1. Failure of red cell production
Dr Dupe Elebute
Consultant Haematologist

2. Aim To revise the process and control of normal erythropoiesis
To discuss the mechanisms of failure of red cell production

3. Overview Origin and control of red cell production
Role of iron in haemoglobin structure and function
Role of vitamin B12 and folic acid in red cell production
Other causes of failure of red cell production

4. Erythropoiesis
Erythropoiesis is the process of red blood cell production
Erythrocytes are derived from the division and differentiation of a common stem cell precursor

5. Erythropoiesis: earliest stages
BFU-E (day 3), CFU-E (day 7), immature erythroblast (day 11) and mature erythroblast (day 15). Romanowsky stain.

10. Erythropoietin Haemopoietic growth factor
Main control of rbc production
Produced in the kidney
Released by low O2 tension (hypoxia, anaemia)
Reacts with Epo receptors on red cell
precursors to increase rbc production
Recombinant Epo available (anaemia due to
renal failure)

11. Haematinics Dietary substances
Essential for production of red blood cells and Hb
Most important:
Iron
Vitamin B12
Folic acid

12. Anaemia Reduced haemoglobin level
Normal range depends on age and gender
Subclassified by red cell indices
Microcytic, hypochromic
Normocytic, normochromic
Macrocytic

13. Microcytic, hypochromic anaemia
Definition:
Caused by defective synthesis of Hb, resulting in red cells that are smaller than normal (microcytic) and contain reduced amounts of haemoglobin (hypochromic).
Differential diagnosis:
Iron deficiency anaemia
Thalassaemia
Sideroblastic anaemia

14. Iron Function Dietary source Major role in several metabolic processes
Combines with protoporphyrin ring to form haem
Four haem groups to each tetramer of Hb
1g of Hb can combine with 1.34ml of O2
Dietary source
Present in food as ferric hydroxide
Red meat best source

15. Iron Daily dietary iron requirements per 24 hours: Male 1 mg
Adolescence
2-3 mg
Female (reproductive age)
Pregnancy
3-4 mg
Infancy
Maximum bioavailability from normal diet about
4 mg

16. Iron Absorption Transport Occurs in duodenum and jejunum
Enhanced by acid and reducing agents
1-2mg (5-10%) absorbed daily
Transport
In plasma combined with transferrin
Combined with apoferritin in RES
Stored as ferritin

17. Iron deficiency anaemia (IDA)
inadequate intake of iron
dietary deficiency
Malabsorption
increased loss of iron
menorrhagia
gastro-intestinal bleeding
haematuria
increased need for iron
Pregnancy and lactation
Barium meal showing hiatus hernia causing IDA

18. IDA: signs and symptoms
Rapidly progressive anaemia usually causes more symptoms
Some people with severe anaemia have no symptoms at all
Common symptoms of anaemia include:
Tiredness; Fatigue
Pale appearance
Irritability; Headache
Reduced exercise capacity
Palpitations

19. IDA: signs and symptoms (2)
Severe and prolonged deficiency may produce the following symptoms:
Painless glossitis (tongue smooth and red)
Curling and softening of the nails (spooning; koilonychia)
Brittle hair
Pica ( unusual dietary cravings)
Nail changes in iron deficiency anaemia (koilonychia)

20. IDA: diagnosis Blood tests (FBC): Low Hb, MCV and MCH Blood film:
the red blood cells are smaller (microcytic) than usual and paler in colour (hypochromic). Some of the red cells may have an abnormal shape (poikilocytosis; pencil cells)
Platelet count may be raised

21. Normal blood film
Hypochromic, microcytic picture with marked anisocytosis and poikilocytosis

22. IDA: diagnosis (2) Iron studies Serum iron: low (10-30μmol/l)
Total iron binding capacity: high (50-70μmol/l)
Transferrin saturation: low (>16%)
Serum Ferritin level: low (12-150μg/l)
best indicator of body iron status; when <12μg/l, indicates iron deficiency!

23. Iron stores in the bone marrow: The marrow smear is treated with potassium ferricyanide (Prussian blue) which stains the iron within the reticulo-endothelial cells blue.
Reduced iron stores
Normal iron stores

24. Differential diagnosis of a hypochromic anaemia
IDA
Anaemia
of chronic disorder
Thalassaemia trait
Sideroblastic anaemia
MCV, MCH, MCHC
All 
in relation to anaemia
Low normal
or mild reduction
Very low for degree of anaemia
 congenital
 Acquired
Serum iron  N 
TIBC
Serum ferritin
N/
BM iron stores
Absent
Present

25. IDA:further investigations
Dietary history
Drug history: Aspirin, other anti-inflammatory
Menstrual history
Exclude GI tract malignancy
faecal occult blood (checks faeces for microscopic amounts of blood)
colonoscopy (tube test to look at the large bowel);
gastroscopy. (tube test to look at gullet and stomach).

