Tehran University of Medical Sciences (TUMS) Academic Journal of Surgery 2423-3218 7 0 2024 09 10 1 7 Mohammadmahdi Abbasi Department of General Surgery, School of medicine, Tehran university of medical sciences, Tehran, Iran Ghavam Panahbar Department of General Surgery, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Aidin Yaghoobi Notash Department of General Surgery, School of Medicine, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran 2024 07 14 Background: Since 2019, the Covid-19 pandemic has led to the manufacturing of a wide range of different types of vaccines with different mechanisms of action. The data collected from various studies indicate that complications such as injection site pain, headache, fatigue, fever, and malaise are the most common side effects of Covid-19 vaccination. The most common site-specific complications in the gastrointestinal tract and nervous system in different studies were diarrhea, abdominal pain, nausea, vomiting, dizziness, headache, myalgia, peripheral neuropathy, and demyelinating diseases, respectively. In this study, we report a case that developed complications such as Guillain-Barré syndrome and Crohn’s colitis following Sinopharm/BBIBP COVID-19 vaccination. The course of Crohn’s disease (CD) was also complicated by CMV, and the patient developed fulminant colitis, which led to peritonitis. Case presentation: The patient was a 36-year-old Caucasian male who presented with severe generalized abdominal pain, nausea, vomiting, fever, dyspnea, and fatigue 4 days prior to admission. He mentioned a recent hospitalization due to bilateral ascending paraparesis, which was diagnosed as Guillain-Barré syndrome and treated with intravenous immunoglobulin. He also complained of watery diarrhea for a few weeks. The mentioned symptoms occurred following the injection of the Sinopharm/BBIBP COVID-19 vaccine. Due to the presence of pneumoperitoneum on chest radiography, the patient was transferred to the operating room with a diagnosis of generalized peritonitis and underwent midline laparotomy. On exploration of the abdominal cavity, the colon was perforated at two points: the sigmoid colon and the transverse colon. Signs of inflammation were observed around the perforated edges, but not elsewhere. The patient underwent an extended left hemicolectomy with end colostomy. The postoperative pathology report was consistent with CD, showing transmural chronic inflammation, deep fissuring ulcers, and cryptitis in the surgical specimen. Additionally, the immunohistochemical study for CMV was positive. Discussion: Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammatory disease with a wide spectrum of extraintestinal manifestations. Due to the incidence of IBD and Guillain-Barré syndrome in the mentioned patient following vaccination, there is a possibility of the same pathogenesis for both diseases. The incidence of Guillain-Barré syndrome as one of the extraintestinal complications of IBD has been reported in numerous studies as a result of the coexistence of both diseases. Also, according to the recent history of vaccination in a previously healthy individual, it is possible to justify the association of Guillain-Barré syndrome and IBD with the vaccine. So far, many studies have reported the development of Guillain-Barré syndrome following vaccination, but to the best of our knowledge, no studies have reported IBD following Covid-19 vaccination yet. Another issue in this patient was the complication of Crohn’s colitis with CMV. Despite the 7-8-fold higher incidence of CMV infection in patients with IBD, the role of CMV infection in Crohn’s colitis has not been determined. https://ajs.tums.ac.ir/index.php/ajs/article/view/268