thalassemia
| inherited microcytic anaemia, >1% across Mediterranean/Middle East/SEA/N Africa/India against malaria | |
|---|---|
| Etiology | Alpha thalassaemia: deletion or loss of function of alpha genes - loss of all 4 = hydrops fetalis = fatal - haemoglobin H = loss/dysfunction of 3 a-genes Beta thalassaemia: mutation in beta globin gene → ↓ synthesis of beta globin |
| Epidemiology | more common in Mediterranean to Far East (地中海贫血) |
| Clinical presentation | anaemia, hepatosplenomegaly, failure to thrive, mild jaundice, features of iron overload, "recurrent infections" due to Fe overload? Radiology: BM expansion: extramedullary erythropoiesis*; skull bossing, hepatosplenomegaly, “hair on end” sign in skull XR (also in infiltrative conditions e.g. leukaemia) |
| Pathogenesis | Ineffective erythropoiesis, extramedullary haematopoiesis |
| Diagnostic investigations | FBC: microcytic anaemia, ↑ HbA2 Blood film: microcytosis, tear drop cells, target cells, nucleated red cells |
| Management | ➥ If symptomatic: regular transfusions + iron chelation ➥ S/s iron overload: deposition in… ➥➥ Hypothyroid ➥➥ pancreas: monitor with OGTT, exocrine dysfunction ➥➥ heart: restrictive cardiomyopathy, arrhy ➥➥ pituitary: hypogonadism ➥ chelation: monitor kidney function ➥ Genetic counselling ➥ Screening for all pregnant ppl + newborns (part of blood spot screening) |
classic lab findings
- bone marrow: hypercellular, erythroid hyperplasia