Overview of Anaemias

Question 1

Define anaemia.

Answer 1

Reduced blood haemoglobin concentration in relation to age, gender, physiological state, altitude.

Question 2

What are the NZ reference ranges for female and male.

Answer 2

Female: 115 - 155 g/L
Male: 130 -175 g/L

Question 3

Name the different types and values associated to each anaemia.

Answer 3

Mild: > 100g/L
Moderate: 70 - 100 g/L
Severe: < 70 g/L

Question 4

List the patient symptoms of anaemia.

Answer 4

Mild - often none
Weakness, fatigue 
Short of breath
Heart racing, palpitations 
Pounding in head/headache 
Pallor of mucus membranes 
Feel cold 
If vascular disease is present - angina (ischaemic heart muscle pain, claudication - ischaemic leg pain)

Question 5

List the clinical examination symptoms of anaemia.

Answer 5

Pallor of mucus membranes
Increased pulse rate
Severe anaemia - pulse rate increased, retinal haemorrhages, heart failure
Severe anaemia with co-existing vascular disease - myocardial ischaemia in ECG/exercise test, confusion - brain failure due to inadequate oxygen delivery

Question 6

When examining blood screen data, what morphological changes need to be looked at?

Answer 6

Hb normal/reduced/raised? (normal/anaemia/polycythaemia)
Cell size normal? (microcytic/normocytic/macrocytic)
Hb content of red cells normal?
(hypochromic/normochromic)

Question 7

Name the 3 patterns that are recognized as common forms of anaemia.

Answer 7

Hypochromic, microcytic
Normochromic, normocytic
Normochromic, macrocytic

Question 8

Name the two patterns that do not commonly occur, but may occur as variants of hypochromic microcytic and normochromic normocytic anaemias.

Answer 8

Normochromic microcytic

Hypochromic normocytic

Question 9

Name the classification of causes of anaemia.

Answer 9

Blood loss, followed by haemodilution - acute trauma, surgery
Impaired red cell production - disturbance of maturation of erythroblasts
- deficiencies of iron, folate, vitamin B12
- globin abnormalities
- disturbances of bone marrow/stem cell proliferation
Haemolysis - increased rate of RBC breakdown
- inherited: cell membrane, cell enzymes, some Hb abnormalities
- acquired (heterogenous) - antibodies (auto or allo), chemical damage, parasites (malaria), burns, chemical/drug etc

Question 10

What forms the haem of haemoglobin?

Answer 10

Iron + Protoporyhyrin

Question 11

What forms haemoglobin?

Answer 11

Haem + 2 alpha + 2 beta globin peptides

Question 12

What causes erythroid hypoplasia?

Answer 12

Marrow failure, reduced erythropoietin e.g. renal failure, reticulocytes low

Question 13

What causes haemolytic anaemia?

Answer 13

Shortened cell survival with secondary erythroid hyperplasia i.e. reticulocytes increased

Question 14

What causes ineffective erythropoiesis?

Answer 14

Megaloblastic anaemia, reticulocytes, usually normal or mildly increased; many erythroblasts destroyed in marrow due to metabolic abnormalities arising in erythropoiesis

Question 15

What are the causes of microcytic hypochromic anaemias?

Answer 15

Iron deficiency
- unable to make normal amounts of Hb
- reduced concenentration of Hb in red cells
- small, red cells that only have a low concentration of Hb
Thalassemias
- reduced production of alpha/beta globin peptide
- reduced concentration of Hb in red cells
- small red cells
Other causes are rare

Question 16

Discuss the causes of macrocytic anaemias.

Answer 16

Megaloblastic anaemia

• delayed & abnormal maturation of all cells in the bone marrow & other tissues
• caused by deficiency of vitamins needed for nucleic acid metabolism
• folic acid & vit B12 are needed for thymidine synthesis
• many dividing cells die due to DNA copying errors during mitosis - caused by lack of nucleotides
• deficiency affects all tissues but blood abnormalities are the usual means for diagnosis
• megaloblastic marrow maturation due to folic acid or vit B12 deficiency

Question 17

Discuss the causes of macrocytic anaemias. (megaloblastic)

Answer 17

Megaloblastic anaemia

• delayed & abnormal maturation of all cells in the bone marrow & other tissues
• caused by deficiency of vitamins needed for nucleic acid metabolism
• folic acid & vit B12 are needed for thymidine synthesis
• many dividing cells die due to DNA copying errors during mitosis - caused by lack of nucleotides
• deficiency affects all tissues but blood abnormalities are the usual means for diagnosis
• megaloblastic marrow maturation due to folic acid or vit B12 deficiency

Question 18

Discuss the causes of macrocytic anaemias (non-megaloblastic)

Answer 18

Liver disease
- Increased cholesterol in red cell membrane - cells become larger
Marked increased in red cell production
- Haemolytic anaemias
- Younger red cells are larger, as red cells age they lose cell membrane and become smaller
- average cell size increases
Others
- Myelodysplasia - a premalignant condition that is common in the elderly
- others = uncommon

Question 19

Discuss the causes of normochromic normocytic anaemia.

Answer 19

A large & heterogenous collection of anaemias

• Blood loss followed by haemodilution
• Anaemia of chronic disease (ACD) = secondary feature of an underlying disorder - chronic inflammation or cancer
• Anaemia of renal failure
• Anaemia in liver disease
• Haemoglobinopathies
• Haemolytic anaemias

Question 20

Discuss anaemia after haemorrhage.

Answer 20

Bleeding causes a reduced blood volume.
- blood pressure in venules (and capillaries) falls
- net movement of fluid into vessels from tissues
- normally a balance exists across blood vessels wall
IV infusion of fluids and kidneys retain salt and water over several days
- replaces fluid in tissues
Outcome: fall in Hb concentration
- time: most occurs in first 24hrs, completed by 72 hours

Question 21

Describe anaemia of chronic disease.

Answer 21

Normocytic normochromic
Tendency to microcytosis
- Mild to moderate anaemia: Hb above 90g/L
Main cause: Change in iron availability - low serum iron
- caused by liver release of a peptide - hepcidin
- reduced release of iron from stores: liver cells and macrophages of marrow, liver and spleen
- does not respond to iron therapy
- anaemia resolves if underlying condition settles
Frequency: very common