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Thalassaemia and sickle cell disease in children
Haemoglobinopathies are diseases of the haemoglobin chains: in thalassaemia too little is made (microcytic anaemia and, in the severe form, transfusion dependence and iron overload), and in sickle cell disease an abnormal haemoglobin is made that causes vaso-occlusion, haemolysis and loss of splenic function.
Why it matters in the exam
The basic question is separating beta-thalassaemia trait from iron deficiency: both have a low MCV, but in the trait the red cell count is normal or high, the Mentzer index (MCV divided by RBC) is below 13, ferritin is normal and HbA2 is above 3.5% on electrophoresis. Iron is not given to a carrier. In Israel thalassaemia is common in some communities, and carrier screening is offered before or early in pregnancy.
Beta-thalassaemia major appears at 6–24 months, as fetal haemoglobin falls: severe anaemia, hepatosplenomegaly, facial bone changes and failure to thrive. Treatment is regular transfusion (pre-transfusion haemoglobin 9.5–10.5 g/dL) and iron chelation when ferritin rises above 1000 ng/mL or after 10–20 transfusions; stem cell transplantation is curative.
In sickle cell disease the exam asks about crises: dactylitis (painful swollen hands and feet) as a first sign at 6 months to two years; acute chest syndrome (fever, chest pain and a new infiltrate — antibiotics including a macrolide, oxygen and sometimes transfusion); splenic sequestration (a rapidly enlarging spleen and a falling haemoglobin); aplastic crisis from parvovirus B19 (low reticulocytes); and stroke. A child with a fever of 38.5°C or more is an emergency because of lost splenic function: blood culture and ceftriaxone. Prevention includes penicillin from 2 months to 5 years, vaccines, transcranial Doppler at age 2–16 and hydroxyurea from 9 months.
Key points
- Beta-thalassaemia trait: Mentzer below 13, HbA2 above 3.5%, normal ferritin.
- Thalassaemia major: age 6–24 months; transfusion and chelation.
- Sickle cell disease: fever = emergency; culture and ceftriaxone.
- Acute chest syndrome: fever, chest pain, new infiltrate.
- Prevention: penicillin to age 5, transcranial Doppler, hydroxyurea.
Summary table
| Condition | Laboratory or finding | Presentation | Treatment |
|---|---|---|---|
| Beta-thalassaemia trait | Low MCV, normal-high RBC, Mentzer below 13, HbA2 above 3.5%, normal ferritin | Mild or no anaemia | Genetic counselling; no iron |
| Beta-thalassaemia major | Severe anaemia, high HbF | Age 6–24 months, hepatosplenomegaly, bone changes | Regular transfusion, iron chelation, stem cell transplantation |
| Alpha-thalassaemia | 1 gene — silent; 2 — trait; 3 — HbH; 4 — hydrops | HbH: haemolysis and moderate anaemia | By severity; genetic counselling |
| Sickle cell disease — fever | Loss of splenic function | Risk of pneumococcal sepsis | Blood culture and ceftriaxone at once |
| Sickle cell disease — crises | Acute chest, splenic sequestration, aplastic crisis, stroke | Pain, hypoxaemia, enlarging spleen, low reticulocytes | Antibiotics, oxygen, transfusion, hydration and analgesia |
| Sickle cell disease — prevention | Transcranial Doppler at age 2–16 | Velocity above 200 cm/s = stroke risk | Penicillin to age 5, vaccines, hydroxyurea, chronic transfusion when stroke risk is high |
A free exam question
בן 7 ( שנים שלוקה באנמיה חרמשית Sickle cell ) מאושפז עקב חום עד 39 מ"צ וצמיחה בדם של Salmonella spp. . איזו? בדיקת דימות מומלץ לבצע (the question as examined, in Hebrew)
- א. מיפוי כליות
- ב. אולטרסאונד בטן
- ג. מיפוי עצמות
- ד. צילום בית חזה
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Sources
- Thalassaemia International Federation: Guidelines for the Management of Transfusion Dependent Thalassaemia, 4th edition (2021) — Transfusion targets and iron chelation
- NHLBI Evidence-Based Management of Sickle Cell Disease: Expert Panel Report, 2014 — Hydroxyurea, transcranial Doppler and penicillin prophylaxis
- Nelson Textbook of Pediatrics, 22nd edition (2024) — Hemoglobinopathies
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.