ANAEMIA AND HAEMATINIC DEFICIENCIES Flashcards
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What is haematocrit?
the ratio of the volume of red blood cells to the total volume of blood.
What are the three classifications of anaemia?What objective measure is used to distinguish between them?What are some examples of causes of each?
Microcytic (MCV <80 fL)
- Thalassaemia and thalassaemia trait
- iron deficiency
- anaemia of chronic disease
- sideroblastic anaemi
Normocytic (MCV 80-95 fL)
- Anaemia of chronic disease
- acute blood loss
- mixed haematinic deficiencies
- bone marrow failure (aplastic anaemia, chemotherapy)
Macrocytic (MCV >95 fL)
- Megaloblastic anaemia
- Myelodysplasia
- Haemolytic anaemia
- Liver disease
- Alcohol
- Hydroxycarbamide
- Pregnancy
- Hypothyroidism
What are the 3 main categories of congenital anaemia? Give 2 examples for each.
Membrane defect
- Hereditary spherocytosis
- Hereditary elliptocytosis
Haemoglobin defect
- Sickle cell anaemia
- Thalassaemia
Enzyme defect
- G6PD deficiency
- Pyruvate kinase deficiency
What changes in the blood are seen during and after an acute bleed?
Initially there is no change in haemoglobin concentration as everything is being lost in equal measure.However the immediate compensatory mechanism is to produce plasma resulting in a subsequent drop in haemoglobin concentration.As the body attempts to make the red cells back up, it can become iron deficient. This results in a microcytic hypochromic anaemia on blood film
What are the symptoms and signs of iron deficiency?
Symptoms of anaemiaBreathlessnessPalpitationsFatigueTinnitusSigns of anaemiaPallorTachycardiaFlow murmur/hyperdynamic circulationPica
List some causes of iron deficiency?
Dietary
- Poor absorption: coeliac disease, Crohn’s disease
- Increased requirement: pregnancy
- Iron loss: GI bleed, menorrhagia, urinary
Diagnosis of iron deficiency.Iron deficiency anaemia and anaemia of chronic disease present differently on iron studies.
Ferritin
Serum Iron
Transferrin saturation
TIBC/transferrin
Iron deficiency
Ferritin- LOW
Serum Iron- LOW
Transferrin saturation- LOW
TIBC/transferrin- HIGH
Anaemia of chronic infection
Ferritin- NORMAL (can be falsely elevated in inflammation)
Serum Iron- LOW
Transferrin saturation- LOW
TIBC/transferrin- LOW
What role do vitamin b12 and folate have in DNA production?
Dietary folate is converted into methyl-tetrahydrofolate after being absorbed through the small intestine. Methyl-THF is converted into THF through conversion of homocysteine to methionine with vitamin b12.
Causes of folate deficiency?
Low intakeImpaired absorption
- Coeliac/Crohn’s
- Drugs
Increased requirement
- Haemolysis
- Pregnancy
- Prematurity
- Inflammation
- Homocystinuria
Increased excretion loss
- Dialysis
- Drugs
Signs and symptoms specific to folate and b12 deficiency?
Unconjugated hyperbilirubinaemiaGlossitisAngular cheilosisMild feverSkin hyperpigmentationInfection and bleeding if neutropoenic
What is a megaloblast?
Immature red blood cells with oversized nuclei
Which of folate or b12 has the longer storage time in the body?
B12 (3-4 years vs 3-4 months)
What are the signs and symptoms of b12 deficiency?
SymptomsParasthesiaeMuscle weaknessDifficulty walkingConfusion, slownessSignsPeripheral neuropathyLong tract demyelinationDementia
Why are LDH and haptoglobin suitable tests in assessing haemolytic anaemia?
Lactate dehydrogenase is released from ruptured red blood cellsHaptoglobin binds free haemoglobin in the serum and so is depleted in haemolytic anaemia.