26. IDA: treatment Treat underlying cause
Oral iron: Ferrous sulphate (67mg per 200mg tablet)
Cheap!
Treat for up 4-6 months to correct anaemia and replenish stores
Hb rise of about 2g/dl every 3 weeks
S/E include nausea, diarrhoea, constipation
Reduce dose or use preparation with lower iron content .e.g. Ferrous gluconate (37mg per 300mg tablet
Ferrous succinate, lactate, fumarate: more expensive

27. IDA: treatment
Parenteral iron rarely used as allergic reactions, anaphylaxis quite common
Preparations of iron dextran or iron-sorbitol-citrate given intramuscularly (I.M) or intravenously (I.V)
Iron dextran can be given I.V in total dose infusion
NB: Blood transfusion is rarely indicated and may be dangerous

28. Macrocytic anaemia Definition:
Rise in the mean cell volume of the red cells above the normal range (adults fl)
Differential diagnosis:
Reticulocytosis (acute bleeding)
Vitamin B12 or folate deficiency
Alcoholic liver disease
Hypothyroidism
Myelodysplasia (MDS)

29. Macrocytic anaemia: investigation
Clinical
Dietary history
GI symptoms
Alcohol consumption
Hypothyroidism (lethargy, weight gain)

30. Macrocytic anaemia: investigation
Blood film
Hypersegmented neutrophils (B12 def)
Target cells, stomatocytes (liver disease)
Abnormal morphology (MDS)

31. Blood film in vitamin B12 deficiency showing macrocytic red cells and a hypersegmented neutrophil.
Normal blood film

32. Macrocytic anaemia: investigation
Reticulocyte count
Liver and thyroid function tests
Serum B12 and folate assays
Bone marrow aspirate
Megaloblastic features
Alternative diagnosis (MDS, AA)

33. High power view of a normal bone marrow aspirate
Megaloblastic features in BMA
Megaloblastic BM: giant metamyelocytes

34. Vitamin B12 Source: Absorption: Only produced by micro-organisms
Mainly from animal produce
Stable to cooking
Absorption:
Mainly through the ileum
Combines with intrinsic factor (IF)
IF produced by gastric parietal cells
Complex combines with IF receptors in terminal ileum ―› B12 absorbed

35. Vitamin B12 deficiency Minimum daily requirement: 1-2μg
Body stores: 2-3mg (lasts for 2-4 yrs)
Deficiency caused by:
Malabsorption
Dietary lack (vegans)
Pernicious anaemia (antibodies directed against IF)
Blind-loop syndrome

36. Vitamin B12 deficiency (2)
Symptoms and signs:
Macrocytic, megaloblastic anaemia
Neurological symptoms – subacute combined degeneration of the cord
Glossitis due to Vitamin B12 deficiency

37. B12 deficiency: investigation
Radioactive vitamin B12 absorption with and without intrinsic factor (Schilling test)
Serum gastric parietal and intrinsic factor antibodies
Endoscopy–gastric biopsy (vitamin B12 deficiency), duodenal biopsy (folate deficiency)

38. B12 deficiency: treatment
Hydroxycobalamin: parenteral preparation only
Initial/loading dose of 1mg every 3-4 days for up to 6 doses
Maintenance dose of 1mg every 3 months

39. Folic Acid Source: Most foods esp meat (liver), vegetables, yeasts
Natural folates largely in the polyglutamate form
Easily destroyed by cooking
Absorption:
Polyglutamates deconjugated and converted to monoglutamate 5-methyltetrahydrofolate
Absorbed through duodenum and jejunum

40. Folic Acid Normal dietary intake 600-1000g
Daily requirement g
Body stores 10-12mg (enough for 4 months)
Deficiency caused by:
Inadequate dietary intake (lack of fresh veg!)
Malabsorption: coeliac disease, tropical sprue
Increased demands: pregnancy, proliferative disorders e.g. chronic haemolytic anaemia

41. Folate deficiency Symptoms and signs: Megaloblastic anaemia
Neural tube defects in fetus
No clear relation between maternal folate levels and defects but…
Folic acid supplements in early pregnancy shown to reduce incidence of spina bifida, anencephaly, cleft palate and hare lip

42. Folate deficiency Treatment: B12 deficiency must be excluded first
to prevent development/exacerbation of neurological disease
Oral folic acid: 5mg daily
Prophylaxis in pregnancy: 400g from time of conception

43. Bone marrow failure syndromes
Acquired/Idiopathic
Aplastic anaemia
Red cell aplasia
Acquired/Infection
Parvovirus B19
Congenital
Fanconi anaemia
Diamond Blackfan anaemia

44. Bone marrow trephine biopsy showing normal ratio of haemopoietic cells and fat spaces
Hypoplastic bone marrow
Aplastic bone marrow

45. More Information from:
Essential Haematology: Hoffbrand & Pettit
Lecture notes on Haematology: Hughes-Jones & Wickramasingh
ABC of clinical haematology: Provan