Beta thalassemia is a blood disorder
Pathophysiology of Beta Thalassemia
1) abnormal conversion of fetal hemoglobin to adult hemoglobin due to defective biosynthesis of globin chain
2) patients can be homozygous (major) or heterozygous (mine or trait) for the gene
Signs and Symptoms
1) failure to thrive
2) jaundice
3) icterus
4) gallstones
5) pallor under tongue
6) shortness of breath
7) “chipmunk” facies
8) leg ulcers
9) congestive heart failure
10) inanition
11) recurrent infections
12) bone and joint abnormalities (especially ankle pain)
13) “hair on end” skull
Characteristic Test Findings
Laboratory –
1) increased unconjugated bilirubin
2) hemolytic anemia
3) hypochromia
4) microcytosis
5) increased levels of bF and HbA2
Radiology –
6) osteopenia of foot
7) coarse trabeculations in ankle joints
Histology/Gross Pathology
1) hypochromic microcytic anemia
2) target cells
3) teardrop-shaped red blood cells
4) erythroid hyperplasia with erythropoietic deposits in liver and spleen
5) massive bone marrow expansion
6) hepatomegaly
Associated Conditions
1) glucose intolerance
2) endocrine disorders
3) cardiac failure due to secondary hemochromatosis
Biochemistry
caused by impaired globin synthesis my mRNA
Inheritance/Epidemiology
1) highest rate in people of Mediterranean descent
2) heterozygotes relatively common in India, central Africa, and Asia
3) especially common in areas where malaria is endemic
4) death usually by age 30 years if not treated with bone marrow transplanation
Treatment
1) chronic transfusions
2) splenectomy
3) folic acid supplements
4) bone marrow transplantation
Tips for USMLE
1) usually presents clinically around 6 months of age with a previously normal birthweight infant now in the lower 5%-10% in birthweight and height
2) beta thalassemia major is homozygous with significant clinical disease
3) beta thalassemia intermediate is homozygous with less severe clinical disease
4) beta thalassemia minor is heterozygous
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