Beyond Suspected Appendicitis: Ultrasonography in a Child With Multifocal Lymphadenitis and Suspected Cat‐Scratch Disease

Ultrasonography is particularly useful in children because it can be repeated without ionizing radiation and can be adapted to the clinical question during the examination. A 10-year-old boy with right lower quadrant pain, right leg pain, and a limp was referred with suspected acute appendicitis. A comprehensive diagnostic ultrasound examination of the abdomen demonstrated a normal appendix and an enlarged lymph node corresponding to the site of right lower quadrant tenderness. During the examination, conversation with the patient and his mother disclosed household cat ownership, frequent exposure to cat fleas, and multiple flea bites. The abdominal findings, exposure history, and pre-existing right leg symptoms were shared with the clinical team. At the physician's request, additional ultrasound evaluation of the right popliteal region demonstrated a second enlarged, tender lymph node. Superb microvascular imaging showed nonspecific vascular signals predominantly near the hila of both nodes. Serologic and molecular testing for Bartonella henselae was not performed; therefore, cat-scratch disease remained a clinical suspicion rather than a confirmed diagnosis. After azithromycin treatment, the symptoms improved and both lymph nodes decreased in size on follow-up ultrasonography. This case does not establish an ultrasonographic diagnosis of cat-scratch disease. Rather, it illustrates how ultrasonography provided anatomic correlates for symptoms at two sites, complemented the information available from clinical assessment alone, and supported noninvasive follow-up.