Infection in Patients with Suspected Thrombotic Microangiopathy Based on Clinical Presentation

Background and objectives In contrast to shigatoxin-associated Escherichia coli (STEC) causing hemolytic uremic syndrome, STEC-unrelated infections associated with thrombotic microangiopathy are less characterized. Design, setting, participants, & measurements Our retrospective study in a four-hospital institution of 530 consecutive patients with adjudicated thrombotic microangiopathies during the 2009?2016 period studied STEC-unrelated infections? epidemiology and major outcomes (death, acute dialysis, and major cardiovascular events). Results STEC-unrelated infection was present in 145 of 530 (27%) patients, thrombotic microangiopathies without infection were present in 350 of 530 (66%) patients, and STEC causing hemolytic and uremic syndrome was present in 35 of 530 (7%) patients. They (versus thrombotic microangiopathy without infection) were associated with age >60 years (36% versus 18%), men (53% versus 27%), altered consciousness (32% versus 11%), mean BP <65 mm Hg (21% versus 4%), lower hemoglobin and platelet count, and AKI (72% versus 49%). They were associated with more than one pathogen in 36 of 145 (25%) patients (either isolated [14%] or combined [86%] to other causes of thrombotic microangiopathy); however, no significant clinical or biologic differences were noted between the two groups. They were more frequently due to bacteria (enterobacteria [41%], Staphylococcus aureus [11%], and Streptococcus pneumonia [3%]) than viruses (Epstein?Barr [20%], cytomegalovirus [18%], influenza [3%], hepatitis C [1%], HIV [1%], and rotavirus [1%]). STEC-unrelated infections were independent risk factors for in-hospital death (odds ratio, 2.22; 95% confidence interval, 1.18 to 4.29), major cardiovascular event (odds ratio, 3.43; 95% confidence interval, 1.82 to 6.69), and acute dialysis (odds ratio, 3.48; 95% confidence interval, 1.78 to 7.03). Bacteria (versus other pathogens), and among bacteria, enterobacteria, presence of more than one bacteria, and E. coli without shigatoxin were risk factors for acute dialysis. Conclusions Infections are frequent thrombotic microangiopathy triggers or causes, and they are mostly unrelated to STEC. Infections convey a higher risk of death and major complications. The most frequent pathogens were enterobacteria, S. aureus, Epstein?Barr virus, and cytomegalovirus. Podcast This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021_09_07_CJN17511120.mp3