Thalassemia

Thalassemia

Thalassemia is a hypochromic microcytic anemia with inherited abnormalities of globin genes. Thalassemia is common in the Mediterranean countries, the Middle East and South Asia. Types

• • a-Thalassemia is caused by a lack of synthesis of the a-chain of globin. Predominant in Asian states. For the final diagnosis, a detailed and in-depth test of Ho circuits will need to be carried out. In newborns, Hb Barth is found during electrophoresis of blood from the umbilical cord. The content of HbA2 and HbF is traditionally not increased.
  • division of four genes. Failure to produce any α-globin chain results in an excess of y-globin chains forming Hb tetramers, referred to as Barth’s Hb. Hb Barth has a powerful affinity for oxygen, which interferes with tissue respiration – severe anemia, heart failure, hepato- and splenomegaly, generalized edema develop, and intrauterine death begins as a result of fetal dropsy.
  • Deletions of three genes (HbH disease, Hb hemoglobinopathies). Despite the presence of severe anemia and an increased content of Hb Barth, the number of a-globin sufficient for the development of the fetus appears. Throughout life, the patient retains anemia, ranging from moderate to severe. In the postnatal period, HbH prevails.
  • Deletions of 2 genes (thalassemia minor). Moderate hypochromic microcytic anemia. Thalassemia minor is sometimes misdiagnosed as IDA.
  • Deletion of one gene (state of healthy carriage). The usual picture of peripheral blood is characteristic, including the usual concentrations of Hb, Ht and the number of erythrocytes. Pathology is detected by quantitative measurement of globin chains or by a genome test. The carrier may experience an exacerbation of HbH disease or thalassemia minor.
  • B-thalassemia (more than 90% of all thalassemias) develops as a result of the expression of abnormal B-globin chain genes. Since there are two B-globin alleles in the genome, there are two possible forms of B-thalassemia.
  • Homozygous B-thalassemia (thalassemia major, Cooley’s anemia) is a severe disease that manifests itself in childhood and ends fatally by the age of 20; patients are traditionally transfusiosis-dependent. It is clinically manifested by growth retardation, hepatosplenomegaly, noncordial jaundice, bone marrow hyperplasia and bone deformity. The content of HbA2 is reduced or increased, HbF is significantly increased.
  • Heterozygous B-thalassemia (thalassemia minor) is traditionally mild anemia, patients do not depend on transfusions. Thalassemia minor is common in Italy and Greece. In the lowland regions of Azerbaijan, 7-11% of the population suffers from it. The content of HbA2 is increased, HbF is normal or slightly elevated. Genetic Aspects
  • a-thalassemia (* 141800, 16p, damage to the genes HBAC, HBA1, HBA2, HbHR, R)
  • B-thalassemias (*141900, 11p15.5, R).

Pathogenesis

• • An excess of unpaired globin chains induces the formation of insoluble tetramers that are absorbed on erythrocyte membranes and damage them. Erythroid cells become susceptible to destruction by phagocytes of the bone marrow (hence defective erythropoiesis) or the liver and spleen (hence hemolytic anemia)
  • Note the relative deficiency of folic acid.

Clinical picture

• • hypochromic anemia
  • Secondary hemochromatosis due to unreasonable use of pre-

iron paraates and frequent blood transfusions

• • Hemolytic jaundice, cholelithiasis and splenomegaly
  • Joint damage
  • With thalassemia major – arthritis of the ankle joints, thalalgia; the development of secondary gouty arthritis is likely; aseptic bone necrosis is uncharacteristic
  • In thalassemia minor, brief bouts of synovitis of large joints without fever, extra-articular symptoms, or deformities.

Diagnostics

• • The main diagnostic criteria are microcytosis, hypochromia, poikilocytosis (elliptocytosis)
  • Depending on the predominance of hemolysis or defective erythropoiesis, a decrease or increase in the number of reticulocytes is observed.
  • A decrease in the number of erythrocytes traditionally does not occur (an important differential diagnostic sign)
  • Minor B-thalassemia – an increase in the concentration of HbA2 (5% compared to 2.5% normal)
  • B-thalassemia major is a significant increase in the HbF fraction. Differential Diagnosis
  • IDA
  • hemolytic anemia.

Treatment:

• • Repeated transfusions of washed or thawed RBCs
  • Deferoxamine (desferal) 0.5-1 g/day – with regular use, forming a complex compound with excess iron, slows down the development of hemosiderosis
  • Folic acid nbsp; 0.1-0.2 mg / day
  • Antibiotic therapy – when an infection is attached
  • Bone marrow transplantation and splenectomy – according to indications.

Complications

• • infections
  • Trophic ulcers of the extremities
  • pathological fractures
  • Hemosiderosis of the liver and heart
  • Aplastic or megaloblastic crisis.

Synonym. Target cell hemolytic anemia 1-16 ICD D56 Thalassemia MSH

• • 141800 a-thalassemia
  • 141900 B-Thalassemia