Classification of Thrombocytopenia :

Thrombocytopenia in neonates, as in adult can be caused by decreased production, increased platelet destruction and platelet pooling in enlarged spleen or by combination of these mechanisms. Characterization of mechanism responsible for the thrombocytopenia has practical implication in the management of these patients. For example, transfusion of platelets into an infant with consumptive coagulopathy or peripheral destruction may be of limited or no benefit, since the platelets transfused will be destroyed in a very short time. Most infants in whom thrombocytopenia develops are ill, are premature or associated with other disorders that will contribute to thrombocytopenia including bacteremia, sepsis, DIC, etc. Usually the thrombocytopenia is caused by maternal factors such as anti-platelet-allo or autoantibodies that have crossed the placenta. However, commonest cause of low platelet count is improper collection of blood or inadequate anticoagulants and hence it is wise to confirm the laboratory reports of low platelet count with peripheral blood smear examination which will show clumps of platelet when platelet count and functions are normal.

On the basis of pathophysiological factors, neonatal thrombocytopenia can be classified as: -

• Immune-mediated
  
  
• Associated with infection - Bacterial or Non-bacterial
  
  
• Drug-Related
  
  
• Increased peripheral consumption of platelets - Disseminated Intravascular Coagulation, Narcotizing enterocolitis, hypersplenism
  
  
• Genetic and Congenital Anomalies
  
  
• Miscellaneous.

Immune-mediated Thrombocytopenia

Immune mediated neonatal thrombocytopenia could be due to:

• Neonatal allo-immune thrombocytopenia (NAIT)
  
  
• Incidental thrombocytopenia of pregnancy or Gestational thrombocytopenia
  
  
• Autoimmune thrombocytopenic purpura