Flashcards in Haematological Disorders Deck (139)
When is HbF very low in healthy children - when is it not?
By age 1
Increased proportions of HbF are indicators of severe inherited disorders of haemoglobin production - haemoglobinopathies
Hb at birth
14-21.5g/dl to compensate for low oxygen concentration in fetus
What happens to Hb after birth
Falls over first few weeks of life, mainly due to reduced red cell production, to 10g/dl at 2 months of age
What happens to Hb after birth in pre-term babies?
It has a steaper fall to a mean of 6.5-9g/dl at 4-8 weeks chronological age
What are the iron, B12 and folic acid stores like in term and preterm infants at birth and after birth?
Iron, B12 and folic acid are adequate at birth in term and preterm babies
However in preterm babies stores of iron and folic acid are lower and are depleted more quickly leading to deficiency after 2-4months if recommended daily intakes are not maintained by supplements
Anaemia value in neonate
Hb less than 14g/dl
Anaemia value in 1-12months old
Hb less than 10g/dl
Anaemia value in 1-12 years
Hb less than 11g/dl
What is red cell aplasia
Complete absence of red cell production
What is ineffective erythropoeisis?
Red cell production is normal/increased rate but differentiation or survival of red cells is defective
What are the main causes of iron deficiency anaemia x3
Inadequate intake (common in infants)
Which milk is not good for maintaining infant iron levels?
Cows milk because it has a higher iron content than breast milk but only 10% of the iron is absorbed
Therefore infants should not be fed unmodified cows milk
At what Hb level do children become symptomatic with anaemia?
How do children with iron deficiency anaemia present?
Pica- eating non-food materials such as soil, chalk, gravel or foam rubber
What are indicators on blood tests of iron deficiency anaemia
Microcytic, hypochromic anaemia (low MCV and MCH)
Low serum ferritin
Management of iron deficiency anaemia in infants?
Increase oral iron intake with supplementation - Sytron or Niferex are best tolerated preparations
Or just increase iron rich foods
What are the 3 main causes of red cell aplasia in children?
1) Diamond-Blackfan anaemia - congenital red cell aplasia
2) Transient erythroblastopenia of childhood
3) Parvovirus B19 infection in children with haemolytic anaemia
Diagnostic features of red cell aplasia x4
Low reticulocyte count despite normal Hb
Negative direct antiglobulin/Coombs test
Absent red cell precursors on bone marrow examination
What is Diamond-Blackfan anaemia?
It is a rare congenital disease of red cell aplasia
Inheritance of Diamond-Blackfan anaemia
20% family history - remaining 80% are sporadic mutations
RPS (ribosomal protein) genes implicated in some cases
Presentation of Diamond-Blackfan anaemia
Most present at 2-3 months of age but 25% present at birth
Features of Diamond-Blackfan anaemia x2
Also congenital abnormalities such as short stature or abnormal thumbs
Treatment of Diamond-Blackfan anaemia x2
Monthly red cell transfusions for children not responsive to steroids
What is transient erythoblastopenia of childhood?
Red cell aplasia usually triggered by viral infections
Same haemotological features as D-Blackfan anaemia
Prognosis of transient erythroblastopenia of childhood
Always recovers - usually within several weeks (hence differs from d-blackfan)
Inheritance of transient erythroblastopenia of childhood
No family history
When does haemolysis lead to anaemia?
When the bone marrow can no longer increase red cell production to compensate for the premature destruction of red cells
Main causes of haemolytic anaemias in children? What is uncommon children
Intrinsic abnormalities of RBCs (membrane and enzyme disorders and haemoglobinopathies)
Immune haemolysis is uncommon
What does haemolysis from increased RBC breakdown lead to? x4
Hepatomegaly and splenomegaly
Increased blood levels of unconjugated bilirubin
Increased urinary urobilinogen