Chapter 18 - Thrombotic thrombocytopenic purpura and other microangiopathies

Summary

Thrombotic microangiopathies (TMAs) describe the clinical and pathohistological effects of thrombosis in small vessels. The diagnostic challenge is the differentiation from acute fatty liver of pregnancy (AFLP), preeclampsia (PET) or eclampsia, HELLP (hemolysis, elevated liver enzymes, low platelets), antiphospholipid syndrome (APS), systemic lupus erythematosus (SLE), hemolytic uremic syndrome (HUS), and disseminated intravascular coagulation (DIC). Immune thrombocytopenic purpura (ITP) occurs in 5% of pregnancies with thrombocytopenia and is a result of immunological peripheral platelet destruction. Women presenting with thrombotic thrombocytopenic purpura (TTP) during pregnancy appear to fall into two groups: those with congenital TTP and those with acquired, antibody mediated TTP. Intrahepatic cholestasis of pregnancy (ICP) has been associated with impaired sulphation and abnormalities of progesterone metabolism. SLE is an autoimmune disease, the active phase of which may be associated with thrombocytopenia, hemolytic anemia, pancytopenia, and an increase in double-stranded DNA.