Thrombotic microangiopathy

Overview
Thrombotic microangiopathies are a category of pathologies that result in thrombosis in capillaries and arterioles. This process leads to thrombocytopenia and a variety of other symptoms such as: anemia, purpura, renal failure (some), schistocytes (fragmented blood cells severed by fibrin products) and ischemic injury to cells.

Categories
Bacterial toxins are the primary cause of one category of thrombotic microangiopathy known as HUS or hemolytic uremic syndrome. The other major category is TTP or thrombotic thrombocytopenic purpura caused by autoimmune or hereditary dysfunctions that activate the coagulation cascade or the complement system.

Some sources group TTP and HUS together, while other sources express skepticism about their common pathophysiology.

Presentation
The clinical presentation typically includes: fever, microangiopathic hemolytic anemia (see schistocytes in a blood smear), renal failure, thrombocytopenia, neurological manifestations.