A diagnostic conundrum: case of acute appendiceal abscess mimicking multisystem inflammatory syndrome in children in a toddler

ABSTRACT

Case Report Patients with Multisystem Inflammatory Syndrome in Children (MIS-C) can commonly present with gastrointestinal symptoms of abdominal pain, vomiting, or diarrhea. These symptoms along with high fever and elevated inflammatory markers can often mask underlying gastrointestinal inflammation and lead to a diagnostic dilemma. Case Presentation We report a case of a 16-month-old with a history of exposure to SARS-Cov-2 virus, who presented with fever, cough, vomiting, and decreased activity. Her initial workup showed neutrophil-predominant leukocytosis with elevated CRP, ferritin, NTProBNP, and fibrinogen. Serology was positive for COVID-19 IgG antibodies, strongly favoring a diagnosis of MIS-C. Initial CT of the abdomen showed findings consistent with mild enteritis. Intravenous immunoglobulin was not administered as leukocytosis and all inflammatory markers except CRP improved during the course of her hospital stay with parenteral antibiotics, but she remained febrile with worsening abdominal symptoms. She then developed classic symptoms of peritonitis with tenderness and rigidity. Ultrasound of abdomen was inconclusive due to overlying bowel gas. Repeat CT of the abdomen showed multiple intra-abdominal abscesses with the largest rim enhancing lesion in the right lower quadrant. Her presentation was consistent with acute appendiceal abscess due to perforated appendix that improved with CT guided drainage and three weeks of intravenous antibiotics. She was then discharged and planned for an interval appendectomy after two weeks. [Figure presented] Conclusion(s) Symptoms of appendiceal abscess can mimic MIS-C. This case underscores the importance of considering appendicitis in the differential diagnosis in patients with MIS-C. Appendicitis can be missed in toddlers. Hence, clinical suspicion and repeat imaging is key for early diagnosis in this age group. CT Abdomen and Pelvis with intravenous and oral contrast showing findings of perforated, complicated acute appendicitis, with multiple abscesses. Copyright © 2023 Southern Society for Clinical Investigation.