Anaemia - Pathophysiological approach

Pathophysiology

• Impaired production
• Increased destruction
• Blood loss

Impaired production

• Inadequate substrate - e.g. B12, folate, iron (v intake, v absorption, ^ loss)
• Bone marrow depression - haematological malignancy e.g. leukaemia, drugs, infection, other infiltrative processes
• Endocrine mediated - v erthypoetin (renal failure), v thyroid

Increased destruction

• Abnormal haemoglobin e.g. spherocytosis, elliptocytosis, sideroblasts, sickle cell
• Abnormal spleen - causes of massive splenomegaly
• Immune mediated e.g. ABO incompatibility, Rh incompatibility, autoimmune triggers (infection, drugs)
• Mechanical intravascular destruction e.g. cardiac valve lesions

Increased loss (acute/rapid or chronic/slow)

• GIT bleeding (common)
• Vaginal bleeding
• Trauma / Post surgical - internal or external or via orifices