Anaemia Flashcards
Define anaemia
- reduced total red cell mass
What markers can be used in anaemia?
- haemoglobin concentration
- haematocrit
Normal haemoglobin and hamatocrit concentrations in males and females
- males (>130, Hct> 0.38)
- females (>120, hct>0.37)
How is haemoglobin concentration measured in the lab?
- burst red cell
- stabilise Hb with cyan-metHb
- measure optical density
What law describes the OD proportion to the concentration
- Beer’s law
When might haemoglobin concentration not be accurate?
- immediately after trauma event with blood loss
- haemodilution with fluids
What triggers reticulocytosis?
- hypoxia
- sensed by the kidneys
- erythropoietin released
Explain reticulocytes?
- just left bone marrow
- young and larger
- stain purple/deep red
What levels can be measured from a blood sample
- haemoglobin concentrations
- number of red cells
- size of red cells (MCV)
What levels can be calculated from blood samples?
- haematocrit
- mean cell haemoglobin
- mean cell haemoglobin concentration
2 main pathophysiologies of anaemia?
- decreased production (hypo-proliferation, maturation abnormality)
- increased loss or destruction (bleeding, haemolysis)
Where is Hb synthesised?
- in the cytoplasm
Explain microcytic anaemia?
- low mcv, low red cell numbers
- small and hypochromic
- deficient haemoglobin synthesis
Causes of microcytic anaemia?
- TAILS
- Thalassaemia (globin deficiency)
- Anaemia of chronic disease
- Iron deficiency
- Lead posing
- Sideroblastic anaemias
Where is iron absorbed
- proximal duodenum
How is iron transported?
- transferrin
How is iron stored
- ferritin
Explain transferrin
- 2 binders for iron
- transfers from tissue to cells
- % saturation measured
When might percentage saturation of transferrin be reduced?
- iron deficiency
- chronic disease
When might transferrin saturation be increased?
- genetic haemachromatosis
What is ferritin?
- storage form of iron
- may be high in infection or inflammation
Blood results in iron deficiency
- low serum iron
- low hb
- low ferritin
- low MCV
Iron deficiency may cause what type of anaemia?
- microcytic anaemia
Epithelial changes in iron deficiency?
- dry skin
- koilonychia
- angular chelitis
causes of iron deficiency
- reduced dietary
- losing iron
- malabsorption
How can iron loss be estimated during blood loss?
- volume of blood loss/ 2 = iron loss
Treatment of iron deficiency?
- treat underlying cause
- iron supplements
Complication of oral iron supplementation
- gut irritant
- dark stools and constipation
- may lead to poor compliance
Describe macrocytosis
- big increase in red cell size
Define macrocytic anaemia
- reduction in red blood cells
- increase in volume
Normal MCV values
- microcytic < 80
- normocytic 80-100fl
- macrocytic > 100fl
How is MCV measured?
- light scatter beam
True macrocytosis may be ___ or ___
- megaloblastic
- non-megaloblastic
Explain normoblast development
- pronomoblast
- early normoblast
- intermediate normoblast
- late normoblast
- reticulocyte
- erythrocyte
Describe megaloblast
- abnormally large
- immature nucleus
- reside in bone marrow
Descrive megaloblastic anaemia?
- lack or RBC
- Larger MCV
- megaloblasts in bone marrow
- reduced cell division
- increased apoptosis
- bone marrow hypercellular
Causes of megaloblastic anaemia?
- B12 deficiency
- folate deficiency
- anti-convulasants
Role of B12 and folate
- co factors
- nuclear maturity
- reduced = impairment to nervous system
Where is vit B12 found
- meat and egg
What binds to B12 for absorption
- intrinsic factor
What secretes intrinsic factor
- parietal cells
Where is vit b12 absorbed
- ileum
Causes of a vit b12 deficiency
- dietary
- pernicious anaemia
What is pernicious anaemia
- autoimmune destruction of gastric parietal cells
- ass. with other autoimmune conditions
- less intrinsic factor = vit b 12 deficiency
- vit b12 IM
What is the body storage timeline of vit b12?
