Peripartum thrombotic microangiopathy —a enigma

The report by Horinoet al.1 nicely demonstrates a case of renal and systemic thrombotic microangiopathy in a pregnant lady with a background history of systemic sclerosis. The authors also lucidly explain the differentiating features between scleroderma renal crisis (SRC) and thrombotic thrombocytopenic purpura (TTP). However, apart from SRC and TTP, two other differentials should also be considered in a peripartum lady with Thrombotic microangiopathy (TMA), i.e. severe preeclampsia with HELLP and atypical hemolytic uremic syndrome (aHUS). Severe preeclampsis can be differentiated from other hypertensive disorders in pregnancy by sFLT1/PIGF ratio. Recently, FDA has approved ratio of antiangiogenic soluble fms-like tyrosine kinase 1 (sFlt-1) to pro-angiogenic factor, placental growth factor (PlGF).2 That has a high negative predictive value in ruling out severe preeclampsia. The authors also mention a elevated serum renin level in the index patient that goes against Pre-Eclampsia (PE). A high renin level is seen in SRC due to renocortical ischemia, whereas it is low/normal in PE. A subtle clinical clue in favor of severe PE in the index patient is the improvement of renal function after the delivery of the placenta. The other TMA differential in the peripartum period is aHUS caused by the abnormalities of the complement regulatory proteins. However, aHUS usually presents in postpartum period and patients have more severe degree of hemolysis, severe thrombocytopenia and occasio...
Source: QJM - Category: Internal Medicine Source Type: research