APPROACHING PREGNANCY-ASSOCIATED THROMBOTIC MICROANGIOPATHIES IN THE FACE OF DIAGNOSTIC UNCERTAINTY

Abstract

SESSION TITLE: Medical Student/Resident Critical Care Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Critical illness is infrequently encountered in pregnant patients though remains a prominent concern due to potential maternal and fetal morbidity and mortality. We report a case of a female in her second trimester with severe microangiopathic hemolytic anemia, thrombocytopenia, and end organ damage to highlight the emergent measures and multidisciplinary action necessary to avoid adverse outcomes when the ultimate diagnosis is not immediately clear. CASE PRESENTATION: A 26-year-old female, gravida 4, para 1, with a medical history of chronic kidney disease due to focal segmental glomerulosclerosis presented at 21 weeks and 2 days gestation with abdominal pain, nausea, and headaches. On initial evaluation the patient was found to have hypertensive emergency, acute kidney injury (AKI), acute liver injury, and intrauterine fetal demise. Within 48 hours of presentation the patient required transfusions for worsening thrombocytopenia and acute anemia with a markedly elevated lactate dehydrogenase (LDH), undetectable haptoglobin and 5% schistocytes. The patient underwent an urgent dilation and evacuation and plasma exchange (PE) for a suspected thrombotic microangiopathy (TMA). She was found to have normal level of ADAMTS13 ruling out thrombotic thrombocytopenic purpura (TTP) and PE was stopped. Cell counts and liver function gradually improved; however, the patient had progression of her AKI with a creatinine peak of 10.9mg/dL one week after initial presentation. Autoimmune and complement studies were obtained revealing a significant elevation in the alternative pathway BB complement level concerning for atypical hemolytic uremic syndrome (aHUS). A renal biopsy was obtained to confirm the presence of TMA. The patient had gradual improvement in renal function and was ultimately discharged with specialty follow up to review the biopsy and make definitive decisions on therapeutic management. Unfortunately the renal biopsy was non-diagnostic due to inadequate tissue sampling and the patient failed to return for outpatient appointments. DISCUSSION: Thrombotic microangiopathies are a rare and devastating group of disorders carrying high morbidity and mortality and pose a diagnostic challenge due to the overlapping clinical and laboratory findings. Pregnancy-specific conditions such as HELLP (hemolysis, elevated liver enzymes and low platelets) syndrome must be differentiated from other causes of TMA including TTP and aHUS. Certain clinical features such as the degree of laboratory derangements and timing during pregnancy may suggest an etiology; however, definite diagnosis often takes several days. CONCLUSIONS: This case demonstrates the necessity for rapid intervention, such as PE for TTP and aHUS, as well as emergent delivery for HELLP Syndrome, even amidst relative diagnostic uncertainty as delay in therapy contributes to worse outcomes. Reference #1: Fakhouri F, Vercel C, Fremeaux-Bacchi V. Obstetric nephrology: AKI and thrombotic microangiopathies in pregnancy. Clin J Am Soc Nephrol. (2012) 7:2100–6. 10.2215/CJN.13121211. 10.2215/CJN.13121211 Reference #2: Gupta M, Feinberg B, Burwick R. Thrombotic microangiopathies of pregnancy: differential diagnosis. Pregnancy Hypertens. (2018) 12:29–34. 10.1016/j.preghy.2018.02.007 Reference #3: Pishko A, Levine L, Cines C, . Thrombocytopenia in pregnancy: diagnosis and approach to management. Blood Rev (2020) 40. 0.1016/j.blre.2019.100638 DISCLOSURES: No relevant relationships by Kelsey Black, source=Web Response No relevant relationships by Megan Conroy, source=Web Response No relevant relationships by Adam Shaver, source=Web Response