Anaemia

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    Anaemia is defined as a haemoglobin (Hb) level below reference values, which vary depending on sex, age and pregnancy status (see Table 2).

     

    Anaemia may be caused by:

    • Decreased production of red blood cells: iron deficiency, nutritional deficiencies (folic acid, vitamin B12, vitamin A), depressed bone marrow function, certain infections (HIV, visceral leishmaniasis), renal failure;
    • Loss of red blood cells: acute or chronic haemorrhage (ancylostomiasis, schistosomiasis, etc.);
    • Increased destruction of red blood cells (haemolysis): parasitic (malaria), bacterial and viral (HIV) infections; haemoglobinopathies (sickle cell disease, thalassaemia); intolerance to certain drugs (primaquine, dapsone, co-trimoxazole, etc.) in patients with G6PD deficiency.

     

    In tropical settings, the causes of anaemia are often interlinked.

    Clinical features

    • Common signs: pallor of the conjunctivae, mucous membranes, palms of hands and soles of feet; fatigue, dizziness, dyspnoea, tachycardia, heart murmur.
    • Signs that anaemia may be immediately life threatening: sweating, thirst, cold extremities, oedema in the lower limbs, respiratory distress, angina, shock.
    • Significant signs: cheilosis and glossitis (nutritional deficiency), jaundice, hepatosplenomegaly, dark coloured urine (haemolysis), bleeding (maelena, haematuria, etc.), signs of malaria.

    Laboratory

    • Hb levels
    • Rapid test or systematic thick and thin blood films in areas where malaria is endemic.
    • Urinary dipstick: check for haemoglobinuria or haematuria.
    • Emmel test if sickle cell disease is suspected.
    • Blood cell count if available to guide diagnosis.

     

    Table 1 - Possible diagnoses with blood cell count

     

    Characteristics

    Possible diagnoses

    Macrocytic 

    Deficiency (folic acid, vitamin B12), chronic alcoholism

    Microcytic

    Iron deficiency (malnutrition, chronic haemorrhage), chronic inflammation (HIV infection, cancer), thalassaemia

    Normocytic 

    Acute haemorrhage, renal failure, haemolysis

    Reduced number of reticulocytes

    Deficiency (iron, folic acid, vitamin B12), spinal tumour, renal failure

    Increased or normal number of reticulocytes

    Haemolysis, sickle cell disease, thalassaemia

    Eosinophilia

    Ancylostomiasis, trichuriasis, schistosomiasis, HIV infection, malignant haemopathies

     

    Aetiological treatment

    Anaemia in itself is not an indication for transfusion. Most anaemias are well tolerated and can be corrected with simple aetiological treatment.
    Aetiological treatment may be given alone or together with transfusion.

    • Iron deficiency
      ferrous salts PO for 3 months. Doses are expressed in elemental iron a Citation a. Available in 140 mg/5 ml syrup of ferrous fumarate containing approximately 45 mg/5 ml of elemental iron and 200 mg ferrous sulfate tablets or ferrous sulfate + folic acid tablets containing 65 mg of elemental iron. Tablets of 185 or 200 mg ferrous fumurate or sulfate + folic acid (60 or 65 mg of elemental iron) contain 400 micrograms folic acid. :
      Neonates: 1 to 2 mg/kg 2 times daily
      Children 1 month to < 6 years: 1.5 to 3 mg/kg 2 times daily
      Children 6 to < 12 years: 65 mg 2 times daily
      Children ≥ 12 years and adults: 65 mg 2 to 3 times daily

     

    Age

    Weight

    Treatment
    45 mg/5 ml syrup 65 mg tablet
    < 1 month < 4 kg 0.5 ml x 2
    1 month to < 1 year 4 to < 10 kg 1.5 ml x 2
    1 to < 6 years 10 to < 20 kg 2.5 ml x 2
    6 to < 12 years 20 to < 40 kg 1 tab x 2

     

    or preferably,
    ferrous saltsfolic acid  PO based on elemental iron dosages.

    • Helminthic infections: see Schistosomiasis and Nematode infections (Chapter 6).
    • Folic acid deficiency (rarely isolated)
      folic acid PO for 4 months
      Children < 1 year: 0.5 mg/kg once daily
      Children ≥ 1 year and adults: 5 mg once daily
    • Malaria: see Malaria (Chapter 6). In the event of associated iron deficiency, wait 4 weeks after malaria treatment before prescribing iron supplements.
    • Suspected haemolytic anaemia: stop any drug that causes haemolysis in patients with (or that may possibly have) G6PD deficiency.

    Blood transfusion

    Indications

    To decide whether to transfuse, several parameters should be taken into account:

    • Clinical tolerance of anaemia
    • Underlying conditions (cardiovascular disease, infection, etc.)
    • Rate at which anaemia develops.
    • Hb levels

    If transfusion is indicated, it should be carried out without delay b Citation b. Before transfusing: determine the recipient’s and potential donors’ blood groups/rhesus and carry out screening tests on the donor’s blood for HIV-1 and 2, syphilis and, in endemic areas, malaria and Chagas disease. . For transfusion thresholds, see Table 2.

