Point-of-Care Ultrasound for Suspected Anorectal Infections in the Emergency Department

Background We aimed to evaluate the use of point-of-care ultrasound (POCUS) in the initial screening assessment and diagnosis of perirectal abscess and its impact on patient management in the emergency department (ED). Methods This is a retrospective review of patients who presented to two urban academic medical centers at an university in Arizona, United States, with clinical presentations concerning for anorectal infections over a three-year period. The institution's POCUS database was reviewed for examinations of the anorectal region. Electronic health records were reviewed for demographic characteristics, history, physical examination findings, ED course, additional imaging studies, consultations, impact of POCUS on patient care, and final disposition. Results A total of 27 cases were included in the final analysis. The most common presenting symptoms were pain (n=20, 74.1%), followed by swelling (n=9, 33.3%) and fever (n=6, 22.2%). The most common physical examination findings were tenderness to palpation (n=15, 55.6%), fluctuance (n=9, 33.3%), and presence of a palpable mass (n=8, 29.6%). The most common sonographic findings were fluid collection (mean=15.5, 57.4%) and cellulitis (mean=17, 63%). Fluid collections were further classified by location: Perirectal (n=5, 18.5%), perianal (n=10, 37%), and gluteal (n=6, 22.2%). The findings of the POCUS examinations were used in medical decision-making in 25 (92.6%) cases. Of the five patients with a final diagnosis of perirectal abscess, four (80%) were identified in the ED using POCUS. Of the 12 perianal abscesses diagnosed in the ED based on POCUS findings, 10 (83.3%) agreed with the final discharge diagnosis. Conclusion Point-of-care ultrasound has the potential to be a useful, noninvasive tool in the evaluation of anorectal complaints in the ED. In this retrospective review, POCUS findings were frequently documented in clinical decision-making and showed apparent concordance with final diagnoses in selected cases. While not a replacement for advanced imaging in all cases, it may serve as a valuable first-line modality to guide early management. Additional training and standardized imaging protocols may improve diagnostic performance. Larger prospective studies are needed to further define the diagnostic accuracy of POCUS and establish its role in the evaluation and management of anorectal complaints in the emergency setting.