一例 CAR-T 治疗后重型 COVID19 感染患者发生直肠坏死：病例报告

Coronavirus disease 2019 (COVID19) can cause gastrointestinal complications as well as respiratory tract disease. Coagulation abnormalities and thrombosis frequently occur in COVID19, especially in cases with severe clinical outcome. The relationship between gastrointestinal perforation and coagulopathy due to COVID19 remains unclear. CASE PRESENTATION: A 49-year-old female received Chimeric antigen receptor T (CAR-T) therapy for an early recurrence of diffuse large B-cell lymphoma (DLBCL) that was refractory to chemotherapy. She was diagnosed with cytokine release syndrome (CRS) because of a fever and oxygen desaturation, and administered tocilizumab. Forty days after completing CAR-T therapy, she was infected with COVID19 and transferred to our hospital. Her general condition worsened and she developed COVID19 pneumonia, and then steroid pulse therapy was started. While her respiratory condition improved, she experienced pain in the anal region and computed tomography (CT) revealed a rectal perforation. An emergency surgery was undertaken, and the lower rectum wall was found to be completely necrotic. Removal of the necrotic part of the rectum tissue, and drainage and lavage of necrotic tissue in the pelvic cavity were performed. The remaining rectum was resected with partial sigmoidectomy, but we could not make the anal stump closed. In addition, an end colostomy in the sigmoid colon was performed. Histopathological findings showed thromboses in the rectal mesentery veins. After the first surgery, the pelvic abscess cavity persisted and her high-grade fever continued. Reoperation was laparoscopically performed, and she underwent a resection of anal canal with residual necrotic rectal and mesorectal tissue, and a drainage of the pelvic abscess. After the reoperation, her general condition improved and CT showed that the abscess cavity had significantly improved.

Gastrointestinal perforation, especially rectal necrosis due to coagulopathy caused by severe COVID19 infection, is a rare but life-threatening complication. Physicians should have a high degree of clinical suspicion for timely diagnosis and management, and surgical intervention is necessary in cases of rectal necrosis.