Thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a blood disorder that results in blood clots forming in small blood vessels throughout the body. This results in a low platelet count, low red blood cells due to their breakdown, and often kidneys, heart, and brain dysfunction. Symptoms may include large bruises, fever, weakness, shortness of breath, confusion, and headache. Repeated episodes may occur. Thrombotic thrombocytopenic purpura (TTP) is a blood disorder that results in blood clots forming in small blood vessels throughout the body. This results in a low platelet count, low red blood cells due to their breakdown, and often kidneys, heart, and brain dysfunction. Symptoms may include large bruises, fever, weakness, shortness of breath, confusion, and headache. Repeated episodes may occur. In about half of cases a trigger is identified, while in the remainder the cause remains unknown. Known triggers include bacterial infections, certain medications, autoimmune diseases such as lupus, and pregnancy. The underlying mechanism typically involves antibodies inhibiting the enzyme ADAMTS13. This results in decreased break down of large multimers of von Willebrand factor (vWF) into smaller units. Less commonly TTP is inherited from a person's parents, known as Upshaw–Schulman syndrome, such that ADAMTS13 dysfunction is present from birth. Diagnosis is typically based on symptoms and blood tests. It may be supported by measuring activity of or antibodies against ADAMTS13. With plasma exchange the risk of death has decreased from more than 90% to less than 20%. Immunosuppressants, such as glucocorticoids, and rituximab may also be used. Platelet transfusions are generally not recommended. About 1 per 100,000 people are affected. Onset is typically in adulthood and women are more often affected. About 10% of cases begin in childhood. The condition was first described by Eli Moschcowitz in 1924. The underlying mechanism was determined in the 1980s and 1990s. The signs and symptoms of TTP may at first be subtle and nonspecific. Many people experience an influenza-like or diarrheal illness before developing TTP. Neurological symptoms are very common and vary greatly in severity. Frequently reported symptoms include feeling very tired, confusion, and headaches. Seizures and symptoms similar to those of a stroke can also be seen. Other symptoms include, but are not limited to jaundice or paleness of the skin, a fast heart rate or shortness of breath, or pinpoint-sized purple or reddish dots on the skin known as petechiae. As TTP progresses, blood clots form within small blood vessels (microvasculature), and platelets (clotting cells) are consumed. As a result, bruising, and rarely bleeding can occur. The bruising often takes the form of purpura, while the most common site of bleeding, if it occurs, is from the nose or gums. Larger bruises (ecchymoses) may also develop. The classic presentation of TTP, which occurs in less than 10% of people, includes five medical signs. These are: High blood pressure (hypertension) may be found on examination. TTP, as with other microangiopathic hemolytic anemias (MAHAs), is caused by spontaneous aggregation of platelets and activation of coagulation in the small blood vessels. Platelets are consumed in the aggregation process and bind vWF. These platelet-vWF complexes form small blood clots which circulate in the blood vessels and cause shearing of red blood cells, resulting in their rupture and formation of schistocytes.