affected by injury was assessed.

Results In all Regions of Interest assessed, the median temperature reading for the affected side was higher than that of the unaffected side. The ability of infrared thermography to isolate the specific region affected was evident on an individual basis, with particular case studies showing promise. The small sample size recruited for each group meant that tests of significant difference need to be interpreted in this context and further research is required to form clinically meaningful conclusions.

Conclusion This pilot study has highlighted a number of potential avenues for future research into the use of thermographic imaging in an emergency setting. Repeating a similar study with a larger sample size will allow more credence to be given to the tests of significant difference. This study indicated that thermal imaging shows promise as an additional tool in the diagnosis and monitoring of acute undifferentiated limp in young children.