狼疮肠系膜血管炎（LMV）作为儿童系统性红斑狼疮（SLE）首发起病的情况非常罕见，临床表现为腹痛、呕吐、腹泻等非特异性症状，极易误诊。患儿，男，13岁，因腹痛伴呕吐2天就诊。入院体检示全腹肌紧张，肠鸣音减弱。辅助检查血小板30×10⁹/L，抗核抗体1:320阳性，抗心磷脂抗体IgM阳性，C3和C4降低，Coomb's试验弱阳性，24小时尿蛋白1.18 g；腹部CT示小肠肠壁明显增厚、水肿（靶征）。明确诊断为SLE、LMV，予甲基泼尼松龙60 mg及羟氯喹治疗，腹痛好转，但血小板进行性下降，先后予环孢素、甲基泼尼松龙冲击治疗血小板仍下降，予利妥昔单抗治疗后血小板逐渐升高，后续予贝利尤单抗治疗，病情平稳后出院。LMV可为SLE首发表现，腹部CT对LMV确诊有重要价值。糖皮质激素可有效减轻病情，但LMV易复发，环磷酰胺冲击及利妥昔单抗治疗可能对复发患者效果好。

Lupus mesenteric vasculitis (LMV) as the first onset of systemic lupus erythematosus (SLE) in children is very rare. The clinical manifestations are abdominal pain, vomiting, diarrhea and other non-specific symptoms, which are easy to be misdiagnosed. A 13-year-old boy was admitted to Shanghai Children's Hospital who presented with abdominal pain and vomiting for 2 days. Physical examination on admission found that the child's abdominal muscles were tense and bowel sounds were weakened. Laboratory tests showed platelets of 30×10⁹/L, positive antinuclear antibody (1:320), positive anticardiolipin antibody IgM, decreased complement C3 and C4, weakly positive Coomb's test, and 24-hour urinary protein of 1.18 g. Abdominal CT showed significantly thickened and edema intestinal wall. After the patient was diagnosed with SLE and LMV, he was treated with 60 mg of methylprednisolone and hydroxychloroquine. The abdominal pain improved, but the platelet gradually decreased. After high-dose methylprednisolone and cyclosporine pulse therapy, platelet was still decreasing. After rituximab treatment, the patient's platelets gradually increased, and he was subsequently treated with belimumab. He was discharged after his condition stabilized. LMV can be the first manifestation of SLE. Abdominal CT has an important value in the diagnosis of LMV. Glucocorticoids can effectively alleviate the disease, but LMV is prone to relapse. Cyclophosphamide pulse therapy and rituximab may be effective in patients with relapse.