MACROCYTIC & OTHER HAEMOLYTIC ANAEMIAS
ANAEMIA
A condition that is used as a class name for a set of pathologies that all produce the
same RBC abnormality
Hb level below the reference range for that person’s age & gender
Erythrocytes are ~6 – 8μm in diameter bigger than some capillaries
(SO, need to be able to bend)
o LARGER THAN NORMAL ERYTHROCYTES problem
FRAGILE
do not bend easily break open as pass through capillaries
o release Hb into plasma (“HAEMOLYTIC ANAEMIA”)
becomes oxidised in plasma
MEAN RBC SIZE 96 fL (MCV: >96 fl macrocytic/megaloblastic anaemia)
, MACROCYTIC ANAEMIAS
MEGALOBLASTIC ANAEMIAS
o Affect DNA synthesis during erythropoiesis causes retarded development of
nucleus in relation to maturation of cytoplasm
o Cell division delayed
o Erythroblasts continue to grow form MEGALOBLASTS (larger RBCs)
o EXAMPLES:
Vitamin B12 or B9 deficiency
Drugs interfering with DNA synthesis (e.g., anti-cancer)
Some erythroid leukaemias
MACRONORMOBLASTIC ERYTHROPOIESIS
o Normal relationship between development of nucleus & cytoplasm BUT
erythroblasts are larger than normal
o EXAMPLES:
Liver disease
Alcohol toxicity
Some myelodysplastic syndromes
“STRESS” ERYTHROPOIESIS (or pseudo…(something))
o Conditions associated with high reticulocyte count (reticulocytes larger than RBCs)
o High level of EPO unexplained & accelerated erythropoiesis
o EXAMPLES:
Recovery from blood loss due to haemorrhage
Recovery from haemolytic anaemia
VITAMIN B9 or FOLATE
Water soluble
Synthesised in bacteria & plants
o abundant in green leafy vegetables (“foliage”), citrus & avocados
Absorption in DUODENUM & JEJUNUM
Converted to tetrahydrofolate (FH4) by intestinal cells (by dihydrofolate reductase)
Taken up by liver (stored for 3 – 4 months)
Provides carbons for other reactions (co-enzyme)
Used in nucleotide synthesis required for DNA & RNA synthesis
ANAEMIA
A condition that is used as a class name for a set of pathologies that all produce the
same RBC abnormality
Hb level below the reference range for that person’s age & gender
Erythrocytes are ~6 – 8μm in diameter bigger than some capillaries
(SO, need to be able to bend)
o LARGER THAN NORMAL ERYTHROCYTES problem
FRAGILE
do not bend easily break open as pass through capillaries
o release Hb into plasma (“HAEMOLYTIC ANAEMIA”)
becomes oxidised in plasma
MEAN RBC SIZE 96 fL (MCV: >96 fl macrocytic/megaloblastic anaemia)
, MACROCYTIC ANAEMIAS
MEGALOBLASTIC ANAEMIAS
o Affect DNA synthesis during erythropoiesis causes retarded development of
nucleus in relation to maturation of cytoplasm
o Cell division delayed
o Erythroblasts continue to grow form MEGALOBLASTS (larger RBCs)
o EXAMPLES:
Vitamin B12 or B9 deficiency
Drugs interfering with DNA synthesis (e.g., anti-cancer)
Some erythroid leukaemias
MACRONORMOBLASTIC ERYTHROPOIESIS
o Normal relationship between development of nucleus & cytoplasm BUT
erythroblasts are larger than normal
o EXAMPLES:
Liver disease
Alcohol toxicity
Some myelodysplastic syndromes
“STRESS” ERYTHROPOIESIS (or pseudo…(something))
o Conditions associated with high reticulocyte count (reticulocytes larger than RBCs)
o High level of EPO unexplained & accelerated erythropoiesis
o EXAMPLES:
Recovery from blood loss due to haemorrhage
Recovery from haemolytic anaemia
VITAMIN B9 or FOLATE
Water soluble
Synthesised in bacteria & plants
o abundant in green leafy vegetables (“foliage”), citrus & avocados
Absorption in DUODENUM & JEJUNUM
Converted to tetrahydrofolate (FH4) by intestinal cells (by dihydrofolate reductase)
Taken up by liver (stored for 3 – 4 months)
Provides carbons for other reactions (co-enzyme)
Used in nucleotide synthesis required for DNA & RNA synthesis
