Abdominal imaging and endoscopic characteristics of adult abdominal IgA vasculitis: a multicenter retrospective study

Background: IgA vasculitis (IgAV), previously known as Henoch-Schonlein purpura, is an IgA-mediated systemic small vessel vasculitis that tends to be more severe in adults than in children. Early diagnosis of IgAV involving the gastrointestinal tract remains difficult, especially in patients who present with gastrointestinal symptoms before purpura. This study aims to systematically analyze the abdominal imaging and endoscopic features of adult patients with abdominal IgAV, providing assistance to clinicians in the early recognition of this condition. Patients and Methods: This multicenter retrospective study was conducted in three large tertiary hospitals in China from January 2017 to January 2024. A total of 108 adult patients with abdominal IgAV, who had complete abdominal imaging and/or endoscopy results, were enrolled. The clinical manifestations, abdominal imaging findings, endoscopic characteristics, and serological indicators of the patients were analyzed. Results: The median age of the patients was 40 years (IQR: 26-55), with a male-to-female ratio of 2:1. Acute abdominal pain was the most common presenting symptom (100 patients, 92.59%). Bowel wall thickening was the most frequent finding on abdominal imaging (50/86 patients, 58.14%). Gastrointestinal endoscopy showed findings of congestion and erosion (32/67 patients, 47.76%), and erosion with ulcers (21/67 patients, 31.34%). Among patients with both imaging and endoscopic results, the duodenum (28/51 patients, 54.90%) and ileum (28/51 patients, 54.90%) were the most commonly affected sites. Laboratory findings revealed elevated white blood cell count (WBC), neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP), D-dimer and fibrinogen levels, along with decreased albumin level. Comparing patients with gastrointestinal symptoms versus purpura as the initial symptom, those with gastrointestinal symptoms had higher levels of WBC (p < 0.05) and NLR (p < 0.01). Conclusions: The most common symptom in adult abdominal IgAV patients is acute abdominal pain. In the early stage of the disease, most patients exhibit elevated levels of WBC, NLR, CRP, D-dimer, and fibrinogen, along with decreased albumin level. The duodenum and ileum are the most commonly affected sites. By integrating these findings, clinicians can identify abdominal IgAV patients earlier and more accurately.