[A case of idiopathic thrombocytopenic purpura development after total colectomy for ulcerative colitis]

Ulcerative colitis (UC) is known to be associated with extraintestinal manifestations. However, idiopathic thrombocytopenic purpura (ITP) has rarely been reported as one of the extraintestinal manifestations in UC. In most cases, ITP develops as an extraintestinal manifestation during the treatment for UC. After treatment with medications or colectomy, there is often a remission of UC and ITP. However, we experienced a case of ITP development after total colectomy for UC. An 83-year-old man was diagnosed as having UC and started treatment with medications. After 3 years, total colectomy and ileostomy were performed to prevent UC remission. Subsequently, no further treatment was provided. Two years later, he presented to the hematology department in our hospital with the chief complaint of thrombocytopenia and was diagnosed as having ITP. ITP was treated with steroids, and his platelet count increased to within the normal range. Immunological abnormalities may be involved in the development of extraintestinal manifestation, including UC-associated ITP. In previous reports, ITP was cured by colectomy for UC. In contrast, peripheral arthritis is a common extraintestinal manifestation of UC, and it is known that 75% of these patients develop or continue to experience such symptoms after colectomy. Some extraintestinal manifestations may equally persist after colectomy. However, the underlying mechanisms are poorly understood. Ileitis and small intestinal and duodenal inflammation are all known bowel complications associated with colectomy, and some immunological mechanisms have been suggested to be involved. Therefore, careful monitoring in these patients is necessary to detect any possibility of developing extraintestinal manifestations after colectomy. Further studies to examine the mechanisms underlying the immunological abnormality between UC and extraintestinal manifestations such as ITP are needed.