AUTHOR=Leiva Marina , Navarro Gustavo , Carpio J Daniel , Ardiles Leopoldo TITLE=Case report: Thrombotic thrombocytopenic purpura in a pregnant woman with lupus membranous nephropathy: a diagnostic challenge JOURNAL=Frontiers in Nephrology VOLUME=Volume 4 - 2024 YEAR=2024 URL=https://www.frontiersin.org/journals/nephrology/articles/10.3389/fneph.2024.1343594 DOI=10.3389/fneph.2024.1343594 ISSN=2813-0626 ABSTRACT=A 27-year-old female at 20th week of pregnancy was admited with edema, foamy urine, but normal blood pressure. Her blood count was normal, she had proteinuria of 3 g/day, crea�nine 0.4 mg/dl, albumin 2.4 g/dl, and cholesterol 355 mg/dl. An�nuclear an�bodies 1/160, but An�-DNA, an�cardiolipin an�bodies and lupus an�coagulant were nega�ve, with normal serum C3 and C4. A renal biopsy showed secondary membranous glomerulopathy, most likely lupus class V pure.Steroids, azathioprine, and aspirin were ini�ated, up to 28 weeks of pregnancy, when she developed severe hypertension, photopsia, headache, anasarca, extensive bruising of the extremi�es, severe anemia, thrombocytopenia, and crea�nine rose to 2.09 mg/dl with preserved diuresis. A female infant, 1045 grams, was delivered by emergency caesarean sec�on. Following the surgery, she experienced diplopia, dysarthria, bradypsychia, and sensory altera�ons in the lower extremi�es, necessita�ng emergency hemodialysis due to pulmonary conges�on. Blood smear revealed schistocytes, LDH elevated at 1148 IU/L, while transaminases and liver func�on remained normal, sugges�ng thrombo�c thrombocytopenic purpura. ADAMTS13 revealed 6% ac�vity with the presence of inhibitor. Mycophenolate and daily plasmapheresis with fresh frozen plasma replacement yielded unsa�sfactory response, unaffected by the addi�on of methylprednisolone pulses and rituximab. Eventually, intravenous cyclophosphamide was introduced, resul�ng in complete hematological remission and normaliza�on of ADAMTS13, however dialysis-dependence persisted and four years later, right renal cancer prompted bilateral nephrectomy. A�er a total follow-up of six years, she remained free of neoplas�c recurrence and lupus ac�vity, receiving prednisone and hydroxychloroquine. The differen�al diagnosis of microangiopathic syndrome in a pregnant lupus pa�ent is discussed.