Size of spleen rather than amount of platelet sequestration may determine long term responses to splenectomy in adult idiopathic thrombocytopenic purpura.

Fourteen adults with idiopathic thrombocytopenic purpura suffered a relapse after treatment with steroids, vinca alkaloids, or intravenous gammaglobulin. Splenic sequestration of platelets labelled with 111In-oxine was assessed, and the patients then underwent splenectomy. During follow up of four to 47 months (mean 20.7) none of the patients required further treatment, including three of 14 who showed partial relapses. Splenic sequestration patterns did not predict relapses, but an unexpected finding was that patients who relapsed had significantly smaller spleens. It is concluded that splenectomy is beneficial in most adult patients with idiopathic thrombocytopenic purpura and that radiological techniques to measure the size of the spleen may be useful in predicting which patients may relapse.