    Volume to be transfused

    In the absence of hypovolaemia or shock:
    Children < 20 kg: 15 ml/kg of red cell concentrate in 3 hours or 20 ml/kg of whole blood in 4 hours
    Children ≥ 20 kg and adults: start with an adult unit of whole blood or red cell concentrate; do not exceed a transfusion rate of 5 ml/kg/hour
    Repeat if necessary, depending on clinical condition.

    Monitoring

    Monitor the patient’s condition and vital signs (heart rate, blood pressure, respiratory rate, temperature):

    • During the transfusion: 5 minutes after the start of transfusion, then every 15 minutes during the first hour, then every 30 minutes until the end of the transfusion.
    • After the transfusion: 4 to 6 hours after the end of the transfusion.

     

    If signs of circulatory overload appear:

    • Stop temporarily the transfusion.
    • Sit the patient in an upright position.
    • Administer oxygen.
    • Administer furosemide by slow IV:
      Children: 0.5 to 1 mg/kg
      Adults: 20 to 40 mg
      Repeat the injection (same dose) after 2 hours if necessary.
      Once the patient has been stabilised, start the transfusion again after 30 minutes.

    Prevention

    • Iron (and folic acid) deficiency:
      • Drug supplements
        ferrous salts PO as long as the risk of deficiency persists (e.g. pregnancy [1] Citation 1. WHO. Daily iron and folic acid supplementation in pregnant women. Geneva, 2012.
        http://apps.who.int/iris/bitstream/10665/77770/1/9789241501996_eng.pdf?ua=1
        , malnutrition). Doses are expressed in elemental iron:

        Neonates: 4.5 mg once daily
        Children 1 month to < 12 years: 1 to 2 mg/kg once daily (max. 65 mg daily)
        Children ≥ 12 years and adults: 65 mg once daily

    ​​

    Age

    Weight

    Prevention
    45 mg/5 ml syrup 65 mg tablet
    < 1 month < 4 kg 0.5 ml
    1 month to < 1 year 4 to < 10 kg 1 ml
    1 to < 6 years 10 to < 20 kg 2.5 ml
    6 to < 12 years 20 to < 40 kg 5 ml
    ≥ 12 years and adults ≥ 40 kg 1 tab

     

    or preferably,
    ferrous salts + folic acid PO based on elemental iron dosages.

    • Nutritional supplements (if the basic diet is insufficient)
    • In the event of sickle cell anaemia: see Sickle cell disease (Chapter 12).
    • Early treatment of malaria, helminthic infections, etc.

     

    Table 2 - Definition of anaemia and transfusion thresholds

     

    Patients

    Hb levels defining anaemia

    Transfusion threshold

    Children 2-6 months

    < 9.5 g/dl

    Hb < 4 g/dl, even if there are no signs of decompensation

    Hb ≥ 4 g/dl and < 6 g/dl if there are signs of decompensation or sickle cell disease or severe malaria or serious bacterial infection or pre-existing heart disease

    Children 6 months-5 years

    < 11 g/dl

    Children 6-11 years

    < 11.5 g/dl

    Children 12-14 years

    < 12 g/dl

    Men

    < 12 g/dl

    Hb < 7 g/dl if there are signs of decompensation or sickle cell disease or severe malaria or serious bacterial infection or pre-existing heart disease

    Women

    < 13 g/dl

    Pregnant women

     

    < 11 g/dl
    (1st and 3rd trimester)

    < 10.5 g/dl
    (2nd trimester)

     

    < 36 weeks

    Hb ≤ 5 g/dl, even if there are no signs of decompensation

    Hb > 5 g/dl and < 7 g/dl if there are signs of decompensation or sickle cell disease or severe malaria or serious bacterial infection or pre-existing heart disease

    ≥ 36 weeks

    Hb ≤ 6 g/dl, even if there are no signs of decompensation

    Hb > 6 g/dl and < 8 g/dl if there are signs of decompensation or sickle cell disease or severe malaria or serious bacterial infection or pre-existing heart disease

     

    Footnotes
    • (a)Available in 140 mg/5 ml syrup of ferrous fumarate containing approximately 45 mg/5 ml of elemental iron and 200 mg ferrous sulfate tablets or ferrous sulfate + folic acid tablets containing 65 mg of elemental iron. Tablets of 185 or 200 mg ferrous fumurate or sulfate + folic acid (60 or 65 mg of elemental iron) contain 400 micrograms folic acid.
    • (b)Before transfusing: determine the recipient’s and potential donors’ blood groups/rhesus and carry out screening tests on the donor’s blood for HIV-1 and 2, syphilis and, in endemic areas, malaria and Chagas disease.
    References