Acute kidney injury in pregnancy: the thrombotic microangiopathies

Acute kidney injury (AKI) is a rare but serious complication of pregnancy. Although prerenal and ischemic causes of AKI are most common, renal insufficiency can complicate several other pregnancy-specific conditions. In particular, severe preeclampsia/HELLP syndrome, acute fatty liver of pregnancy (AFLP) and thrombotic thrombocytopenic purpura (TTP) are all frequently complicated by AKI, and share several clinical features which pose diagnostic challenges to the clinician. In this article, we discuss the clinical and laboratory features, pathophysiology and treatment of these 3 conditions, with particular attention to renal manifestations. It is imperative to distinguish these conditions to make appropriate therapeutic decisions which can be lifesaving for the mother and fetus. Typically AFLP and HELLP improve after delivery of the fetus, whereas plasma exchange is the first-line treatment for TTP.