Thalassemia: Difference between revisions
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**β-globin gene mutations cause β-thalassemia; ɑ-globin mutations cause ɑ-thalassema | **β-globin gene mutations cause β-thalassemia; ɑ-globin mutations cause ɑ-thalassema | ||
===ɑ-Thalassemia Carrier and Trait=== | |||
*no clinical symptoms or physical findings | *no clinical symptoms or physical findings | ||
*microcytic RBCs and normal Hb level | *microcytic RBCs and normal Hb level | ||
===Hemoglobin H Disease (HbH disease)=== | |||
*one ɑ-globin chain gene is still functional | *one ɑ-globin chain gene is still functional | ||
*typically presents in neonatal period with severe hypochromic anemia | *typically presents in neonatal period with severe hypochromic anemia | ||
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*tranfusions may be necessary in setting of increased oxidative stress or infection which may precipitate hemolysis | *tranfusions may be necessary in setting of increased oxidative stress or infection which may precipitate hemolysis | ||
===β-Thalassemia Minor (β-Thalassemia Trait)=== | |||
*heterozygous for β-globin mutation | *heterozygous for β-globin mutation | ||
*mild microcytic anemia | *mild microcytic anemia | ||
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*no clinical symptoms | *no clinical symptoms | ||
===β-Thalassemia Major (Cooley Anemia)=== | |||
*both β-globin genes defective; β-globin chain production severely impaired | *both β-globin genes defective; β-globin chain production severely impaired | ||
*typically presents >6mos of life (HbF production replaced with β-globin to form HbA) | *typically presents >6mos of life (HbF production replaced with β-globin to form HbA) | ||
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*low MCV with microcytic and hypochromic RBC | *low MCV with microcytic and hypochromic RBC | ||
===Sickle Cell-β-Thalassemia Disease=== | |||
*gene for sickle Hb is inherited from one parent and gene for β-thalassemia is inherited from the other parent | *gene for sickle Hb is inherited from one parent and gene for β-thalassemia is inherited from the other parent | ||
*1 per 1600 African American births | *1 per 1600 African American births |
Revision as of 17:28, 27 September 2016
Background
- A group of hereditary disorders resulting in microcytic, hypochromic, hemolytic anemia
- Most common in Mediterranean, Middle Eastern, African and Southeast Asian population
Clinical Features
- Categorized depending on globin chain affected or the abnormal Hb produced
- β-globin gene mutations cause β-thalassemia; ɑ-globin mutations cause ɑ-thalassema
ɑ-Thalassemia Carrier and Trait
- no clinical symptoms or physical findings
- microcytic RBCs and normal Hb level
Hemoglobin H Disease (HbH disease)
- one ɑ-globin chain gene is still functional
- typically presents in neonatal period with severe hypochromic anemia
- hypochromic, microcytic anemia with jaundice and hepatosplenomegaly
- may not require regular transfusions
- tranfusions may be necessary in setting of increased oxidative stress or infection which may precipitate hemolysis
β-Thalassemia Minor (β-Thalassemia Trait)
- heterozygous for β-globin mutation
- mild microcytic anemia
- splenomegaly uncommon
- microcytosis, hypochromia, basophilic stippling on blood smear
- no clinical symptoms
β-Thalassemia Major (Cooley Anemia)
- both β-globin genes defective; β-globin chain production severely impaired
- typically presents >6mos of life (HbF production replaced with β-globin to form HbA)
- hepatosplenomegaly, jaundice, expansion of erythroid marrow causing bone changes and osteoporosis, susceptible to infection
- severe anemia requiring regular and lifelong blood transfusions
- iron overload secondary to frequent transfusions is etiology of most of morbidity and mortality
- low MCV with microcytic and hypochromic RBC
Sickle Cell-β-Thalassemia Disease
- gene for sickle Hb is inherited from one parent and gene for β-thalassemia is inherited from the other parent
- 1 per 1600 African American births
- severity depends on type of β-thalassemia gene inherited
- 80-90% inherit β-thalassemia gene that has some normal β-chain production; these patients have mild hemolytic anemia with near-normal Hb levels, few crises
- 10-20% inherit β-thalassemia gene that produces no-chains; these patients have severe hemolytic anemia and vaso-occlusive symptoms
Differential Diagnosis
Anemia
RBC Loss
- Hemorrhage
RBC consumption (Destruction/hemolytic)
- Hereditary
- Acquired
- Microangiopathic Hemolytic Anemia (MAHA)
- Autoimmune hemolytic anemia
Impaired Production (Hypochromic/microcytic)
- Iron deficiency
- Anemia of chronic disease
- Thalassemia
- Sideroblastic anemia
Aplastic/myelodysplastic (normocytic)
Megaloblastic (macrocytic)
- Vitamin B12/folate deficiency
- Drugs (chemo)
- HIV
Evaluation
- CBC
- CMP
- Blood smear
- Reticulocyte count
- LDH
- Haptoglobin
Management
- Identify and discontinue precipitating agent
- Supportive care
- Blood transfusions for severe anemia
Disposition
See Also
External Links
References
- Tintinalli's Emergency Medicine 7th Edition, pg1486-7