Infection frequently triggers thrombotic microangiopathy in patients with preexisting risk factors: a single-institution experience.

Thrombotic microangiopathies are rare conditions characterized by microangiopathic hemolytic anemia, microthrombi, and multiorgan insult. The disorders, which include hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, are often acute and life threatening. We report a retrospective analysis of 65 patients presenting to our institution from 1997 to 2008 with all forms of thrombotic microangiopathy. Therapeutic plasma exchange was a requirement for analysis and 65 patients were referred to our institution; 66% of patients were female and median age at presentation was 52 years. Bacterial infection was the most commonly identified etiologic factor and in the multivariate model was the only significant variable associated with survival outcome (odds ratio 5.1, 95% confidence interval, 1.2-21.7). As infection can be considered a common trigger event for thrombotic microangiopathy, patients with hepatobiliary sepsis may benefit from elective cholecystectomy. We conclude that bacterial infection frequently triggers TTP and other thrombotic microangiopathies in patients with preexisting risk factors and propose a model for the development of these syndromes.