Thrombotic Thrombocytopenic Purpura

Excerpt

Thrombotic thrombocytopenic purpura (TTP) is a type of microangiopathic hemolytic anemia that classically has been characterized by the pentad of fever, thrombocytopenia, hemolytic anemia, renal dysfunction, and neurologic dysfunction. TTP results from either a congenital or acquired decrease/absence of the von Willebrand factor-cleaving protease ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif member 13). Low levels of ADAMTS13 result in microthrombi formation, which leads to end-organ ischemia and damage. This is due to the inability of the ADAMTS13 to inactivate the large multimer von Willebrand factor (VWF) that is necessary to prevent spontaneous coagulation. Unchecked, the large multimers have a tremendous avidity to bind platelets and initiate thrombi formation. The central nervous system (CNS) and kidneys are the two most common organ systems affected by TTP. Timely diagnosis is very important because TTP is a medical emergency which, without treatment, has a mortality of about 90%. About 80% of patients respond to initial treatment, and the post-treatment mortality is 10 to 15%.