USA: Point-of-care ultrasonography has good diagnostic accuracy for the differentiation of abscesses from cellulitis, suggests a recent study in the journal Annals of Emergency Medicine. This, in turn, leads to correct change in management in about 10% of the cases.
Skin and soft tissue infections are common presentations in the emergency department. Previous studies have shown clinical examination alone to be unreliable in distinguishing between cellulitis and abscesses. A distinction between the two is important as each of them require difference treatments. Point-of-care ultrasonography has been increasingly studied as a tool to improve the diagnostic accuracy for these skin and soft tissue infections.
The primary objective of this systematic review by Michael Gottlieb, Department of Emergency Medicine, Rush University Medical Center, Chicago, IL, and colleagues, to evaluate the diagnostic accuracy of point-of-care ultrasonography for abscesses. Subgroup analyses are performed for adult versus pediatric patients and high suspicion versus clinically unclear cases. Secondary objectives include the percentage of correct versus incorrect changes in management and reduction in treatment failures because of point-of-care ultrasonography.
The researchers searched the online databases for studies assessing the diagnostic accuracy of point-of-care ultrasonography for the evaluation of skin and soft tissue abscesses, from inception to July 26, 2019. A total of 14 studies comprising 2,656 total patients were included.
Diagnostic accuracy was reported as sensitivity, specificity, positive likelihood ratio (LR+), and negative likelihood ratio (LR–), with 95% confidence intervals (CIs).
Key findings of the study include:
Point-of-care ultrasonography was 94.6% sensitive and 85.4% specific, with an LR+ of 6.5 and LR– of 0.06.
Among cases with a high pretest suspicion for abscess or cellulitis, point-of-care ultrasonography was 93.5% sensitive and 89.1% specific, with an LR+ of 8.6 and LR– of 0.07.
Among cases that were clinically unclear, point-of-care ultrasonography was 91.9% sensitive and 76.9% specific, with an LR+ of 4.0 and LR– of 0.11.
Among adults, point-of-care ultrasonography was 98.7% sensitive and 91.0% specific, with an LR+ of 10.9 and LR– of 0.01.
Among pediatric patients, point-of-care ultrasonography was 89.9% sensitive and 79.9% specific, with an LR+ of 4.5 and LR– of 0.13.
Point-of-care ultrasonography led to a correct change in management in 10.3% of cases and led to an incorrect change in management in 0.7% of cases.
"According to the current data, point-of-care ultrasonography has good diagnostic accuracy for differentiating abscesses from cellulitis and led to a correct change in management in 10% of cases. Future studies should determine the ideal training and image acquisition protocols," concluded the authors.
The study, "Point-of-Care Ultrasonography for the Diagnosis of Skin and Soft Tissue Abscesses: A Systematic Review and Meta-analysis," is published in the journal Annals of Emergency Medicine.
DOI: https://doi.org/10.1016/j.annemergmed.2020.01.004