Lecture 6: Clinical Approach to the Patient with Anaemia Flashcards
What are 2 ways of classifying anaemia?
1) Basic mechanism
- Impaired production vs blood loss/haemolysis
2) Morphological
- Based on the appearance of the red cells
Describe the different physiological causes for Anaemia
1) Ineffective production
- Deficiency of s_ubstances essential for red cell production_
- e.g. iron, vit 12, folate
-
Genetic defect in red cell production
- e.g. thalassaemia
-
Failure of the bone marrow
- e.g. infiltration
- leukaemia
- irradiation
- drug damage
- e.g. infiltration
2) Impaired red cell survival
- _Blood Los_s
- Usually acute e.g. trauma, surgery
-
Haemolysis
- Shortened survival of the red cell (where the body breaks down RBC)
- Often jaundiced
- Shortened survival of the red cell (where the body breaks down RBC)
If someone is anemic and jaundiced, what type of anaemia is it likely to be?
Haemolytic Anaemia
(lots of breakdown of RBC, so build up of bilirubin)
Describe the Morphologic approach to anaemia
Uses mean cell volume, average cell Hb concentration and blood film comment
-
Microcytic hypochromic anaemia (MCV <76)
- Small RBC, pale anaemia
- Normochromic normocytic anaemia (MCV 76-96)
-
Macroytic anaemia (MCV>96)
- Large RBC
What are the Red Cell Values that we are interested in?
1) Haemoglobin: g/L
2) Red Cell Count
3) Haematocrit or Packed Cell Volume (% of Red cell volume to the whole blood volume)
4) Red Cell Absolute Values
- Mean cell volume
- Mean cell Hb
- Mean cell Hb concentration
What sort of investigations should you do to determine the cause of anaemia?
1) Red Cell values e.g. Hb, Red cell count, Haematocrit, Red cell absolute values
May also look at
2) WBC and platelet count
3) Reticulocyte
4) Examination of the blood film
5) Bone marrow examination
Describe Microcytic Hypochromic Anaemia
Caused when something intereferes with the haemoglobin production
RBC is pale and smaller.
1) Iron deficiency
2) Chronic Illness
- Iron block
3) Genetic
- Thalassaemia
Describe the causes of Microcytic anaemia
explain which part of the RBC each of the causes effects
Iron + Protoporphyrin -> Haem
Iron deficiency, or _chronic inflammatio_n or malignancy can result in less haem = Microcytic Hypochrommic Anaemia
Thalassemia affects the Globin part = Microcytic Hypochrommic Anaemia
How do you diagnose Iron Deficiency? (after finding out that someone has microcytic anaemia)
1) Measure serum iron, ir_on binding capacity (transferrin_), and iron stauration
- *see pic
- Blue(red dots) = Serum ion,
- All = Iron binding capacity/Transferrin level
- Normal
- Iron deficiency
- More transferrin and less ferritin than anaemia of chronic disorders
- Anaemia of chornic disorders
- Different to iron deficiency by looking at the low ferittin levels and the iron transport proteins
- Iron overload
2) Measure serum ferritin
- Soluble storage form of iron
- In iron deficiency, this will be low
3) Rarely examine iron stores in bone marrow
What are the different outcomes of Iron studies?
How can you tell by looking at the blood test if someone has normal, iron deficiency, anaemia of chronic disorders (inflammation) or iron overload?
- Blue = Serum Ion
- Pink = Iron binding proteins/Transferrin
- Green = Serum ferritin
- Normal
-
Iron deficiency
- More transferrin and less ferritin than anaemia of chronic disorders
-
Anaemia of chornic disorders (e.g. oestomylitis, arthritis)
- Lower transferrin and more ferritin than iron deficiency anaemia
-
Iron overload
- No Serum ion
- High ferritin
Explain this lab result
- HB = 50 (anaemia)
- MCV = 62 (mycrocytic)
- MCH = 14 (hypochromic)
- Serum ferritin = low
- Serum iron = low
- IBC (iron binding capacity) = high
- Saturation = low
This indicates low iron stores
Is iron deficiency a diagnosis?
No. We must identify the cause of the deficiency
Anaemia occurs late in iron deficiency
_______ occurs late in _____ deficiency
Anaemia occurs late in iron deficiency
What are the causes of iron deficiency?
1) Diet
- e.g. vegetarian
2) Malabsorption
- proximal small bowel (jejunum)
3) Increased demands
- e.g. pregnancy and breastfeeding
4) Chronic blood loss
- GI or Gu tract
- Doesn’t necessarily present with melena (dark black, tarry feces that are associated with upper gastrointestinal bleeding.)
What are the common causes of iron deficiency in…
1) Children
2) Pre-menopausal females
3) Males and post menopausal females?
Children- Deficient dietary intake
Pre-menopausal females- imblanace between diet intake and menstrual loss
Males and post menopausal female - occult blood loss