Anaemia

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

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

or preferably,
ferrous salts + folic 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

​​

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