Haematology: Anaemia Flashcards
Does the normal Hb range vary with age?
Yes
Anaemia in neonates = <140
1 month to 12 months <100
1 year to 12 years <110
What mechanisms does anaemia result from?
Reduced red cell production - ineffective erythropoiesis (iron deficiency is most common) or due to red cell aplasia
Increased red cell destruction (haemolysis)
Blood loss - uncommon in children
If there is a combination of the 3 mechanisms of anaemia, what is it called?
Anaemia of prematurity
What causes of impaired red cell production are there?
Red cell aplasia:
Parvovirus B19 infection
Congenital - Diamond-Blackfan anaemia
Transient erythroblastopenia of childhood
Rarities- Fanconi anaemia, aplastic anaemia, leukaemia
Ineffective erythropoiesis: Iron deficiency Folic acid deficiency Chronic inflammation e.g juvenile idiopathic arthritis Chronic renal failure Rarities - mylodysplasia, lead poisoning
What causes of haemolysis are there?
Red cell membrane disorders - hereditary spherocytosis
Red cell enzyme disorders - G6PD
Haemoglobinopathies - thalassaemias, sickle cell disease
Immune - HDN, autoimmune haemolytic anaemia
Blood loss can cause anaemia, what can lead to this?
Chronic GI blood loss e.g Meckel diverticulum
Inherited bleeding disorders - Von Willebrand disease
What does red cell aplasia mean?
Complete absence of red cell production
What does ineffective erythropoiesis mean?
Red cell production occurs at normal or increased rate, but differentiation and survival of the red cells is defective
What diagnostic clues to ineffective erythropoiesis are there?
Normal reticulocyte count
Abnormal MCV - low in iron deficiency, high in folic acid deficiency
What are reticulocytes?
Immature RBCs
Appear slightly larger and have a mesh like pattern of RNA that is visible under certain stains
Circulate in blood from approx 1 day before developing into mature RBCs
What are the main causes of iron deficiency?
Inadequate intake
Malabsorption
Blood loss
Is inadequate intake of iron common in infants?
Yes because additional iron is required for the increase in blood volume accompanying growth and to build up the child’s stores
Where can iron come from?
Breastmilk - low iron content, but 50% absorbed
Infant formula - supplemented with iron
Cow’s milk - higher iron content than breastmilk but only 10% absorbed
Solids introduced at weaning e.g cereals
Iron deficiency may develop due to delay in mixed feeding introduction or diet with insufficient iron rich foods, especially if large amount of cow’s milk
What vitamin increased iron absorption?
Food rich in vitamin C
What inhibits iron absorption?
Tannin in tea
Why should infants not be fed up modified cow’s milk?
It’s iron content is low and poorly absorbed
Most children are asymptomatic until the Hb drops below…
60-70g/L
What symptoms are associated with anaemia?
Tire easily
Young infants feed more slowly
May appear pale
Ask about blood loss and symptoms/signs suggesting malabsorption
Pica - inappropriate eating of non food materials e.g soil, chalk
Might impact behaviour and intellectual function
What blood results suggest iron deficiency anaemia?
Hypochromic - low Hb content Microcytic - small RBCs Low serum ferritin Low serum iron Increased total iron binding capacity
What are the main cause of microcytic anaemia?
Thalassaemia (beta) Anaemia of chronic disease - e.g due to chronic kidney disease Iron deficiency anaemia Lead poisoning Sidroblastic
How is iron deficiency anaemia managed?
Dietary advice
Supplementation with oral iron - Sytron or Niferex
How long should iron supplementation be taken for?
Continue until Hb normal then minimum of 3 further months to replenish stores
If child does not respond to oral iron, what does this suggest?
Non compliance with treatment
Investigate for other causes especially malabsorption- coeliac disease or chronic blood loss
Should a blood transfusion be necessary for dietary iron deficiency anaemia?
No
Even children with deficiency of 20-30g/L due to iron deficiency have arrived at this level over a prolonged period and can tolerate it
Some children have low serum ferritin, but have not yet developed anaemia. Should they be treated with oral iron?
Controversial
- iron required for normal brain development
- treatment carries risk of accidental poisoning
Simple strategy: provide dietary advice and offer parents the decision to add oral iron supplementation
What should you suspect in recurrent IDA?
Bleeding - Meckel’s diverticulum or oesophagitis
