Differentiating Alpha from Beta Thalassemias
BETA THALASSEMIA SYNDROMES:
"blacks, Greeks and Italians"
1.- Major beta thalassemia
- Skeletal changes : "chipmunk facies", delayed skeletal maturation and "hair-on-end" radiographic appearance of the skull.
- Hepatomegaly is prominent early in the disease + massive splenomegaly
- Endocrine and metabolic abnormalities*(quite common) attributable, at least in part, to chronic iron overload.
Hypogonadism 40 percent, Growth failure 33 percent, Diabetes 13 percent & Hypothyroidism 10 percent.
- Cardiac malfunction, including heart failure and fatal arrhythmias, are frequent causes of death, and cardiac dilatation secondary to anemia is nearly universal.
basic lab: profound hypochromic, microcytic anemia (MCV < 65 fL) & target cell
2.- Beta thalassemia minor (or beta thalassemia trait / silent carrier of beta thalassemia = heterozygotes who carry one normal beta globin allele and one beta globin thalassemic allele.)
The vast majority of these patients are entirely asymptomatic.
Typically, the blood count and peripheral blood film exhibit features similar to those seen in iron deficiency anemia (eg, hypochromia and microcytosis), but this patients almost always have a hematocrit >30 percent, and a mean corpuscular volume of the red cells (MCV) <75 fL. We also can see target and tear drop shaped red cells.
ALPHA THALASSEMIA SYNDROMES:
"blacks and Southeast Asians"
1.- Alpha thalassemia-2 trait (aka alpha thalassemia minima aa/a-): Patients are asymptomatic. The complete blood count, hemoglobin electrophoresis, and peripheral smear are usually normal.
2.- Alpha thalassemia-1 trait (aka alpha thalassemia minor) resembles mild beta thalassemia trait.
3.- Hemoglobin H disease: This patients suffer from hemolytic anemia throughout much of gestation and are symptomatic at birth, often presenting with neonatal jaundice and anemia, and occasionally with hydrops fetalis. This occurs because alpha globin synthesis is required in utero for the production of the major hemoglobin found during late gestation: hemoglobin F (alpha2/gamma2). Patients with beta thalassemia, on the other hand, do not have these difficulties until a few months after birth, when hemoglobin F production decreases markedly and there is a need for increased production of beta chains for hemoglobin A (alpha2/beta2).
4.- Hydrops fetalis and hemoglobin Barts is usually fatal in utero.
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