Acute kidney injury in the pregnant patient.

Acute kidney injury (AKI) is costly and is associated with increased mortality and morbidity. An understanding of the renal physiologic changes that occur during pregnancy is essential for proper evaluation, diagnosis, and management of AKI. As in the general population, AKI can occur from prerenal, intrinsic, and post-renal causes. Major causes of pre-renal azotemia include hyperemesis gravidarum and uterine hemorrhage in the setting of placental abruption. Intrinsic etiologies include infections from acute pyelonephritis and septic abortion, bilateral cortical necrosis, and acute tubular necrosis. Particular attention should be paid to specific conditions that lead to AKI during the second and third trimesters, such as preeclampsia, HELLP syndrome, acute fatty liver of pregnancy, and TTP-HUS. For each of these disorders, delivery of the fetus is the recommended therapeutic option, with additional therapies indicated for each specific disease entity. An understanding of the various etiologies of AKI in the pregnant patient is key to the appropriate clinical management, prevention of adverse maternal outcomes, and safe delivery of the fetus. In pregnant women with pre-existing kidney disease, the degree of renal dysfunction is the major determining factor of pregnancy outcomes, which may further be complicated by a prior history of hypertension.