Recurrent acute appendicitis after recovery from scrub typhus that was associated with hemophagocytic lymphohistiocytosis and other severe complications in children: a case report.

Background: With the advancement of diagnostic technology, diagnosing and treating scrub typhus (ST) has become easier, and ST is currently commonly associated with various complications. At present, there is no report of a recurrent acute appendicitis requiring surgical resection after the successful treatment of ST with severe complications, such as hemophagocytic lymphohistiocytosis (HLH), in children during follow-up. Case presentation: We report the case of a 10-year-old girl from Sichuan, China, who had fever, abdominal pain, and lethargy. Abdominal computed tomography (CT) scans indicated appendicitis, and the surgeons indicated that surgery was unnecessary. She was then admitted to the Pediatric Intensive Care Unit (PICU) and rapidly developed severe complications (HLH, septic shock, acute kidney injury, acute respiratory distress syndrome, and disseminated intravascular coagulation) within 24 h after admission. She was diagnosed with ST by metagenomics next-generation sequencing (mNGS). After treatment with doxycycline, dexamethasone (DEX), and etoposide, as well as advanced life support, she recovered after 25 days of hospitalization and was discharged. However, she underwent a laparoscopic appendectomy due to abdominal pain a month after a reduction in the dose of DEX. The appendix was 6 cm long and 1.0 cm in diameter, and the pathological report suggested simple acute appendicitis. After 11 months of follow-up, that is, 10 months after the appendectomy, all indicators were normal and no similar abdominal pain recurred. Conclusion: Pediatricians should be vigilant and should initiate HLH treatment protocols when ST-associated HLH occurs with other severe complications. Acute appendicitis may not only occur during the course of ST, but may also occur after successful treatment for ST.