An unusual platelet function defect: report of 19 cases.

Selective impairment in platelet responsiveness to epinephrine has been seen in certain acquired conditions and very rarely as a hereditary disorder. To the best of our knowledge this hereditary defect has been described in a single family and in two other individuals. We describe here 19 cases of this defect. Subjects with history of generalized bleeding with a prolonged bleeding time, PF3 availability or prothrombin consumption index and a normal platelet count, prothrombin time, activated partial thromboplastin time, clot solubility were subjected to platelet aggregation. Those of these who showed a normal aggregation with ADP, collagen, arachidonic acid and an absent aggregation with epinephrine were included in our study group. Subjects with history or findings suggestive of antiplatelet drug intake or any acquired condition giving rise to this abnormality were excluded from this study. 74% of the patients had onset of bleeding manifestations since childhood (<14 years) with a mean age at onset of 10.4 years. All patients presented with mild bleeding manifestations, the commonest symptom being appearance of recurrent ecchymotic spots. In females, menorrhagia was the commonest symptom. We present here probably the first report of the occurrence of hereditary platelet aggregation defect selectively with epinephrine in Indian patients.