#2262 Renal outcomes of postpartum atypical hemolytic uremic syndrome treated with plasma exchange

Abstract

Abstract Background and Aims Postpartum acute kidney injury (AKI) with features of thrombotic microangiopathy (TMA) are particularly challenging and complex cases. Causes include Preeclampsia (PE), hemolysis, elevated liver enzymes and low platelet count syndrome (HELLP) and atypical hemolytic uremic syndrome (aHUS). In a limited resource setting, it is difficult to diagnose such cases with more than standard blood tests. Therapeutic Plasma exchange (TPE) is the only available option for treatment in the absence of complement inhibitors. This study evaluates renal outcomes in patients with aHUS treated with plasma exchange. Method This is a single centre observational study conducted in a Tertiary Obstetric Intensive Care unit. The data of women who were admitted with postpartum AKI from January 2021 to October 2023 was retrospectively collected and analyzed. We used the following criteria to diagnose postpartum atypical HUS (Serum creatinine ≥1.9 mg/dL, Lactate dehydrogenase (LDH) ≥1832 U/L, or serum creatinine ≥1.9 mg/dL in combination with LDH ≥600 U/L) [1]. Inclusion criteria include women older than 18 yrs with microangiopathic hemolytic anaemia, schistocytes on peripheral blood film, negative direct antiglobulin test (DAT) and platelet count <100 /mm3.Lack of improvement of kidney functions and hemolysis 72 hours after delivery. Patients with sepsis, disseminated intravascular coagulopathy (DIC), postpartum hemorrhage (PPH) and chronic kidney disease were excluded. We identified 10 patients with postpartum aHUS. Peak creatinine, LDH, AST and Nadir platelet count and hemoglobin were recorded. Patients were followed up in the nephrology outpatient clinic. Results Fifty-two patients developed postpartum AKI in the study period. Ten patients (19%) were diagnosed with aHUS according to the above-mentioned criteria. Mean age was 24.5 ± 6.9 yrs. Median peak creatinine 5.1 (2.6-7) mg/dl, LDH 1950 (612-4000) U/L, AST 246 (150-699) U/L. Median nadir hemoglobin 7.25 (6-8.2) g/dl and platelets 57 (41-95)/mm3. All 10 patients received 3 to 6 sessions of TPE guided by platelets and LDH levels. All patients required at least 3 sessions of hemodialysis. Eight patients received TPE with plasma filter and 2 had centrifugal TPE (due to lack of plasma filters). Two patients died during ICU admission. Two months after discharge 4 (50%) patients had partial recovery of kidney functions average creatinine (3.5 ± 0.8) mg/dl and four (50%) remained dialysis dependent. Six of these patients had kidney biopsies, three biopsies showed a picture of thrombotic microangiopathy and two showed thrombotic microangiopathy with renal cortical necrosis. The other patient was lost to follow up. Conclusion It is difficult to diagnose and treat aHUS in a resource limited setting. The available treatment with therapeutic plasma exchange has poor renal outcomes.