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Medicine Notes Paediatrics Notes

Haematology And Oncology Notes

Updated Haematology And Oncology Notes

Paediatrics Notes

Paediatrics

Approximately 336 pages

Paediatric notes based upon current NICE guidance, The Illustrated Textbook of Paediatrics by Lissauer and Clayden in conjunction with the Oxford Handbook of Paediatrics...

The following is a more accessible plain text extract of the PDF sample above, taken from our Paediatrics Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:

Haematology and Oncology

Types of Hb

  • Embryonic Hb Gower 1, Hb Gower 2, Hb Portland

  • Fetal HbF (holds onto oxygen better than HbA oxygen dissociation curve shifts to the right at birth [offloads oxygen more readily])

  • Adult HbA (97%), HbA2

Anaemia

  • Hb below the normal range

    • Neonate <14g/dl

    • 1-12 months <10g/dl

    • 1-12 years <11g/dl

  • Anaemia may be due to:

    • Reduced RBC production

      • Red cell aplasia

      • Ineffective erythropoiesis

        • Fe deficiency

        • Folid acid deficiency

    • Haemolysis

      • Red cell membrane disorders hereditary spherocytosis

      • Red cell enzyme disorders glucose6 phosphate dehydrogenase deficiency

      • Haemoglobinopathies thalassaemias, sickle cell

      • Immune haemolytic disease of the newborn, autoimmune

    • Blood loss

Anaemia Due To Reduced Red Cell Production

  • Ineffective erythropoiesis differentiation and survival of RBCs is defective

    • Reticuloctye count will be normal

    • MCV will be abnormal

      • Low in iron deficiency

      • High in folate deficiency

  • Complete absence of RBC production in red cell aplasia

    • Low or absent reticulocyte count

    • Causes

      • Congenital – Diamond-Blackfan anaemia

      • Transient erythroblastopenia of childhood

      • Parvovirus B19 (only in those with inherited haemolytic anaemias)

Iron Deficiency

  • Term newborn iron stores of 250mg

  • Adult iron stores of 4-5g

  • Causes

    • Inadequate intake common in infantc

      • 1 year old requires 8mg/day

    • Malabsorption

    • Blood loss

  • Iron sources

    • Breast milk – low content but 50% of iron is absorbed

    • Infant formula

    • Cow’s milk – higher content than breast but only 10% absorbed

    • Solids introduced at weaning

  • Increase absorption with Vitamin C

  • Clinically

    • Asymptomatic until Hb drops below 7g/dl

    • Tire easily

    • Feed slowly

    • Pallor (esp. conjunctivae, tongue or palmar creases)

    • Pica

  • Diagnosis

    • Microcytic, hypochromic anaemia (low MCV and MCH)

      • ; B/a-thallassaemia, anaemia of chronic disease

    • Low serum ferritin

  • Management

    • Dietary advice

    • Oral supplementation

      • Continue until Hb is normal and for a further 3 months

    • Blood transfusion should NEVER be necessary for dietary iron deficiency

Increased Red Cell Destruction

  • Increased destruction either in the circulation (intravascular) or in the liver/spleen (extravascular)

  • Haemolysis only leads to anaemia when the bone marrow can no longer compensate

  • Main cause in children is intrinsic abnormalities of the RBC

    • Red cell mebrane disorders (hereditary spherocytosis)

    • Red cell enzyme disorders (G6PD deficiency)

    • Haemoglobinopathies (thalassaemia, sickle cell)

  • Haemolysis leads to:

    • Anaemia

    • Hepatomegaly

    • Splenomegaly

    • Increased blood levels of unconjugated bilirubin

    • Excess urinary urobilinogen

  • Diagnosis

    • Raised reticulocyte count (polychromasia)

    • Unconjugated bilirubinaemia and increased urinary urobilinogen

    • Abnormal appearance of red cells on blood film

    • Positive direct antiglobulin test (Coomb’s) [only in immune cause]

    • Increased red cell precursors in the bone

Hereditary Spherocytosis

  • 1 in 5000 caucasian births

  • Autosomal dominant

  • Mutations in genes coding for red cell membrane proteins spectrin, ankyrin or band 3

  • Reduction in surface to volume ratio spheroidal destruction in the spleen

  • Clincally

    • Suspected due to family history

    • Jaundice intermittent during childhood OR severe jaundice in the first few days of life

    • Anaemia mild (9-11g/dl)

    • Mild/moderate splenomegaly

    • Aplastic crisis transient due to parvovirus B19

    • Gallstones due to increased bilirubin

  • Diagnosis

    • Blood film

    • - Autoimmune haemolytic anaemia

      • Excluded with a direct antibody test in the absence of a family history of hereditary spherocytosis

  • Management

    • Oral folic acid

    • Splenectomy is indicated for poor growth or troubelsome symptoms of anaemia

      • Defer until 7 years old

      • Vaccinated against Hib, Meningitis C and strep. Pneumoniae beforehand

      • Lifelong daily oral penicillin prophylaxis

    • Aplastic crisis

      • 1 or 2 blood tranfusions over 3-4 weeks when no RBCs are produced

Glucose-6 Phosphate Dehydrogenase Deficiency

  • High prevalence in those originating from central Africa, the Mediterranean, the Middle East and the Far East

  • Rate limiting enzyme in the pentose phosphate pathway and prevents oxidative damage to RBCs

  • X linked and therefore largely affects males

  • Clinically

    • Neonatal jaundice

    • Acute haemolysis precipitated by:

      • Infection

      • Drugs antimalarials, sulphonamides, quinolones, nitrofuratoin

      • Fava bean

    • Intravascular haemolysis fever, malaise

    • Dark urine – urobilinogen and Hb

  • Diagnosis

    • Measure G6PD activity in RBCs

    • During a crisis the G6PD levels may be mistakingly elevated due to higher enzyme concentration in reticulocytes

  • Management

    • Info regarding signs of acute haemolysis (jaundice, dark urine)

    • And list of druge, chemicals and food to avoid

Haemoglobinopathies

  • Reduced or absent production of HbA (thalasaemia) or production of abnormal Hb (sickle cell)

Sickle Cell

  • 1 in 2000 live births

  • Most common in patients who have black parents and originate from tropical Africa or the Caribbean

  • Mutation in codon 6 of the B globin chain HbS forms

  • Clincal manifestation is delayed until 6 months when the HbF has all but disappeared

  • Three main forms of disease and the sickle cell trait

    • Sickle Cell Anaemia (HbSS)

      • Homzygous for HbS

    • HbSC Disease

      • HbS from one parent and HbC from the other

        • HbC forms due to a different point mutation in B globin

      • No HbA – as no normal B globin genes

      • Develop proliferative retinopathy

      • Osteonecrosis of hips and shoulders

    • Sickle B thalassaemia

      • HbS from one parent and B thalassaemia trait from the other

      • No normal B globin genes

    • Sickle Trait

      • HbS from one parent and a normal B globin chain from the other

      • 40% of Hb is HbS

      • Carriers

      • Asymptomatic

  • Clinical Features

    • Anaemia moderate anaemia with detectable jaundice

    • Infection

      • Esp. from encapsulated organisms (pneumococci, Hib)

      • Osteomyelitis due to Salmonella

      • Due to hyposplenism secondary to microinfarction in the spleen

    • Painful Crises

      • Vaso-occlusive crisis

      • Dactylitis with pain and swelling in the hands and feet in late infancy

      • ...

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