PIP: Thrombotic thrombocytopenic purpura (TTP) is a syndrome that occurs mainly 
in adults with multiorgan microvascular thrombosis consisting of 
thrombocytopenia, microangiopathic hemolytic anemia, neurologic symptoms, renal 
involvement, and fever. The female to male ratio is 3:2, and peak incidence 
occurs in the 3rd decade of life. Clinical signs are the consequence of hyaline 
thrombosis and occlusion of capillaries and arterioles. Renal ailment manifests 
itself in hematuria and proteinuria with azotemia and even overt renal failure. 
In severe disease, azotemia is typical of hemolytic uremic syndrome (HUS). TTP 
was first described in 1925 by Moschcowitz. The clinical picture of TTP consists 
of a prodromal phase, a viruslike disease occurring in up to 40% of patients. 
60% have neurologic disturbances, 90% have purpura initially, and fever occurs 
in all. Anemia is often severe with hemoglobin values of 7-9 gm/dl, renal 
involvement in 90%, and renal failure in 40-80% of patients. Clinical variants 
include the acute and fulminant variety mortality, the chronic form, and the 
relapsing form. Predisposing factors and triggering agents are autosomal 
recessive inherited traits in acute idiopathic TTP, systemic diseases, tumor 
antigens, pregnancy and puerperium, viruses (endotoxins for HUS), and possibly 
oral contraceptives and hypertension. Therapy includes corticosteroids 
(prednisone 100-400 mg/day); heparin for postpartum HUS; and antiplatelet agents 
(Dextran 70, aspirin, and dipyridamole in high doses). The infusion of PGI2 is 
controversial; splenectomy is also questionable; and vincristine, azathioprine, 
and cyclophosphamide have unproven efficacy. Fresh-frozen plasma exchange is the 
method of choice as it produces survival in 90%. Others are iv immunoglobulins, 
vitamin E, and dialysis and renal transplant. Platelet transfusions are 
contraindicated because of sudden death and decreased survival.