Intro to anaemia and microcytic anaemia

Question 1

What is the definition of anaemia?

Answer 1

Reduced total red cell mass; use Hb concentration as a surrogate marker
Can also use haematocrti

Question 2

What are the cut offs for anaemia?

Answer 2

Adult males; Hb <130 g/L, Hct 0.38-0.52

Adult females; Hb <120 g/L, Hct 0.37-0.47

Question 3

How is Hb conc measured using a spectrophotometric method?

Answer 3

Lyse red cells to create Hb solution
Stabilise Hb molecules
Measure optical density at 540 nm
Hb conc calculated against known reference standard conc solution

Question 4

What is beer’s law?

Answer 4

Optical density is proportional to the concentration of Hb

Question 5

What is Hb/hct not a good marker of anaemia?

Answer 5

Rapid exsanguination

Haemodilution

Question 6

What is the normal response to anaemia?

Answer 6

Increased red cell production - reticulocytosis

Question 7

What are reticulocytes?

Answer 7

Red cells that have just left the bone marrow
Larger than average red cells
Still have RNA
Stain purple/ deeper red as a consequence
Blood film appears polychromatic

Question 8

Why does polychromasia result in reticulocytes?

Answer 8

Residual RNa in the cell gives the classic blue-grey appearance

Question 9

How is haematocrit calculated?

Answer 9

Red cell number x red cell size

Question 10

What is the purpose of the blood film?

Answer 10

Cellular morphology

Question 11

What does the reticulocyte count assess?

Answer 11

Marrow response

Question 12

How can anaemia be classified on pathophysiological terms?

Answer 12

Decreased production (low retic count)
Increased loss or destruction of red cells (high retic count). Bleeding or haemolysis
Redistribution - (splenomegaly)
Decreased production (low retic count) :
Hypoproliferative - reduced amount of erythropoiesis
Maturation abnormality - erythropoiesis present but ineffective (cytoplasmic defects - impaired hemoglobinization. Nuclear defects - impaired cell division)

Question 13

How can MCV determine the type of anaemia?

Answer 13

Low (microcytic) = issue with haemoglobinisation

High (macrocytic) = nuclear maturation

Question 14

Where does haemoglobin synthesis occur in the cell?

Answer 14

Cytoplasm

Question 15

Where is haem synthesized in the cell?

Answer 15

Mitochondrion

Question 16

What makes up haem?

Answer 16

Porphyrin ring

Iron (Fe 2+)

Question 17

What does iron deficiency anaemia present like?

Answer 17

Microcytic hypochromic anaemia: deficient haemoglobin synthesis (cytoplasmic defect)

Question 18

What are the causes of hypochromic microcytic anaemia?

Answer 18

Haem deficiency: 
Iron deficiency 
Porphyrin synthesis (lead poisoning) 
Congenital sideroblastic anaemia 
Globin synthesis deficiency - thalassaemia (trait, intermedia, major)

Question 19

What is the function of iron?

Answer 19

Oxygen transport (Hb, myoglobin) 
Electron transport (mitochondrial production of ATP)

Question 20

In a normal patient (not on supplements), how much iron is absorbed per day?

Answer 20

1mg/ day

Question 21

How much iron is stored in red cell Hb?

Answer 21

2500 mg

Question 22

How is iron transported around the body?

Answer 22

Transferrin

Question 23

How is iron stored in the liver and macrophages?

Answer 23

Ferritin

Question 24

How much iron can bind to transferrin?

Answer 24

2 binding sites

Question 25

What does the % saturation of transferrin measure?

Answer 25

Iron supply; low in iron deficiency anaemia and anaemia of chronic disease Increased in genetic haemochromatosis

Question 26

How much iron can a ferritin protein stor?

Answer 26

4000 ferric ions

Question 27

What is serum ferritin an indirect measure of?

Answer 27

Storage iron

Question 28

How can iron deficiency be confirmed?

Answer 28

Anaemia (decreased functional iron) and reduced storage iron (low serum ferritin)

Question 29

What can cause a relative iron deficiency?

Answer 29

Women of child bearing age Developing foetus Pregnant women

Question 30

What can cause an absolute iron deficiency?

Answer 30

Veggie/ vegan diets Blood loss Menorrhagia Coeliac disease, achlorhydria

Question 31

What can cause chronic blood loss?

Answer 31

Menorrhagia GI; tumour, ulcer, NSAIDs Haematuria

Question 32

What is defined as heavy menstrual blood loss?

Answer 32

>60ml i.e. >30mg iron/month

Question 33

What are the sequential consequences of a negative iron balance?

Answer 33

Exhaustion of iron stores Iron deficient erythropoiesis; falling red cell MCV Microcytic anaemia Epithelial changes; dry skin, koilonychia

Question 34

Is iron deficiency anaemia a diagnosis?

Answer 34

No; a symptom. Need to determine why there is iron deficiency