- 2-4yrs
Where is folate found?
- plant substances
Where is folate absorbed?
- proximal small bowel
Causes of a folate deficiency?
- dietary
- coeliac or chrons
- haemolysis
- pregnancy
- malignancy
Folate deficiency may cause what type of anaemia?
- macrocytic anaemia
Typical storage timeline of folate in the body
- 3 months
Symptoms of a vit b12 deficeincy
- anaemic
- weight loss
- diarrhoea
- pre hepatic jaundice
- neurological symptoms
In macrocytic anaemia blood film what else may be visible
- macrovalocytes
- hyper-segmented neutrophils
Anti-gastric parietal antibody
- sensitive
- not specific
- pernicious anaemia
Anti-intrinsic factor
- specific
- not sensitive
- pernicious anaemia
Treatment of a folate deficiency
- folic acid
Non-megaloblastic macrocytosis causes?
- liver disease
- alcohol
- hypothyroidism
- marrow failure
Why might spurious macrocytosis occur?
- wrongly picked up as macrocytic anaemia
- reticulocytosis
- cold-agglutinin
Iron + porphyrin =
- haem
How might you biochemically distinguish between continued blood loss and poor compliance of iron tablets?
- reticulocyte count
Define haemolysis
- premature red cell destruction
Why are red cells specifically susceptible to damage?
- biconcave structure
- no mitochondria = limited metabolic reserve
- no nucleus = cannot generate new proteins
Describe compensated haemolysis?
- increased red cell production to even out destruction
- normal Hb
Define decompensated haemolysis?
- destruction > production
- low Hb
What are the consequences of haemolysis?
- erythroid hyperplasia
- excess red cell breakdown products
What stains reticulocytes blue and why?
- new methylene blue stain
- due to the presence of RNA
What are the consequences to the bone marrow of haemolysis?
- reticulocytosis
- erythroid hyperplasia
Explain extravascular haemolysis?
- taken up by the spleen and liver
- commoner
- hyperplasia at site of destruction
Blood results in extravascular haemolysis?
- protoporphyrin
- urobilinogenuria
Describe intravascular haemolysis?
- RBC destroyed within circulation
Causes of extravascular haemolysis
- haemolytic disease of the newborn
- delayed transfusion reaction
- hereditary spehrocytosis
- sickle cell
- thalasseamia
Intravascular haemolysis causes?
- ABO incompatible blood (acute)
- G6PD deficiency
- malaria
Blood results in intravascular haemolysis?
- haemoglobuminaemia
- methaemalbuminaemia
- haemosiderinuria
Investigations into haemolysis?
- FBC
- Reticulocyte count
- serum unconjugated bilirubin
- serum haemoglobin
- urinary urobilinogen
What is warm haemolysis mediated by?
- IgG
What is cold haemolysis mediated by?
- IgM
Causes of warm haemolysis
- idiopathic
- autoimmune (SLE)
- Drugs (penicillins)
- infection
Causes of cold haemolysis?
- idiopathic
- infection (EBV)
What is Direct Coombs test?
- identifies antibody bound to own red cell
Immediate vs delayed autoimmune transfusion reaction?
- immediate (IgM)
- delayed (IgG)
Examples of alloimmune haemolysis?
- haemolytic transfusion reaction
- haemolytic disease of the newborn
What mechanical reasons may cause haemolytic anaemia?
- mechanical valve
- burns related
Blood film in a severe burns patient?
- microspherocyte
Describe hereditary spherocytosis?
- defects in the proteins that aid red cell membrane flexibility
- splenomegaly and gallstones
- autosomal dominatn
Effect of a G6PD disease
- more suceptible to oxidative damage
- problems with ATP generation
