Chronic relapsing thrombocytopenia with thrombasthenia

Abstract

Idiopathic thrombocytopenic purpura (ITP) results from increased platelet destruction due to an extra-corpuscular factor. Qualitative platelet abnormalities with defective haemostatic function have long been recognized, but intracorpuscular defects causing premature platelet destruction have only recently been described. The latter have usually been familial, and not associated with an abnormal extracorpuscular thrombocytolytic agent. The case was described of a 14-yr. old boy, with a non-familial thrombocytopenic purpura, whose clinical features and platelet survival times were compatible with a diagnosis of ITP. In addition a functional abnormality of his platelets had been demonstrated. The patient's platelet count fluctuated between 1,000/mm. 3 and 150,000/mm. 3 over a 12 yr. period. The following studies were done when the platelet count was 120,000/mm. 3 An increased number of megakaryocytes of normal morphology were present in bone marrow preparations. Autologous and isologous platelet survival times were similarly shortened. Blood films showed large platelets, but no other morphological abnormalities were present on light or electron microscopy. Bleeding times, clot retraction, platelet fibrinogen uptake and coagulation indexes were all normal. Platelet aggregation was studied at 37°. Aggregation occurred with adrenalin and thrombin, the latter being blocked with adenosine. No aggregation occurred with Ristocetin or 5 hydroxy-tryptamine though minimal aggregation occurred with collagen, and ADP at room temperature. Latex particles were phagocytozed normally, but this process was not associated with platelet aggregation on electron micrographs. Platelet factor III was reduced, and platelet factor IV, though present, was not released by ADP. The abnormalities of morphology and membrane-associated functions suggested a defect in the platelet membrane, in the presence of an extracorpuscular thrombocytolytic factor.