Haematology Flashcards
Changes to haemoglobin synthesis in newborn
Decreasing production of Fetal Hb (2 alpha, 2 gamma)
Increasing production of adult Hb (HbA and HbA2)
Changes to haemoglobin concentration at birth
High at birth, falls to lowest level at 2 months
Anaemic values according to age group
Neonate: <140g/L
1month - 12 months: <100g/L
1 year - 12 years: <110g/L
Causes of anaemia in children
- Impaired red cell production
- red cell aphasia (absence of production)
- ineffective erythropoiesis: iron deficiency - Increased red cell destruction
- hereditary spherocytosis (membrane)
- Thalassaemias (haemoglobinopathies)
- G6PDH deficiency (enzyme)
- autoimmune haemolytic anaemia - Blood loss
- coagulopathies
- GI (meckel diverticulum)
Diagnostic approach to anaemia in children
A. Reticulocyte low:
- red cell aplasia
- causes: Parovirus B19, congenital
- tests: Parovirus serology, bone marrow aspirate
B. Reticulocyte normal/high:
- bilirubin raised
- causes: hereditary spherocytosis, sickle cell, thalassaemia
- tests: blood film, Hb electrophoresis
- bilirubin normal
- causes: blood loss, iron deficiency anaemia
- tests: blood film, serum ferritin
Causes of iron deficiency anaemia in children
Inadequate intake:
Delay in introduction to mixed feeding beyond 6 months
Diet excess in cows milk
Blood loss
Malabsorption
Why is iron requirement high in children
Increase in blood volume accompanying growth
Need to build up iron stores
Content and absorption of iron from milk and solid food
Breast milk - low content but 50% absorbed
Infant formula - high iron content
Cows milk - low iron content and 10% absorbed
Mixed diet - high content
Sources of iron in diet
Red meat, oily fish
Pulses, fortified breakfast cereals, dark green veg, dried fruit, nuts
Vitamin c increases iron absorption
Tea and Fibre decreases iron absorption
Clinical features of iron deficiency anaemia
Asymptomatic until <60g/L
Feed slowly
Tire easily
‘Pica’ - inappropriate eating of non-food materials
Behavioural and intellectual deficiencies
Investigations for iron deficiency anaemia
FBC - Low Hb, Low MCV and MCH, microcytic hypochromic red cells
Serum ferritin - Low
Differentials for iron deficiency anaemia
Beta thalassaemia trait
Anaemia of chronic disease
Management of iron deficiency anaemia
Dietary advice
Iron Supplement - Styron, niferex
Duration of iron supplement treatment
Until Hb normal then minimum of further 3 months
Treatment if iron deficiency with normal Hb
Dietary advice and offer option of iron supplements
- risk of iron toxicity w treatment
- risk of behaviour and intellectual function with iron deficiency
Define thrombocytopenia
Platelet count <150x10^9/L
Severity of thrombocytopenia and their risk of bleeding
Severe: <20, risk of spontaneous bleeding
Moderate: 20-50, risk of severe bleeding during operation/trauma
Mild: 50-150, low risk of bleeding unless major operation/trauma
Clinical features of thrombocytopenia
Petechiae Purpura Bruising Mucosal bleeding - epistaxis, gum Severe bleeding - GI, intracranial
Differentials for purpura/bruising
A. Thrombocytopenia
- increased destruction
- Immune: ITP, SLE
- Non-Immune: DIC, CHD, Hypersplenism, TTP - decreased production
- aplastic anaemia
- leukaemia, marrow infiltration
B. Platelet dysfunction
- uraemia
C. Vascular disorders
- congenital: Ehlers Danlos, Marfans
- meningococcal infections
- vasculitis
Define immune thrombocytopenia
Autoimmune destruction of platelets by antiplatelet IgG autoantibodies
Prevalence of ITP
Most common cause of thrombocytopenia in children
Clinical features of ITP
2-10 years
Onset 1week after viral infection
Features of thrombocytopenia
Investigations for ITP
Diagnosis of exclusion - isolated thrombocytopenia in absence of other causes
FBC
Blood film
Bone marrow - to exclude lEukaemia, aplastic anaemia; If starting steroids to rule out ALL
Management of acute ITP
Self-limiting: resolves in 6 weeks
Supportive: 24hr access to hospital, avoid contact sports
Medical: if major / persistent bleeding
Oral prednisolone
IV anti-D
IV Immunoglobulin
Platelet transfusion - ONLY if life threatening haemorrhage
