Anaemia

  • Assessment

    Definition

    Anaemia is defined as Hb less than the lower limit of the reference range for age:

    Age Lower limit of normal range of Hb (g/l)
    2 months 90
    2 - 6 months 95
    6 - 24 months 105
    2 - 11 years 115
    > 12 years girls - 120 boys - 130

    Symptoms / signs suggestive of Anaemia

    • Pallor
    • Pale conjunctivae
    • Flow murmur
    • Lethargy
    • Poor growth
    • Signs of cardiac failure
    • Weakness
    • Listlessness
    • Shortness of breath

    Investigation

    If anaemia is suspected begin with a full blood examination, blood film and reticulocyte count.

    Any further investigations will be determined by the blood film appearance.

    The initial classification is based on the MCV:

    Anaemia flowchart

    Management

    Consider admission if:

    • Possible malignancy or infiltrative disorder
    • Hb < 60g/l  (including iron deficiency)
    • Haemolysis
    • Needs transfusion (Where possible defer transfusion until a definitive diagnosis is made)

    Iron deficiency

    • If dietary history is strongly suggestive of iron-deficiency, modify diet + give iron supplementation (if Hb < 100g/l, or low ferritin even if Hb normal). Arrange follow-up to ensure appropriate response to treatment.
    • Dietary advice (increase red meat, chicken, fish, pulses, green vegetables; limit cow's milk consumption to 500 ml/day)
    • Iron supplementation - see here
    • Transfusion rarely required (eg. cardiac failure, urgent surgery required)

    Haemolytic anaemia

    Usually requires admission and repeat FBE within 6-12 hours to detect continuing haemolysis. Acute haemolysis in childhood can be a life threatening illness.

    Investigations: blood film for RBC abnormalities (eg. spherocytosis), Coomb's test, G6PD screen, bilirubin, reticulocytes.

    Notes

    MICROCYTIC ANAEMIA

    Iron deficiency

    • Commonest cause of anaemia in children
    • Usually nutritional (insufficient red meat, fish, chicken, green vegetables, pulses; excessive cow's milk); rarely due to malabsorption or GI bleeding
    • Risk factors include prematurity, low birth-weight, multiple pregnancy, exclusive breast-feeding after 6 months and excessive cow's milk. Aboriginals and adolescent females are also at risk.
    • Can lead to reduced cognitive and psychomotor performance in the absence of anaemia.

    ￟ Thalassaemia minor

    • microcytosis with normal or bordeline low Hb
    • diagnosed on Hb electrophoresis - HbA2 > 3.5%
    • South East Asian, Mediterranean, Arabic families
    • usually asymptomatic; often positive family history
    • pre-pregnancy carrier testing of partner important

    Note: HbA2 may not be elevated in the presence of concomitant iron deficiency, therefore give iron therapy (if ferritin low) before ordering test.

    Alpha Thalassaemia

    • microcytosis with normal or bordeline low Hb
    • South East Asian, African Arabic families
    • cannot be easily diagnosed on Hb electrophoresis - dna testing usually required (not a first-line investigation - exclude other causes first)

    Rare causes of Microcytic Anaemia

    • Chronic inflammation
    • Chronic lead poisoning (high blood lead level)
    • Sideroblastic anaemia

    Hypoplastic/Aplastic Anaemia

    (eg. acute leukaemia, aplastic anaemia, infiltrative disorders)

    • Consider if white cells and/or platelets also depressed
    • May be due to drugs eg. cytotoxics, chloramphenicol, sulfonamides
    • If isolated anaemia, consider transient erythroblastopenia of childhood (response to viral infection) or congenital forms (eg. Diamond-Blackfan syndrome)
    • Bone marrow aspirate is usually required for diagnosis

    MACROCYTIC ANAEMIA

    Rare in children; discuss with registrar or consultant.

    If associated with Failure to thrive or neurodevelopmental problems then must be investigated and treated urgently.