31 August 2026Chapter 1: A few symptoms and syndromesPDF page 45Source update: January 2024
Anaemia
Clinical guide to anaemia symptoms, common causes, transfusion warning signs, and prevention basics.
This guide supports clinical education and care navigation. It does not replace bedside judgement, emergency care, specialist advice, or local treatment protocol.
Seek urgent care
- Severe weakness, breathlessness at rest, fainting, chest pain, shock signs, altered consciousness, or heart failure signs.
- Anaemia in pregnancy, young infants, severe malaria, bleeding, severe malnutrition, or sickle cell disease.
- Pale child with fast breathing, inability to drink, lethargy, or very low haemoglobin when testing is available.
Definition and causes
Anaemia is haemoglobin below the expected reference range for age, sex, and pregnancy status. The clinical danger is reduced oxygen delivery, especially when anaemia develops quickly or the patient has infection, pregnancy, heart disease, respiratory disease, malaria, severe malnutrition, or bleeding.
Causes often overlap. Reduced red-cell production, blood loss, and haemolysis can occur together, so do not stop at a single explanation when the presentation is severe or recurrent.
| Mechanism | Examples |
|---|---|
| Reduced red-cell production | Iron deficiency, folate deficiency, vitamin B12 deficiency, vitamin A deficiency, bone marrow suppression, HIV, visceral leishmaniasis, renal failure. |
| Blood loss | Acute haemorrhage, gastrointestinal ulcer, hookworm, schistosomiasis, menstrual or obstetric bleeding, trauma. |
| Increased destruction | Malaria, HIV and other infections, sickle cell disease, thalassaemia, and drug-triggered haemolysis in G6PD deficiency. |
Clinical features
- Common signs: conjunctival, mucosal, palmar, or plantar pallor; fatigue; dizziness; dyspnoea; tachycardia; heart murmur; poor feeding; weakness; reduced exercise tolerance.
- Signs of decompensation: cold extremities, altered mental status, respiratory distress, oedema of the lower limbs, elevated jugular venous pressure, cardiac or coronary failure, and shock.
- Clues to specific causes include cheilosis or glossitis for nutritional deficiency, jaundice or dark urine for haemolysis, hepatosplenomegaly, melaena, haematuria, malaria signs, worm exposure, chronic inflammation, or inherited blood disorder history.
- Clinical tolerance depends on speed of onset, haemoglobin level, age, pregnancy, infection, cardiovascular disease, respiratory disease, and ongoing blood loss.
Laboratory assessment
- Measure haemoglobin whenever available. Interpret the result against age, sex, and pregnancy status.
- In malaria-endemic settings, perform malaria rapid diagnostic test or thick and thin blood films.
- Use urine dipstick to look for haemoglobinuria or haematuria.
- If sickle cell disease is suspected and transfusion is being considered, perform a rapid sickle test or Emmel test before transfusion when available.
- Full blood count helps classify anaemia and direct the search for cause.
| Pattern | Possible diagnoses |
|---|---|
| Macrocytic anaemia | Folate deficiency, vitamin B12 deficiency, chronic alcohol use. |
| Microcytic anaemia | Iron deficiency from malnutrition or chronic bleeding, chronic inflammation, HIV infection, cancer, thalassaemia. |
| Normocytic anaemia | Acute haemorrhage, renal failure, haemolysis. |
| Reduced reticulocytes | Iron, folate, or vitamin B12 deficiency; marrow disease; renal failure. |
| Normal or increased reticulocytes | Haemolysis, sickle cell disease, thalassaemia, or recent blood loss. |
| Eosinophilia | Hookworm, trichuriasis, schistosomiasis, HIV infection, or malignant haematological disease. |
Haemoglobin thresholds
- A child 2 months to 12 years with Hb 4 to under 6 g/dl and no decompensation or ongoing blood loss may not need immediate transfusion if close monitoring and transfusion preparation are reliable.
- Thresholds must be interpreted with the full clinical picture; do not delay transfusion when indicated.
| Patient | Anaemia definition | Transfusion threshold |
|---|---|---|
| Children 2 to 6 months | Hb less than 9.5 g/dl | Hb less than 4 g/dl even without decompensation, or Hb 4 to under 6 g/dl with decompensation, ongoing blood loss, severe malaria, serious bacterial infection, or heart disease. |
| Children 6 months to 4 years | Hb less than 11 g/dl | Same child transfusion threshold pattern. |
| Children 5 to 11 years | Hb less than 11.5 g/dl | Same child transfusion threshold pattern. |
| Children 12 to 14 years | Hb less than 12 g/dl | Same child transfusion threshold pattern. |
| Men 15 years and over | Hb less than 13 g/dl | Hb less than 7 g/dl with decompensation, ongoing blood loss, severe malaria, serious bacterial infection, or heart disease. |
| Women 15 years and over | Hb less than 12 g/dl | Adult threshold pattern as above. |
| Pregnancy, first or third trimester | Hb less than 11 g/dl | Under 36 weeks: Hb 5 g/dl or below, or Hb over 5 to under 7 g/dl with decompensation or major risk. From 36 weeks: Hb 6 g/dl or below, or Hb over 6 to under 8 g/dl with decompensation or major risk. |
| Pregnancy, second trimester | Hb less than 10.5 g/dl | Use pregnancy gestation thresholds above. |
Aetiological treatment
Anaemia alone is not automatically an indication for transfusion. Most anaemias are corrected by treating the cause, with or without transfusion when severe.
