Microangiopatías trombóticas: púrpura trombocitopénica trombótica y síndrome hemolítico urémico. Una revisión más allá del espectro clínico de la enfermedad

Thrombotic microangiopathy (TMA) is related to a histological lesion in arterioles and capillaries, characterized by thickening and inflammation of the vascular wall, detachment of endothelial cells, enlargement of the subendothelial space with accumulation of proteins and cell lysis material, and the presence of platelet thrombi that occlude the vascular lumen. There are two clinical entities with primary thrombotic microangiopathy lesions: thrombotic thrombocytopenic purpura and hemolytic uremic syndrome. Thrombotic thrombocytopenic purpura is related to a deficit or dysfunction of disintegrin and metalloproteinase activity, which splits the bond of von Willebrand factor, a protein involved in the clotting process. Clinically it is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and increased serum lactate dehydrogenase. On contrast, the hemolytic uremic syndrome is defined by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury, and can be classified as typical and atypical. The typical hemolytic uremic syndrome is associated with the prodrome of diarrhea after infection with Shiga toxin-producing Escherichia coli, while atypical HUS is associated with abnormalities in the alternative complement pathway, Streptococcus pneumoniae infections, systemic lupus erythematosus, disorders of the cobalamin C metabolism, among others.