Appendicitis and its associated mortality and morbidity in infants up to 3 months of age: A systematic review

BACKGROUND AND AIMS: Although appendicitis is rare in young infants, the reported mortality is high. Primary aim of this systematic review was to provide updated insights in the mortality and morbidity (postoperative complications, Clavien‐Dindo grades I–IV) of appendicitis in infants ≤3 months of age. Secondary aims comprised the evaluation of patient characteristics, diagnostic work‐up, treatment strategies, comorbidity, and factors associated with poor outcome. METHODS: This systematic review was reported according to the PRISMA statement with a search performed in Pubmed, Embase and Web of Science (up to September 5th 2022). Original articles (published in English ≥1980) reporting on infants ≤3 months of age with appendicitis were included. Both patients with abdominal appendicitis and herniated appendicitis (such as Amyand's hernia) were considered. Data were provided descriptively. RESULTS: In total, 131 articles were included encompassing 242 cases after identification of 4294 records. Overall, 184 (76%) of the 242 patients had abdominal and 58 (24%) had herniated appendicitis. Two‐hundred (83%) of the patients were newborns (≤28 days) and 42 (17%) were infants between 29 days and ≤3 months of age. Either immediate, or after initial conservative treatment, 236 (98%) patients underwent surgical treatment. Some 168 (69%) patients had perforated appendicitis. Mortality was reported in 20 (8%) patients and morbidity in an additional 18 (8%). All fatal cases had abdominal appendicitis and fatal outcome was relatively more often reported in newborns, term patients, patients with relevant comorbidity, nonperforated appendicitis and those presented from home. CONCLUSION: Mortality was reported in 20 (8%) infants ≤3 months of age and additional morbidity in 18 (8%). All patients with fatal outcome had abdominal appendicitis. Several patient characteristics were relatively more often reported in infants with poor outcome and adequate monitoring, early recognition and prompt treatment may favour the outcome.