POCUS Diagnosis of Bacterial Lymphadenitis Later Determined to be Cat Scratch Disease: A Unique Presentation and Review.

Acute lymphadenopathy has a wide range of possible etiologies, ranging from self-limiting viral infections to life-threatening malignancy. Point of care ultrasound (POCUS) can play a crucial role in identifying lymphadenopathy and ruling out other potential causes of soft tissue swelling, such as hernias, abscesses, and malignancies. Furthermore, POCUS enables the characterization of lymphadenopathy by evaluating the size, shape, echogenicity, and vascularity of the involved lymph nodes, thereby helping to identify the presence and extent of pathology. When performed at the time of initial presentation, POCUS can narrow the differential diagnosis and guide appropriate work-up and management. We present a case of a teenage male evaluated in the pediatric emergency department for acute bilateral inguinal swelling, in which POCUS identified lymphadenopathy and guided the evaluation of a presumed infectious process, ultimately determined to be caused by cat scratch disease.