Immigrant with stomach pain, distension, nausea, and fever · Dx?

A 34-year-old Eritrean man presented to the emergency department with complaints of diffuse abdominal pain and distention. He had emigrated to the United States 3 months earlier, following 5 years in a refugee camp in Ethiopia. Two weeks earlier, the patient sought care at his primary care clinic and was diagnosed with post-operative urinary retention and constipation following a recent hemorrhoidectomy. A Foley catheter was inserted and provided a short period of relief. Following the visit, however, his abdominal pain worsened. He also experienced increasing abdominal distention, a declining appetite, and persistent nausea. The patient said that he was unable to urinate and had not had a bowel movement in 6 days. He also described fevers, drenching night sweats, chills, and a 4-kg weight loss over 2 months.