Endoscopic characterization of gastrointestinal manifestations in children with undifferentiated recurrent fever.

Background and study aims: Systemic autoinflammatory diseases are characterized by recurrent or chronic inflammation, and monogenic forms are increasingly defined. However, a group of patients without genetic diagnosis is called the syndrome of undifferentiated recurrent fever (SURF). This study analyzed the clinical and endoscopic features of patients with SURF presenting with gastrointestinal (GI) symptoms.

Patients and methods: Between 2019 and 2022, GI endoscopy were performed in patients with SURF who presented with GI symptoms. Clinical, genetic, laboratory, and endoscopy findings were analyzed.

Results: Fifteen patients were included in the study, eight (53.3 %) were girls. The mean age was 10.5 ± 5.80 years, and the median age at symptom onset was 4 (0.3-16) years. All patients experienced fever and abdominal pain. Thirteen patients (86.7 %) experienced diarrhea, 11 (73.3 %) reported myalgia, and 10 (66.7 %) had joint involvement. Lymphoid follicles in the terminal ileum mucosa were detected in 10 patients (66.7 %), and nodular lymphoid hyperplasia in the terminal ileum was the histopathological finding in 12 patients (80 %).

Conclusions: The current study found that patients with SURF experiencing gastrointestinal symptoms have excessive lymph node formation in the terminal ileal mucosa due to an exaggerated inflammatory response. This may be the cause of their GI symptoms.