Cluster 195: abdominal perforation fistula gastrointestinal abscess intra history months prior ulcer 
Cluster 1298: abdominal diverticulitis abscess carcinomatosis obstruction intra gi coming gastrointestinal acute 
Cluster 1794: perforation gastrointestinal history fistula fistulae months ulceration bleeding gi prior 
Cluster 1805: abdominal including dose treatment disorders fistula study filter abscess ischemic 
Cluster 2037: abdominal bowel obstruction perforation abscess intra diverticulitis gastrointestinal carcinomatosis factors