The disease Thrombotic Thrombocytopenic Purpura (TTP) is a blood disorder that affects the normal clotting process. If diagnosed correctly and treated properly this disease is acute for most patients, however due to the incidence of thrombi, if it is misdiagnosed or goes untreated, it can lead to death very quickly.
TTP can be familial or acquired. In the familial form of TTP, it has been discovered there is a congenital deficiency of the ADAMTS13 gene; this is rare. The acquired form of TTP is thought to be caused by an inhibitory autoantibody to the action of the ADAMTS13 gene which is responsible for cleaving large multimers in the clotting process. These multimers aggregate platelets or cause them to stick together and produce thrombi (George, 2007). These thrombi can lead to hemolysis or accelerated break down of red blood cells and present in the typical objective TTP symptom of purpura or small bruises under the skin (Nanda, 2007). The most urgent concern is the possibility of thrombi causing blockage in small capillaries, which could lead to myocardial infarction, renal failure, or stroke. Acquired TTP can be trigger by associated disorders such as pregnancy, surgery, and pancreatitis. It is often misdiagnosed as gastroenteritis, sepsis, transient cerebral ischemic attack, and preeclampsia.
Tests and Procedures used to Diagnose
In diagnosing TTP a Complete Blood Count (CBC) blood test should be taken which will show, according to McBrien, in the AJN, a platelet count of 2,000-10,000 per ml (1997, p.28). This is dangerously low compared to the normal of 150,000-400,000 per ml (Daniels, 2002, p. 233). The CBC will also show a hematocrit or percent of red blood cells in whole blood volume at 30% (McBrien, 1997) versus the normal of 35.9%-44.6% (Daniels, 2002). A stained red blood cell examination or peripheral blood smear will show schistocytes or fragmented red blood cell from the hemolysis.
J. N. George states that “plasma exchange is the essential component of treatment” for TTP (2007, p. 87). Plasma exchange or plasmaphoresis is done by removing blood from the patient, separating out the bad plasma, replacing it with fresh frozen plasma, and then transfusing the blood back into the patient.
Daniels, R. (2002) Delmar’s guide to laboratory and diagnostic tests. Canada: Delmar.
George, J. (2007, March-April). Evaluation and management of patients with thrombotic thrombocytopenic purpura. Journal of Intensive Care Medicine, 22(2), 82-91.
McBrien, N. J. (1997). Thrombotic thrombocytopenic purpura. American Journal of Nursing. 97(2), 28. Retrieved September 8, 2007 from OVID database.
Nanda, R. (2007, August 31). Thrombotic thrombocytopenic purpura. Retrieved September 8, 2007, from http://www.nlm.nih.gov/medlineplus/ency/article/000552.htm.