Causes of Blood Cell Destruction (Hemolysis, Thrombocytopenia, Neutropenia)

Blood cell destruction occurs via multiple mechanisms:

Red Cells (Hemolytic Anemia)

• Immune – warm/cold AIHA, drug-induced, transfusion reaction.
• Microangiopathic – TTP, HUS, DIC, malignant hypertension, mechanical valves.
• Intrinsic defects – sickle cell, thalassemia, G6PD deficiency, hereditary spherocytosis.
• Infections – malaria, babesiosis, Bartonella, Clostridium.

Platelets (Thrombocytopenia)

• Immune (ITP) – anti-GPIIb/IIIa antibodies.
• Consumption – DIC, TTP, HUS, massive transfusion.
• Sequestration – splenomegaly.
• Drug-induced – heparin (HIT), quinine, vancomycin.

White Cells (Neutropenia)

• Autoimmune – anti-neutrophil antibodies.
• Drug-induced – chemo, clozapine, antithyroid, sulfonamides.
• Infection – viral (HIV, EBV), bacterial (typhoid), sepsis consumption.
• Marrow failure – aplastic anemia, MDS, leukemia, B12/folate deficiency.

Diagnosis requires CBC with differential, smear review, reticulocyte count, Coombs, specific assays.