Malignancy (commonly, colorectal cancer)
Diverticular disease
Compression from metastatic disease
Impaction
Strictures (IBD, chronic colonic ischemia)
Adhesions
Hernia
Toxic megacolon
Ischemic colitis
Adynamic ileus of the large and small bowel
Abdominal aortic aneurysm
Aortocaval fistula
Acute gastroenteritis
Aortoenteric fisulta
Appendicitis (early)
Bowel obstruction
Large bowel obstruction<unk> 
Small bowel obstruction
Malignant bowel obstruction
Bowel perforation
Gastroparesis
Diabetic ketoacidosis
Hernia
Inflammatory bowel disease
Mesenteric ischemia
Mesenteric vein thrombosis
Pancreatitis
Peritonitis
Sickle cell crisis
Spontaneous bacterial peritonitis
Volvulus
Aortocaval fistula
Large bowel obstruction<unk> 
Small bowel obstruction
Malignant bowel obstruction<unk> 
Mesenteric vein thrombosis
Ogilvie's syndrome
Malignancy 
Dressler's syndrome
Diverticular disease
Fitz-Hugh-Curtis syndrome
Compression from metastatic disease
Mallory-Weiss tear
Impaction