The thrombocytopenic purpuras. Recognition and management.

Idiopathic thrombocytopenic purpura (ITP) and thrombotic thrombocytopenic purpura (TTP), are distinct entities. ITP is a relatively common autoimmune disorder typically manifesting with isolated thrombocytopenia. The acute form, more common in children, is a self-limiting, often post-viral disease. Therapy, if indicated, usually consists of a brief course of steroids or intravenous IgG. Chronic ITP, more common in adults, rarely remits spontaneously. Most patients respond initially to steroids, but generally the disease relapses when steroids are tapered. Splenectomy offers a 70% chance of cure. A variety of treatment options exist for patients not responding to splenectomy. The treating physician must choose the most effective and least toxic treatment for the individual patient. TTP is a rare, often life-threatening, multisystem disease of unknown aetiology. Its hallmark is widespread occlusion of the microcirculation by platelet aggregates. The clinical symptoms usually respond dramatically to plasma exchange therapy. Steroids, antiplatelet agents and vincristine may also be useful. Splenectomy should be considered in patients with multiple relapses. More specific therapy awaits a fuller understanding of the pathogenesis of this disease.