Anaemia Intro/ Microcytic Anaemia

Question 1

what is anaemia

Answer 1

reduced total red cell mass

haemoglobin concentration is a surrogate as is haematocrit

Question 2

what Hb levels mean anaemia in males and females

Answer 2

adults males Hb <130

adult females Hb <120

Question 3

what is metHb

Answer 3

haemoglobin with Fe3+ instead of Fe2+ (oxidised)

Question 4

how do you measure haematocrit

Answer 4

as a ratio of the whole blood the is redd cells if the sample was left to settle

it is a percentage eg. 50% or 0.5

not commonly used now

Question 5

when are Hb/hct not good markers of anaemia

Answer 5

someone with rapid large blood loss (because blood is lost but it hasn’t yet been diluted by plasma to make up the volume)

haemodilution - giving someone fluid overnight to increase their plasma volume causing an anaemia

Question 6

how does the body respond to anaemia

Answer 6

making more red cells

1. reticulocytosis - making reticulocytes

Question 7

what are reticulocytes

Answer 7

red cells that have just left the bone marrow- larger than average red cells

still have remnants of protein making so stain purple/deeper red

takes a few days in response to anaemia

Question 8

what can we measure

Answer 8

Hb concentration
Number of red cells
Size of red cells

Question 9

what can we calculate

Answer 9

haematocrit
mean cell Hb
mean cell Hb concentration

Question 10

what other investigations can be done (RBCs)

Answer 10

blood film (look at cellular morphology)

reticulocyte count (assesses marrow response)

additional tests depending on findings

Question 11

what are the pathophysiological classifications of anaemia

Answer 11

Decreased production (low reticulocyte count)

increased loss or destruction of read cells (high reticulocyte count)

Question 12

causes of decreased production anaemia

Answer 12

hypoproliferative
-reduced erythropoiesis

maturation abnormality

• erythropoeisis present but ineffective
• can be cytoplasmic defects (impaired haemoglobinisation)
• can be nuclear (impaired cell division)

Question 13

causes of increased loss/destruction anaemia

Answer 13

bleeding

haemolysis

Question 14

classifications of anaemia based on morphology

Answer 14

Microcytic

• MCV is low
• consider problems with haemoglobinisation

Macrocytic

• MCV is high
• consider problems with maturation

Question 15

where doesn’t haemoglobin synthesis occur

Answer 15

cytoplasm

Question 16

consequences of defects in haemoglobin synthesis

Answer 16

microcytic hypochromic anaemia

small cells without colour due to no haem

Question 17

causes of microcytic hypochromic anaemia

Answer 17

iron deficiency
problems with porphyrin synthesis - v rare
lead poisoning - rare
anaemia of chronic disease -rare

Globing deficiency
-thalassaemia

Question 18

what is iron essential for

Answer 18

oxygen transport
-Hb, myoglobin

Electron transport
-mitochondrial production of ATP

Question 19

how much iron is absorbed per day (without treatment)

Answer 19

1mg/day

Question 20

how much iron is circulating in the plasma and how much in marrow

Answer 20

4mg

150mg in marrow

Question 21

what is iron stored in

Answer 21

ferritin

macrophage stores and liver stores

however most of iron at one time is in Hb

Question 22

what tests can be done to check iron status

Answer 22

functional iron - Hb

transported iron - serum iron, transferrin, transferrin saturation

storage iron - serum ferritin

Question 23

what is transferrin

Answer 23

protein which binds two iron molecules

transports from donor tissues (macrophages, hepatocytes, intestinal cells) to tissues expressing transferrin receptors (eg. erythroid marrow)

transferrin saturation reflects iron supply

• reduced in iron deficiency
• reduced in anaemia of chronic disease
• increased in genetic haemachromotosis

Question 24

what is ferritin

Answer 24

large intracellular protein

spherical protein which stores up to 4000 ferric ions

tiny amount of ferritin present in serum which reflects intracellular ferritin synthesis in response to iron status

serum is an easy measurement of storage iron

low ferritin ALWAYS means iron deficiency

produced only if there is iron to store

Question 25

how do you confirm iron deficiency anaemia diagnosis

Answer 25

decreased functional iron and reduced iron storage (serum ferritin)

Question 26

causes of iron deficiency

Answer 26

not eating enough iron:
relative deficiency
-women of child bearing age and children

absolute deficiency
-vegetarian diets
v unlikely in men

Losing too much iron (blood loss)

not absorbing enough iron (coeliac disease, achlorhydria)

Question 27

causes of chronic blood loss causing iron deficient anaemia

Answer 27

Menorrhagia
GI
-tumours, ulcers, NSAIDs
Haematuria

Question 28

what is normal menstrual blood loss

Answer 28

30-40ml/month

equivalent to 15-20mg/month of iron

heavy menstrual loss >60ml is >30mg of iron a month of iron lost

Question 29

consequences of iron deficient anaemia

Answer 29

• exhaustion of iron stores
  -iron deficient erythropoiesis
  -microcytic anaemia
  -epithelial changes
  (skin, koilonychia)

Question 30

treatment for iron deficiency anaemia

Answer 30

iron replacement therapy to relieve symptoms

investigations to work out underlying cause

early GI surgery can be curative