Thrombocytopenia

Thrombocytopenia
It is a platelets count less than 150 ×109/L. It is classified according to the nature of defect into:
1. Impaired production.
2. Peripheral destruction.
3. Abnormal distribution.

Impaired platelets production
1. Hypoplasia: aplastic anemia, idiopathic megakaryocytic hypoplasia and drug induced megakaryocytic hypoplasia.
2. Bone marrow infiltration: TB, leukemia, lymphoma and secondary metastasis. They suppress megakaryocytes.
3. Metabolic defect related to megakaryocytes: B12 or folate deficiency, alcoholism and cytotoxic drugs.
4. Congenital defect of platelets: Thrombocytopenia with absent radius (TAR), Wiskott megakaryocytes defect and may-Hegglin disease (abnormal leukocytes and thrombocytopenia).
5. Viral infection: suppress megakaryocytes.

Peripheral platelets destruction
Immune:
• Auto-immune:
1. Auto-immune idiopathic thrombocytopenic purpura (ITP or AITP).
2. Secondary auto-immune thrombocytopenia.
3. Acute post viral thrombocytopenia.
4. Drug induced thrombocytopenia.

• Allo-immune:
1. Neonatal purpura.
2. post transfusion purpura.
3. purpura associated with connective tissue diseases or solid tumors or infections (bacterial, viral or parasitic).