HAEMATOLOGY REVISION
Globin chains % in adult blood % in foetal blood
HbA ɑ2β2 97 10-50
HbA2 ɑ2δ2 2.5 Trace
HbF ɑ2ɣ2 0.5 50-90
MICROCYTIC ANAEMIA
Iron deficiency anaemia
- Microcytic hypochromic anaemia
- Causes: blood loss (younger menorrhagia, older GI bleeding), poor diet or poverty
(children), malabsorption (Coeliac disease), hookworm (tropics)
- Sx: fatigue, koilonychia, atrophic glossitis, angular cheilosis, Plummer-Vinson syndrome
- Plummer-Vinson syndrome - oesophageal webs + iron deficiency anaemia +
glossitis; increased risk of SSC oesophagus
- Dx: bloods (FBC), haematinics (iron, folate, vit B12), blood film (anisocytosis,
poikilocytosis, pencil cells), endoscopy + colonoscopy, coeliac serology (tTG)
- Hb low, MCV low, MCH low, iron low, ferritin low, transferrin high
- Hb low and MCV low, in parallel
- Tx: ferrous sulphate 200mg/8h continued for >3mo after Hb normalises
Thalassaemia
, - Microcytic hypochromic anaemia
- AR, mutations in ɑ-globin chains cause ɑ-thalassaemia (Asian and African) and β-globin
chains cause β-thalassaemia (Mediterranean)
- ɑ-thalassaemia (deletion in HBA1 and HBA2 genes on ch16) - HbH (β4) and Hb
Barts (ɣ4) are formed
- β-thalassaemia (point mutation in HBB gene on ch11) - HbF (ɑ2ɣ2) is formed
- Provides partial resistance against malaria
- Sx: failure to thrive, splenomegaly (later hepatosplenomegaly), bone hypertrophy
(extramedullary haematopoiesis)
- Dx: bloods (FBC), haematinics (iron, folate, vit B12), blood film (Heinz bodies, target cells),
haemoglobin electrophoresis, DNA testing
- Hb low, MCV very low, MCH low, iron normal, ferritin normal, transferrin normal
- Hb low and MCV very low, not in parallel
- Tx: blood transfusions + deferoxamine
Sideroblastic anaemia
- Microcytic hypochromic anaemia
- Bone marrow produces ringed sideroblasts (nucleated RBCs, which are usually
precursors to mature RBCs) which cannot incorporate iron
- Can be congenital or acquired:
- Acquired clonal - part of myelodysplastic syndrome
- Acquired reversible - alcohol, isoniazid (pyridoxine (vit B6) deficiency)
- Dx: bloods (FBC, iron studies), blood smear (basophilic RBC stippling, Pappenheimer
bodies), bone marrow aspirate (sideroblasts)
- Tx: pyridoxine and blood transfusions ± deferoxamine (to prevent haemosiderosis)
NORMOCYTIC ANAEMIA
Sickle cell disease
- Normocytic normochromic anaemia
- AR, substitution in HBB gene on ch11 (glu → val at position 6) causes HbS instead of HbA
production (African)
- Heterozygotes - sickle-cell trait, HbAS; homozygotes - sickle-cell anaemia, HbSS
- Provides partial resistance against malaria
- Sx:
- Vaso-occlusive ‘painful’ crisis - microvascular occlusion causing dactilitis (seen
in <3y), mesenteric ischaemia, AVN, leg ulcers, CNS ischaemia
- Aplastic crisis - acute worsenings of baseline anaemia due to parvovirus B19
- Sequestration crisis - vascular occlusion of the liver or spleen causing acute
painful hepatosplenomegaly (seen in children)
- Acute chest syndrome - vascular occlusion of the lungs due to pulmonary be
infiltrates, vaso-occlusive ‘painful’ crisis often occurs before or during
Globin chains % in adult blood % in foetal blood
HbA ɑ2β2 97 10-50
HbA2 ɑ2δ2 2.5 Trace
HbF ɑ2ɣ2 0.5 50-90
MICROCYTIC ANAEMIA
Iron deficiency anaemia
- Microcytic hypochromic anaemia
- Causes: blood loss (younger menorrhagia, older GI bleeding), poor diet or poverty
(children), malabsorption (Coeliac disease), hookworm (tropics)
- Sx: fatigue, koilonychia, atrophic glossitis, angular cheilosis, Plummer-Vinson syndrome
- Plummer-Vinson syndrome - oesophageal webs + iron deficiency anaemia +
glossitis; increased risk of SSC oesophagus
- Dx: bloods (FBC), haematinics (iron, folate, vit B12), blood film (anisocytosis,
poikilocytosis, pencil cells), endoscopy + colonoscopy, coeliac serology (tTG)
- Hb low, MCV low, MCH low, iron low, ferritin low, transferrin high
- Hb low and MCV low, in parallel
- Tx: ferrous sulphate 200mg/8h continued for >3mo after Hb normalises
Thalassaemia
, - Microcytic hypochromic anaemia
- AR, mutations in ɑ-globin chains cause ɑ-thalassaemia (Asian and African) and β-globin
chains cause β-thalassaemia (Mediterranean)
- ɑ-thalassaemia (deletion in HBA1 and HBA2 genes on ch16) - HbH (β4) and Hb
Barts (ɣ4) are formed
- β-thalassaemia (point mutation in HBB gene on ch11) - HbF (ɑ2ɣ2) is formed
- Provides partial resistance against malaria
- Sx: failure to thrive, splenomegaly (later hepatosplenomegaly), bone hypertrophy
(extramedullary haematopoiesis)
- Dx: bloods (FBC), haematinics (iron, folate, vit B12), blood film (Heinz bodies, target cells),
haemoglobin electrophoresis, DNA testing
- Hb low, MCV very low, MCH low, iron normal, ferritin normal, transferrin normal
- Hb low and MCV very low, not in parallel
- Tx: blood transfusions + deferoxamine
Sideroblastic anaemia
- Microcytic hypochromic anaemia
- Bone marrow produces ringed sideroblasts (nucleated RBCs, which are usually
precursors to mature RBCs) which cannot incorporate iron
- Can be congenital or acquired:
- Acquired clonal - part of myelodysplastic syndrome
- Acquired reversible - alcohol, isoniazid (pyridoxine (vit B6) deficiency)
- Dx: bloods (FBC, iron studies), blood smear (basophilic RBC stippling, Pappenheimer
bodies), bone marrow aspirate (sideroblasts)
- Tx: pyridoxine and blood transfusions ± deferoxamine (to prevent haemosiderosis)
NORMOCYTIC ANAEMIA
Sickle cell disease
- Normocytic normochromic anaemia
- AR, substitution in HBB gene on ch11 (glu → val at position 6) causes HbS instead of HbA
production (African)
- Heterozygotes - sickle-cell trait, HbAS; homozygotes - sickle-cell anaemia, HbSS
- Provides partial resistance against malaria
- Sx:
- Vaso-occlusive ‘painful’ crisis - microvascular occlusion causing dactilitis (seen
in <3y), mesenteric ischaemia, AVN, leg ulcers, CNS ischaemia
- Aplastic crisis - acute worsenings of baseline anaemia due to parvovirus B19
- Sequestration crisis - vascular occlusion of the liver or spleen causing acute
painful hepatosplenomegaly (seen in children)
- Acute chest syndrome - vascular occlusion of the lungs due to pulmonary be
infiltrates, vaso-occlusive ‘painful’ crisis often occurs before or during
