Q. Why is there a microangiopathic hemolytic anemia in thrombotic thrombocytopenic purpura and disseminated intravascular coagulation?

A. In both thrombotic thrombocytopenic purpura (TTP) and disseminated intravascular coagulation (DIC), there are little thrombi forming all over the place. The composition of the thrombi in TTP is different than it is in DIC – but that doesn’t change the fact that you get busted up red cells in each disorder.

Normally, when red cells are squeezing through capillaries, it’s a pretty tight fit. They barely fit as it is. So if you add a thrombus in there (even a little one), the red cells passing by will likely get snagged. When the resulting red cell fragments regain their composure on the other side of the thrombus, they no longer have nice round biconcave shapes – they are now small, pointy schistocytes. Some of them are perfect little triangles, like the triangulocyte (no, really, that’s what it’s called) above.

Microangiopathic hemolytic anemia is a great name for this anemia: micro=small, angio=vessels, path=bad stuff.