Evaluation of Thrombocytopenia in Megaloblastic Anemia by Platelet Indices and Megakaryocytes- Comparison with Hypoproduction and Hyperdestruction

摘要

Introduction: Thrombocytopenia may result from many mechanisms such as: marrow hypoplasia (decreased megakaryocytes), ineffective thrombopoiesis (normal to increased megakaryocytes) and increased destruction of platelets (increased megakaryocytes). The cause of thrombocytopenia in megaloblastic anemia has been postulated as hypoproduction in some studies, whereas ineffective thrombopoeisis has been proposed as the mechanism in others.Aim: This study was taken up to study the platelet indices in thrombocytopenia secondary to megaloblastic anemia, hypoproduction and hyperdesrtuction. And also aimed to evaluate the discriminative function of platelet indices in megaloblastic anemia in comparison with hypoproductive and hyperdestructive causes of thrombocytopenia and to correlate platelet indices with bone marrow megakaryocyte cellularity.Materials and Methods: Platelet indices in 32 cases of thrombocytopenias of megaloblastic etiology were compared with platelet indices of 31 cases of marrow proven hypoproductive thrombocytopnias (aplastic anemia, hypoplastic anemia, acute leukemia) and 32 cases of hyperdestructive thrombocytopnias (Immune thrombocytopenia). Descriptive analysis was used and comparison among means of platelet indices in all the groups was done with one way ANOVA using Scheffe’s test. Categorical data was analyzed using Chi-square test. Platelet indices and bone marrow megakaryocytes were analyzed and correlated in each group. A p-value of less than 0.05 was considered statistically significant.Results: The mean values platelet indices were significantly higher (p0.05). The mean P-LCR (37.4%) in megaloblastic group was intermediate between both the other groups with a significant statistical difference (p-value<0.05).Conclusion: Both hypoproduction and ineffective thrombo-poiesis are the underlying pathomechanisms in megaloblastic thrombocytopenia as evidenced by the marrow findings and platelet indices. Platelet indices are of significant discriminative value in differentiating the various causes of thrombocytopenias. We hereby infer that megaloblastic thrombocytopenia is to be included as a separate category apart from hypoproliferative and hyperdestructive groups.