Difference between revisions of "Thalassemia"

 
(4 intermediate revisions by 3 users not shown)
Line 1: Line 1:
 
==Background==
 
==Background==
*A group of hereditary disorders resulting in microcytic, hypochromic, hemolytic anemia
+
*A group of hereditary disorders resulting in microcytic, hypochromic, hemolytic [[anemia]]
 
*Most common in Mediterranean, Middle Eastern, African and Southeast Asian population
 
*Most common in Mediterranean, Middle Eastern, African and Southeast Asian population
  
Line 7: Line 7:
 
**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]]
*hypochromic, microcytic anemia with jaundice and hepatosplenomegaly
+
*Hypochromic, microcytic anemia with [[jaundice]] and [[hepatomegaly|hepatosplenomegaly]]
*may not require regular transfusions
+
*May not require regular [[pRBCs|transfusions]]
*tranfusions may be necessary in setting of increased oxidative stress or infection which may precipitate hemolysis
+
*[[pRBCs|Transfusions]] may be necessary in setting of increased oxidative stress or infection which may precipitate [[hemolytic anemia|hemolysis]]
 +
*Note that alpha thalassemia major (Hb Bart) results in [[hydrops fetalis]], and thus is not an adult disease process
  
'''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]]
*splenomegaly uncommon
+
*Splenomegaly uncommon
*microcytosis, hypochromia, basophilic stippling on blood smear
+
*Microcytosis, hypochromia, basophilic stippling on blood smear
*no clinical symptoms
+
*Co 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)
*hepatosplenomegaly, jaundice, expansion of erythroid marrow causing bone changes and osteoporosis, susceptible to infection
+
*[[hepatomegaly|Hepatosplenomegaly]], [[jaundice]], expansion of erythroid marrow causing bone changes and osteoporosis, susceptible to [[osteomyelitis|infection]]
*severe anemia requiring regular and lifelong blood transfusions
+
*Severe [[anemia]] requiring regular and lifelong blood [[pRBCs|transfusions]]
**iron overload secondary to frequent transfusions is etiology of most of morbidity and mortality
+
**[[hemochromatosis|Iron overload]] secondary to frequent transfusions is etiology of most of morbidity and mortality
*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
+
*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
*severity depends on type of β-thalassemia gene inherited
+
*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
 
**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
+
**10-20% inherit β-thalassemia gene that produces no-chains; these patients have severe [[hemolytic anemia]] and [[vaso-occlusive crisis|vaso-occlusive symptoms]]
  
 
==Differential Diagnosis==
 
==Differential Diagnosis==
 
===[[Anemia]]===
 
===[[Anemia]]===
 
====RBC Loss====
 
====RBC Loss====
*Hemorrhage
+
*[[Hemorrhage]]
 
====RBC consumption (Destruction/hemolytic)====
 
====RBC consumption (Destruction/hemolytic)====
 
*Hereditary  
 
*Hereditary  
Line 60: Line 61:
 
*Chemicals (e.g. [[ETOH]])
 
*Chemicals (e.g. [[ETOH]])
 
*Radiation
 
*Radiation
*Infection ([[HIV]], parvo)
+
*Infection ([[HIV]], [[parvovirus B19|parvo]])
 
====Megaloblastic (macrocytic)====
 
====Megaloblastic (macrocytic)====
 
*Vitamin B12/folate deficiency
 
*Vitamin B12/folate deficiency
Line 77: Line 78:
 
*Identify and discontinue precipitating agent
 
*Identify and discontinue precipitating agent
 
*Supportive care  
 
*Supportive care  
*Blood transfusions for severe anemia
+
*[[pRBCs|Blood transfusions]] for severe anemia
  
 
==Disposition==
 
==Disposition==

Latest revision as of 18:47, 1 October 2019

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
  • Transfusions may be necessary in setting of increased oxidative stress or infection which may precipitate hemolysis
  • Note that alpha thalassemia major (Hb Bart) results in hydrops fetalis, and thus is not an adult disease process

β-Thalassemia Minor (β-Thalassemia Trait)

  • Heterozygous for β-globin mutation
  • Mild microcytic anemia
  • Splenomegaly uncommon
  • Microcytosis, hypochromia, basophilic stippling on blood smear
  • Co 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

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