[Anti-neutrophil cytoplasmic antibody-associated vasculitis with gastrointestinal bleeding as the main symptom: a case report and literature review].

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) has a wide range of symptoms, and it is difficult for clinicians to make a quick and correct diagnosis. On November 11, 2021, a 36-year-old male patient with AAV was admitted to the emergency and critical care department of Yichang Central People's Hospital. He was admitted to the emergency intensive care unit (EICU) with gastrointestinal symptoms (abdominal pain, black stool) as the main physical signs, and was initially diagnosed as AAV with gastrointestinal hemorrhage (GIH). No bleeding point was found after repeated gastroscopy and colonoscopy. Abdominal emission CT (ECT) showed diffuse hemorrhage in the ileum, ascending colon and transverse colon. Multi-disciplinary consultation in the whole hospital considered the diffuse hemorrhage caused by small vascular lesions in the digestive tract caused by AAV. Pulse therapy with methylprednisolone 1 000 mg/d and immunosuppressive therapy with cyclophosphamide (CTX) 0.2 g/d were administered. The patient's symptoms quickly relieved and transferred out of the EICU. After 17 days of treatment, the patient finally died of massive gastrointestinal bleeding. A systematic review of relevant literatures combined with the case diagnosis and treatment process found that only a minority of AAV patients present with gastrointestinal symptoms as their first symptoms, and patients with GIH were very rare. Such patients had a poor prognosis. This patient delayed the use of induced remission and immunosuppressive agents due to the treatment of gastrointestinal bleeding, which may be the main cause of life-threatening GIH secondary to AAV. Gastrointestinal bleeding is a rare and fatal complication of vasculitis. Timely and effective induction and remission treatment is the key to survival. Whether patients should receive maintenance therapy, the duration of maintenance therapy, and the search for markers of disease diagnosis and treatment response are directions and challenges for further research.