The Clinical Presentation of Thrombotic Microangiopathy

Thrombotic microangiopathy (TMA) is characterized by thrombocytopenia, microangiopathic haemolytic anaemia and end organ damage. Microangiopathic haemolytic anaemia is caused by red blood cell fragmentation in the microvasculature, with schistocytes seen on peripheral blood film. Lactate dehydrogenase (LDH) is raised due to tissue ischemia and cell lysis. Low plasma haptoglobin is a marker of haemolysis as it binds to free haemoglobin and the complex is cleared by macrophages. Coombs test is gener negative. Renal involvement is common to most TMAs due to its vulnerability to occlusion and endothelial damage.