Obstetric atypical hemolytic uremic syndrome and sepsis: is there a relationship?

Background. Atypical hemolytic uremic syndrome (aHUS) and sepsis represent the most severe forms of obstetric thrombotic microangiopathy (TMA). At the same time, the differential diagnosis between sepsis and aHUS in obstetric practice is extremely difficult, especially considering the possibility of their combination. Objective: to assess the peculiarities of the course and prognosis of aHUS in combination with sepsis in the postpartum period. Patients/Methods. The uncontrolled non-rando-mized retrospective study included 98 patients with obstetric aHUS: group 1 — 78 patients with “pure” obstetric aHUS (“aHUS” group), group 2 — 20 patients with a combination of aHUS and sepsis (“aHUS + sepsis” group). The laboratory parameters accepted in general clinical practice (general, biochemical, immunological blood tests, coagulogram, D-dimer level) were determined. Results. Complement-activating conditions were identified in all patients, among which the frequency of urinary and obstetric infections was significantly higher in group 2 (p < 0.05). Patients of “aHUS + sepsis” group, in addition to TMA signs, had pronounced neutrophilic leukocytosis (25.0 [19.5; 28.0]×109/L), increased levels of procalcitonin (10.0 [5.4; 10.5] ng/ml), presepsin (1992.0 [167.0; 3000.0] pg/ml), C-reactive protein (61.0 [23.0; 111.0] mg/L) and more expressed than in patients of “aHUS” group, coagulopathy: low fibrinogen level (1.1 [1.0; 1.9] g/L vs. 3.5 [2.7; 4.2] g/L; p = 0.005) with increased D-dimer level (over 0.5 µg/ml). In addition to antibacterial and plasma therapy, 49 out of 78 (62.8%) patients in “aHUS” group and 11 out of 20 (55.0%) in “aHUS + sepsis” group received eculizumab at a dose of 900 mg once a week for 4 weeks, on the 5th week — 1200 mg once a week, followed by a transition to a maintenance regimen (1200 mg every 2 weeks). Survival in “aHUS + sepsis” group was almost twice as low (55.0% vs. 84.7%) as in “aHUS” group. Conclusions. The prognosis of obstetric aHUS in combination with sepsis is extremely unfavorable, necessitating timely detection and treatment of infectious complications in pregnant women and puerperas. Taking into account the role of complement activation in the pathogenesis of sepsis, the appointment of eculizumab after the infection has been controlled can be discussed. © 2022, Hemostasis and Rheology LLC. All rights reserved.