Anaemia

Question 1

Anaemia definition

Answer 1

Reduced total RBC mass

Question 2

How is RBC mass measured (indirectly)?

Answer 2

Haemoglobin concentration (or haematocrit concentration)

Question 3

Do male or females have higher haemoglobin?

Answer 3

Adult males typically have higher Hb than females

Question 4

How is Hb concentration measured

Answer 4

Using a spectrophotometric method (as Hb is red)

Question 5

How is haematocrit measured

Answer 5

Percentage of RBCs in blood

Question 6

In rare situations Hb/hct are not a good marker of anaemia. Name two examples of this?

Answer 6

Right after a rapid bleed - Hb is lower but so is plasma volume and therefore Hb/hct remains normal despite RBC loss

Right after treating dehydration - plasma volume increases and therefore Hb/hct increases despite no RBC loss

Question 7

What is the normal response to anaemia

Answer 7

Make more RBC => reticulocytosis

Question 8

What are reticulocytes and how are they different from average RBCs

Answer 8

Reticulocytes
- RBCs that have just left the bone marrow
- larger than mature RBCs
- Have RNA remnants & so stain purple/deeper read, blood film appears polychromatic

Question 9

What is the timeline for reticulocytosis after anaemia

Answer 9

• Initial burst may occur after acute haemorrhage
• But up regulation of production from anaemia takes a few days

Question 10

In anaemia, what does a low vs high reticulocyte count indicate

Answer 10

Low reticulocyte count (Decreased production)
- hypoproliferative anaemia (reduced erythropoiesis)
- maturation defect (ineffective erythropoiesis)
- cytoplasmic defects - impaired haemoglobinisation
- nuclear defects - impaired cell division

High reticulocyte count (Increased loss/destruction)
- Blood loss
- Haemolysis

Question 11

When can mean cell volume be useful

Answer 11

To distinguish between cytoplasmic (haemoglobin) and nucleur (cell division) maturation defects.

• Low MCV (microcytic) => cytoplasmic (haemoglobin)
• High MCV (macrocytic) => nucleur (cell division)

Question 12

Name the measured & calculated RBC indices given in a FBC

Answer 12

Measured RBC indices
- Hb concentration
- Number of RBCs
- Size of RBCs

Calculated RBC indices
- Haematocrit
- Mean cell Hb
- Mean cell Hb concentration

Question 13

Summarise the investigations used in anaemia diagnosis & classification

Answer 13

GENERAL (FIRST LINE) TESTS
- RBC, RBC indices & Hb levels
- Reticulocyte count (assess marrow response)
- Blood film (cellular morphology)
- Haematinics (serum B12/ Folate/ ferritin) (test for cause)

SPECIALISED TESTS
- Erythropoietin (assess kidney hypoxia feedback) (expensive)
- Bone marrow biopsy
- HbA2 levels
- Biochemistry tests e.g. LFTs for liver disease

Question 14

Anaemia general clinical presentation

Answer 14

• SOB, Fatigue, Headaches, Faintness
• Palpitations & Tachycardia
• Cause specific symptoms e.g. neurological effects in B12 deficiency anaemia, jaundice in macrocytic anaemia….

Question 15

Summarise the locations of absorption of folate, iron & B12

Answer 15

Folate absorption - Jejunum

Iron absorption - Duodenum & proximal jejunum

B12 absorption - Distal small bowel

Question 16

List some causes of physiological anaemia

Answer 16

• Neonatal (adjustment to life outside the uterus)
• Pregnancy (plasma increases so low Hb concentration despite normal amount)

Question 17

In what two types of neonates/children is iron deficiency anaemia more likely and why?

Answer 17

Preterms

(Stores from mum tend to happen in third trimester)

Babies breastfeed for more than 6 months

(Stores from mum run out & breast milk does not contain Fe)

Question 18

If you see RBCs with nuclei on blood film, what are the three possible causes?

Answer 18

• Physiological in newborns
• Increased hypoxic drive & fast reticulocyte production
• RBC precursors being pushed into blood (e.g. bone marrow malignancy)

Question 19

Why do Hb need to be in RBCs and not free in blood

Answer 19

• Decreases viscosity
• Protects Hb
• More efficient