#1231 Atypical uremic hemolytic syndrome diagnosis, therapeutic management, control and follow-up in pregnancy: about a case
Authors: Perez Mariana Josefa Arranz , Lagier María Asunción Maciá , Moya Elisa Cabello , Munro Rebecca 
Published: May 2024

Abstract

Background and Aims
Atypical hemolytic uremic syndrome (aHUS) is a clinical entity characterized by non immune hemolytic anemia, thrombopenia, and renal failure in which the lesions are mediated by a process of thrombotic microangiopathy, mutations in its genes that lead to uncontrolled activation. of C5 and formation of the membrane attack complex. Its correct diagnosis allows prescribing treatment based on eculizumab, a C5 inhibitor.
The clinical case of a patient with aHUS is presented, who three months after diagnosis, becomes pregnant. The objective is to highlight the importance of early differential diagnosis for the early establishment of effective treatment of this pathology, as well as management during pregnancy, childbirth and the postpartum period. The pathophysiology, diagnosis and genetic study are updated, as well as the therapeutic management of aHUS.

Case Reports
27 year old women with no personal or family history of interest. She went to the emergency room in the full pandemic by SARSCov2 due to choluric urine along with fever of 38, myalgias and generalized arthralgias. At that time, PCR positive SARSCov2, deterioration of renal function was noted with Creatinine of 1.8 mg/dl (previous normal), LDH 1954 u/l, Platelets 21000, Hemoglobin 14.4 g/dl without schistocytes in smear, albumin/creatinine ratios 8700 and intense hematuria. It was interpreted as thrombotic thrombocytopenic purpura receiving corticosteroids, rituximab and plasmapheresis. After 48 hours, thrombopenia persists, schistocytes appear in smears and renal function deteriorates creatinine to 2.8 mg/dl. ADAMS 13 is received at normal values, considering at this time a diagnosis of aHUS, the previous treatment is interrupted and a dose of eculizumab 900 mg is received, doses of 900 per week are scheduled for 4 weeks in the fifth week 1200 mg and from Then on biweekly dose 1200 mg of eculizumab. At the third week of treatment, renal function has already normalized, hemolysis data have disappeared, Htcro and platelets have returned to normal. Proteinuria and hematuria disappears which has been maintained up to now.
Good tolerance to treatment without any incidence, presenting a positive pregnancy test at three months.
During pregnancy treatment with eculizumab is maintained. We continued with the biweekly regimen with 1200 mg of eculizumab until delivery. Labor is induced at week 37 receiving a extra dose of 1200 mg in the first 24 hours of delivery and continuing with 4 doses of 1200 mg once a week. Afterwards the dose is changed to a biweekly dose without modifying it throughout lactation until it ends. The reason is to avoid complement deregulation in the context of pregnancy and therefore ensure blockade. Subsequently it is done Switch to ravulizumab when breastfeeding begins as follows: A loading dose of 2700 mg (according to the interval of patient's weight) 15 days after the last dose of eculizumab. The maintenance dose is 3300 mg every 8 weeks starting 2 weeks after the loading dose. Normal kidney function has been maintained.
She presented on debut positive serology for parvovirus B19, receiving treatment with Immunoglobulins and PCR SARSCov2 was positive prescribing treatment with remdesivir.
Vitus (CMV, HBV, HCV and HIV) serology was negative and autoimmune study as well as study of complement and proteinogram were negative or within normal limits. No data suggestive of a neoplastic process. Genetic study has been detected a pathogenic variant associated with aHUS.

Conclusion
We found a heterozygous carrier patient in genetic study, who developed aHUS during a Sars-cov2 infection, which could have been a trigger for its clinical expression. The clinical course of this case highlights how crucial it is to identify atypical hemolytic uremic syndrome. The early initiation of eculizumab improves the prognosis and quality of life, with pregnancy becoming increasingly more likely and therapy with eculizumab does not have safety problems in this regard, although pregnant patients with aHUS should be closely monitored close during pregnancy and postpartum.