- Treat helminth infection, schistosomiasis, malaria, HIV, visceral leishmaniasis, renal disease, chronic inflammation, or bleeding source according to the relevant protocol.
- When anaemia is associated with malaria and iron deficiency, treat malaria first and wait about 4 weeks before starting iron supplementation.
- If haemolytic anaemia is suspected, stop drugs that can trigger haemolysis in known or possible G6PD deficiency, such as primaquine, dapsone, co-trimoxazole, or nitrofurantoin.
| Age | Dose direction | Common practical dose |
|---|---|---|
| 1 month to under 6 years | 1.5 to 3 mg/kg twice daily for 3 months | 45 mg/5 ml syrup: 1.5 ml twice daily for 4 to under 10 kg; 2.5 ml twice daily for 10 to under 20 kg. |
| 6 to under 12 years | 65 mg twice daily for 3 months | 60 or 65 mg tablet: 1 tablet twice daily. |
| 12 years and over and adults | 65 mg two to three times daily for 3 months | 60 or 65 mg tablet: 1 tablet two or three times daily. |
| Patient | Dose direction |
|---|---|
| Children under 1 year | Folic acid 0.5 mg/kg once daily for 4 months. |
| Children 1 year and over and adults | Folic acid 5 mg once daily for 4 months. |
Blood transfusion
Before transfusion, determine recipient and donor blood group/rhesus and screen donor blood for HIV 1 and 2, hepatitis B and C, syphilis, and locally relevant infections such as malaria or Chagas disease when applicable.
- If haemorrhagic shock is present, follow the shock protocol.
- Transfuse without delay when thresholds and clinical state indicate transfusion.
- Monitor heart rate, blood pressure, respiratory rate, and temperature 5 minutes after starting, every 15 minutes during the first hour, every 30 minutes until completion, then 4 to 6 hours after the end.
- Watch for transfusion reaction, fluid overload, decompensation, or continuing blood loss.
- For children, repeat haemoglobin 8 to 24 hours after transfusion or sooner if decompensation or continuing blood loss occurs.
- If circulatory overload develops, stop transfusion temporarily, sit the patient upright, give oxygen, give slow IV furosemide when indicated, and restart cautiously after stabilisation.
| Patient | If no fever | If fever is present |
|---|---|---|
| Children | Packed red cells 15 ml/kg over 3 hours, or whole blood 30 ml/kg over 4 hours. | Packed red cells 10 ml/kg over 3 hours, or whole blood 20 ml/kg over 4 hours. |
| Adolescents and adults | Start with one adult unit of packed red cells or whole blood. | Start with one adult unit and do not exceed 5 ml/kg/hour. |
Prevention and follow-up
- Prevention may be needed during pregnancy, malnutrition, poor dietary intake, heavy menstrual loss, recurrent malaria, helminth exposure, or chronic disease.
- Use nutritional supplementation when the basic diet is insufficient.
- Prevent and treat malaria, hookworm, schistosomiasis, trichuriasis, chronic bleeding, and pregnancy-related deficiency risks.
- Follow haemoglobin response, adherence, side effects, ongoing bleeding, recurrent infection, and need for further investigation if anaemia does not improve.
| Age | Dose direction | Common practical dose |
|---|---|---|
| 1 month to under 12 years | 1 to 2 mg/kg once daily, maximum 65 mg/day while risk persists. | 45 mg/5 ml syrup: 1 ml daily for 4 to under 10 kg; 2.5 ml daily for 10 to under 20 kg; 5 ml daily for 20 to under 40 kg. |
| 12 years and over and adults | 65 mg once daily while risk persists. | 60 or 65 mg tablet: 1 tablet daily. |
Complications and referral
- Complications include heart failure, shock, myocardial ischaemia, respiratory distress, impaired growth and development in children, maternal and fetal complications, transfusion reaction, and fluid overload.
- Refer urgently for signs of decompensation, severe anaemia requiring transfusion, pregnancy near term with severe anaemia, sickle cell crisis, suspected haemolysis, ongoing bleeding, severe malaria, serious bacterial infection, severe malnutrition, renal failure, or unclear cause after initial evaluation.
- Handover should include haemoglobin value, pregnancy status, age, decompensation signs, suspected cause, malaria result, urine findings, FBC pattern, transfusion status, blood product volume, medicines started, and response to treatment.
Medicines in this guide
Ferrous salts/Folic acid oralPreferred combined treatment or prevention option when iron and folate deficiency risk is present.Ferrous salts oralIron replacement option when combined iron/folate is not available or not indicated.Folic acid = Vitamin B9 oralTreatment for folate deficiency and prevention in pregnancy or other high-risk states.Albendazole oralDeworming option where helminth infection contributes to anaemia.Mebendazole oralAlternative deworming medicine for nematode infections where appropriate.Praziquantel oralTreatment option for schistosomiasis-related blood loss where indicated.Furosemide injectableUsed for transfusion-associated circulatory overload when clinically indicated.
Source
MSF Clinical guidelines - Diagnosis and treatment manual (December 2024)
This page is a paraphrased clinician-oriented guide derived from the source topic on PDF page 45. Medicine-specific details should be checked against local protocol and the linked drug-information pages.