Clinical approach to patient with anaemia

Question 1

Anaemia defintion

Answer 1

reduced Hb for age and sex of patient

therefore reduced O2 carriage to tissues

Question 2

Classification of anaemia

Answer 2

pathogenic i.e. reduced production versus increased loss (bleeding haemorrhage)
Morphological: micro and macrocytic

Question 3

Haemoglobin vs red cell values

Answer 3

usually haemoglobin and red cell counts both decrease
Occasionally in hypochromic and microcytic anaemia of iron deficiency red cell count is normal although Hb is reduced, due to low Hb content of individual cells

Question 4

anaemia results form one of 3 fundamental disturbances

Answer 4

impaired red cell formation by bone marrow
blood loss
excess red cell destruction (hemolysis)

Question 5

Morphological classification based on

Answer 5

Red cell appearance under the microscope
MCV = mean red cell volume
MCHC = mean cell haemoglobin concentration

Question 6

Normocytic anemia

Answer 6

MCV in normal range, most are also normochromic with normal MCHC, but in some mild hypochromia

Question 7

Hypo chromic microcytic anemias

Answer 7

MCV and MCHC reduced

Question 8

Macrocytic anemias

Answer 8

MCV increased, most normochromic some hypo chromic

Question 9

Two steps in the clinical investigation of anaemia

Answer 9

determination of the morphological type

determination of the cause

Question 10

Causes of impaired production

Answer 10

deficiency of substances essential for red cell production
- iron, vit B12, folate
Genetic defect in red cell production
- thalassaemia
Failure of bone marrow
- infiltration e.g. leukaemia, irradiation or drug damage

Question 11

Causes of reduced red cell survival

Answer 11

Blood loss 
- usually acute e.g. trauma, surgery 
- note, slow, chronic blood loss gives rise to iron deficincy 
Haemolysis 
- shortened survival within the body 
- environmental or red cell problem

Question 12

Morphological approach to anaemia

Answer 12

uses MCV, MCHC and blood film

• microcytic hypochromic
• normocytic normochromic
• macrocytcic anemia

Question 13

Causes of microcytic hypo chromic anaemias

Answer 13

Iron deficiency
Chronic illness - iron block
genetic - thalassemia

Question 14

Explain anaemia of chronic inflammation

Answer 14

Iron block 
Mild anemia e.g. 90-100g/L 
iron studies = normal or raised ferritin 
low normal Fe 
Low normal TIBC 
normal saturation

Question 15

Diagnosis of iron deficiency

Answer 15

measure: serum iron, iron binding capacity/transferrin and iron saturation
measure serum ferritin
Rarely examine iron stores in bone marrow
NOTE: must identify the cause of iron deficiency
anemia occurs late in iron deficiency

Question 16

Causes of iron deficiency

Answer 16

Diet 
- veggie 
Malabsorption 
- prog small bowel 
Increased demands 
- pregnancy 
Chronic blood loss 
- GI or GU tract

Question 17

Investigations of iron deficiency based on age, gender and maturity status

Answer 17

Children - deficient dietary intake
Premenopausal women - imbalance between dietary intake of iron and menstrual blood loss usual cause, or repeat pregnancies
In males and post menopausal females, occult blood loss from GI tract

Question 18

Other causes of microcytic anaemia

Answer 18

Anaemia of chronic inflammation or disease - patient with underlying malignancy or inflammatory disease e.g. rheumatoid arthritis
thalassemia

Question 19

Macrocytic / megaloblastic anemia

Answer 19

vit B12 deficincy
Folate deficiency
- liver disease, hypothyroid, excess alcohol intake
if extremely severe folate or B12 deficincy it can affect other blood lineages, not only only anaemia, white cells and platelet counts can be reduced –> hyper segmented neutrophils

Question 20

Consequences of B12 / folate deficincy

Answer 20

impaired DNA synthesis
may affect all cell lineages if severe, but initially microcytic anaemia
Measure serum vitamin B12 and folate levels
As in iron deficiency need to determine cause of low B12 or folate level

Question 21

Causes of a low bit B12 level

Answer 21

Diet, uncommon (vegan) 
Malabsorption 
-gastrectomy 
-immune (pernicious anaemia, antibodies against parietal cells and or intrinsic factor)
-terminal ill disease 
body has stores for 3-4 year

Question 22

Diagnosis of iron deficiency

Answer 22

measure serum iron, iron binding capacity/ transferrin and iron saturation
Measure serum ferritin
rarely examine iron stores in bone marrow

Question 23

Hepsidin

Answer 23

transports iron from gut into circulation

Question 24

Causes of low folate level

Answer 24

Diet - lack of vegges
Malabsorption - e.g. coeliac disease (prog small bowel)
Increased demands or utilisation e.g. pregnancy

Question 25

Haemolytic anemia

Answer 25

due to increased rate of destruction of red cells
Clin features: pallor, mild jaundice, splenomegaly
Lab findings: features of increasing red cell destruction e.g. raised bilirubin, hepatoglobins
Features of increased red cell production e.g. reticulocytes
- damaged red cells
Classification of haemolytic anaemia
- intrinsic red cell defects usually hereditary e.g. membrane defect
- environmental, usually acquired e.g. autoimmune

Question 26

Iron deficiency treatment

Answer 26

Iron replacement therapy e.g. ferrogradument

Question 27

Thalassaemia

Answer 27

Mainly in malaria areas - africa and south east asia
- Heterozygote, mild anemia
- Homozygote, severe anemia
Lab diagnosis, hemaglobinopathy screen and in selected cases genetic testing