Complicated Ulcerative Colitis in Pregnancy Due to Treatment Nonadherence: A Case Presenting As Suspected Appendicitis.

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon that requires continuous treatment. Treatment nonadherence, as well as pregnancy, can complicate disease management. This case describes a 23-year-old primigravida at 23 weeks' gestation with a history of UC who discontinued her treatment upon learning of her pregnancy. She presented with abdominal pain, bloody diarrhea, and systemic signs of infection. Imaging raised suspicion of appendicitis, and diagnostic laparoscopy revealed inflammatory involvement of the appendix and ascending colon, along with intra-abdominal fluid. Postoperatively, she was diagnosed with a severe UC flare and Clostridioides difficile infection. Despite antibiotic therapy, her condition progressed to fulminant colitis with bowel perforation, requiring an extended right hemicolectomy and ileostomy. Her course was further complicated by fetal demise, coagulopathy, aspiration pneumonia, hepatic congestion, and both arterial and venous thrombotic events, including an intracardiac thrombus. With multidisciplinary care, including anticoagulation and surgical wound management, she gradually improved and was discharged hemodynamically stable. This case highlights the high risk of adverse maternal and fetal outcomes when treatment is interrupted, the diagnostic complexity of the acute abdomen in this population, and the potential role of appendiceal involvement in disease severity.