Overview of Anaemia
May 1st, 2022
On this page:Microcytic Hypochromic AnaemiaNormocytic Normochromic AnaemiaMacrocytic Hyperchromic Anaemia
Overview
Anaemia is a very common condition that may occur in the context of reduced red blood cell production, increased red blood cell destruction, or red blood cell loss.
Look For
- Reduced serum haemoglobin (Hb) concentration
- Reduced haematocrit (HCT) / packed cell volume (PCV)
- Reduced red cell count (RCC)
Causes of Anaemia
Reduced RBC Production
- Haematinic deficiency - B12, folate, iron
- Bone marrow pathology - pure red cell aplasia, myelodysplastic syndrome, myelofibrosis, bone marrow metastasis
- Endocrine - EPO deficiency, hypothyroidism
- Anaemia of chronic disease (infection / inflammation / malignancy)
- Sideroblastic anaemia
- Thalassaemias
Increased RBC Destruction (Haemolysis)
- Immune haemolysis - autoimmune, alloimmune, drug-induced
- Red cell fragmentation - thrombotic microangiopathies, mechanical haemolysis
- Intrinsic RBC disorders - enzymopathies, membranopathies, haemoglobinopathies
- Hypersplenism
- Other - infection, copper, lead, hypophosphataemia
RBC Loss
- Trauma
- Gastrointestinal bleed
- Bleeding from another source e.g. urinary tract
Factitious
- Dilutional - excess fluid administration, pregnancy
Microcytic Hypochromic Anaemia
Look For
- Reduced serum haemoglobin, haematocrit and red cell count
- Reduced MCV (<80fL)
- Reduced MCH / MCHC
Causes of Microcytic Hypochromic Anaemia
- Iron deficiency anaemia
- Thalassaemia
- Congenital sideroblastic anaemia
- Anaemia of chronic disease
- Lead poisoning
- Hyperthyroidism
Normocytic Normochromic Anaemia
Look For
- Reduced serum haemoglobin, haematocrit and red cell count
- Normal MCV (80 - 100fL)
- Normal MCH / MCHC
Causes of Normocytic Normochromic Anaemia
- Dilutional - excess fluid administration, pregnancy
- Acute haemorrhage
- Chronic kidney disease
- Anaemia of chronic disease (infection / inflammation / malignancy)
- Pure red cell aplasia - Diamond-Blackfan syndrome, drugs, lymphoma, CLL, parvovirus B19
- Bone marrow infiltration - myelofibrosis, bone marrow metastases
- Early megaloblastic anaemia
- Early iron deficiency anaemia
- Haemolytic anaemia
- Congenital sideroblastic anaemia
Macrocytic Hyperchromic Anaemia
Look For
- Reduced serum haemoglobin, haematocrit and red cell count
- Elevated MCV (>100fL)
- Elevated MCH / MCHC
Causes of Macrocytic Hyperchromic Anaemia
- Megaloblastic anaemia - B12 / folate deficiency, drugs
- Myelodysplastic syndrome
- Post splenectomy
- Hypothyroidism
- Chronic liver disease
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