Answer: Pseudomembranous colitis
The CT images showed diffuse mucosal thickening ~1.5cm in thickness in large bowel especially at left side with increased adjacent fat attenuation and minimal fluid. That suggested a very extensive mucosal inflammation of large bowel, with rectum/ sigmoid being affected the most.
Colonoscopy was then performed, showing extensive inflammatory change over mucosal surface of whole large bowel, with thick fibrinous membrane covering raw surface. Some parts of surface beared polyp-like morphology. Colonic biopsy was taken for confirmation, whole stool was sent to ELIZA test for clostridium toxin A and B. Of course, both toxin result and biopsy results confirmed pseudomembranous colitis, and multi-drug resistant Acinetobacter was isolated from the biospy sample.
Metronidazole via nasogastric tube had been started before confirmation of disease. There was very drastic improvement of the clinical status, with all organ dysfunction subsided within one week. Since her response had been so impressive, no adjuvunt treatment for example IVIG was considered.
This case illustrated two facts
(1) Pseudomembranous colitis can come with relatively mild local symptoms
(2) Pseudomembranous colitis can cause septicemia with severe sequele