Difference between revisions of "Thalassemia"

(Created page with "==Background== *A group of hereditary disorders resulting in microcytic, hypochromic, hemolytic anemia *Most common in Mediterranean, Middle Eastern, African and Southeast Asi...")
 
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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
+
'''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)
+
'''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)
+
'''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)
+
'''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
+
'''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
ɑ
+
*1 per 1600 African American births
β
+
*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==
 
==Differential Diagnosis==
 +
===[[Anemia]]===
 +
====RBC Loss====
 +
*Hemorrhage
 +
====RBC consumption (Destruction/hemolytic)====
 +
*Hereditary
 +
**[[Sickle cell disease]]
 +
**[[Glucose-6-phosphate deficiency]]
 +
*Acquired
 +
*[[Microangiopathic Hemolytic Anemia (MAHA)]]
 +
*[[Autoimmune hemolytic anemia]]
 +
====Impaired Production (Hypochromic/microcytic)====
 +
*Iron deficiency
 +
*Anemia of chronic disease
 +
*[[Thalassemia]]
 +
*Sideroblastic anemia
 +
====Aplastic/myelodysplastic (normocytic)====
 +
*Marrow failure
 +
*Chemicals (e.g. [[ETOH]])
 +
*Radiation
 +
*Infection ([[HIV]], parvo)
 +
====Megaloblastic (macrocytic)====
 +
*Vitamin B12/folate deficiency
 +
*Drugs (chemo)
 +
*[[HIV]]
  
 
==Evaluation==
 
==Evaluation==
 +
*CBC
 +
*CMP
 +
*Blood smear
 +
*Reticulocyte count
 +
*LDH
 +
*Haptoglobin
  
 
==Management==
 
==Management==
 +
*Identify and discontinue precipitating agent
 +
*Supportive care
 +
*Blood transfusions for severe anemia
  
 
==Disposition==
 
==Disposition==
  
 
==See Also==
 
==See Also==
 +
*[[Anemia]]
  
 
==External Links==
 
==External Links==
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==References==
 
==References==
 
<references/>
 
<references/>
 +
*Tintinalli's Emergency Medicine 7th Edition, pg1486-7
 +
 +
[[Category: Heme/Onc]]

Revision as of 22:39, 26 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)

Impaired Production (Hypochromic/microcytic)

  • Iron deficiency
  • Anemia of chronic disease
  • Thalassemia
  • Sideroblastic anemia

Aplastic/myelodysplastic (normocytic)

  • Marrow failure
  • Chemicals (e.g. ETOH)
  • Radiation
  • Infection (HIV, parvo)

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