Hemoglobinopathies Sickle cell Thalssemia Diagnosis Treatment

Causes of Hemoglobinopathies Blood

  • disorders Syndromes Diagnosis Treatment —

 

Hemoglobmopathies

Hemoglobinopathies

  • Oxygen is delivered to tissues by hemoglobin. Hemoglobin is present in erythrocytes in high con­centration and is responsible for the shape of the cell, viscosity of blood and cell deformability.
  • Hemoglobinopathies are disorders of structure, func­tion or production of hemoglobin.
  • Different hemoglobins are produced during embry­onic, fetal and adult life.
  • The major adult hemoglobin HbA has the structure  a2b2
  • Minor adult hemoglobin is HbA2,a2d2
  • HBF or fetal hemoglobin is —a2g2
  • HbF predominates during gestation.
  • During post natal life, only small amounts of HBF is present.
  • At about 6 wks of gestation, the Hb is mainly embry­onic Hb.
  • At 10 – 11 weeks, HbF becomes predominant. At 38 wks most of the Hb is HbA.
  • During stress, as in hemolytic anaemias, bone mar­row transplant, chemotherapy, HbF increases.
  • Hydroxyurea also increases HbF.

Classification of Hemoglobmopathies —

I. Structural hemoglobinopathies–

  • 1. Sickle cell anaemia – HbS
  • 2. Polycythemia, cyanosis
  • 3. Hemolytic anaemia
  • 4. Jaundice
  • 5. Methemoglobinemia.

II. Thalassemia –

  • Alpha thalassemia,
  • Beta thalas­semia,
  • Alpha-beta thalassaemia.

III. Thalassemic variants

  • HbE thalassemia
  • – Hb Lepore

IV. HPFH –

  • Hereditary persistence of fetal hemo­globin in adult life.

V. Acquired hemoglobinopathies

  • 1. Methemoglobinemia
  • 2. Sulfhemoglobinemia
  • 3. Carboxyhemoglobinemia.

Diagnosis of Hemoglobmopathies — 

  • is by haemoglobin electrophoresis and sickling tests.

The SICkLE CELL SYNDROMES —

sickle cell anaemia

SICkLE CELL

  • These are hemoglobinopathies with abnormal hemo­globin HbS.
  • The cells are sickle-shaped, non-pliable and there­fore cause vascular occlusion. The cells are easily destroyed leading to hemolytic anaemia. The cells are rigid and cause occlusion of capillaries and veins caus­ing tissue ischemia, pain, damage and infarction of organs.
  • Sickle-cell anaemia is the homozygous state for HbS.

Clinical manifestations of Hemoglobmopathies —

  • are anaemia, hemolysis, vascular occlusions, pain in limbs, renal failure, acute chest syndrome, chest pain, tachypnea, fever, cough, pulmonary embolization, cor-pulmonale.
  • The most common clinical manifestation is recurrent acute pain, fever, and tachycardia called painful cri­ses. Repeated crises more than 3 per year require hospitalisation and have bad prognosis.
  • The spleen may disappear within 3 years of life due to repeated microinfarction.
  • The hand-foot syndrome is due to painful infarct in the digits.
  • Sickle cell trait is asymptomatic, because HbS/A is 60/40.

THALASSEMIA SYNDROMES —

 

thalassemia anemia

THALASSEMIA

  • These are inherited disorders of alpha or beta globin synthesis. There is hypochromia and microcytosis.

Clinical manifestations of thalssemia syndromes —

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pattern of thalsemia syndromes

Clinical manifestations of thalssemia

  • are deranged growth and development, anaemia, chipmunk facies with maxil­lary marrow hyperplasia, frontal bossing, thin long bones, growth retardation, hemolytic anaemia, hepatosplenomegaly, and congestive heart failure.
  • Chronic transfusions with RBCs prolong life but iron overload occurs and death can occur in 3rd decade.
  • Alpha thalassemia syndromes may be asymptomatic or have hemolytic anaemia.
  • Patients of beta thalassemia minor and beta thalas­semia trait are asymptomatic.
  • Treatment consists of chronic blood and RBC transfu­sion, and splenectomy.
  • Splenectomy is recommended if several transfusions are required in a year.
  • Folic acid supplements and vaccination with pneumovax is done before splenectomy.
  • Antenatal diagnosis is now widely available. PCR am­plification of fetal DNA is used for specific diagnosis.

Treatment of Hemoglobmopathies —

  • of sickle cell syndrome is analgesics, antibiotics, morphine, oxygen therapy, blood trans­fusion.
  • Hydroxyure a 10 mg/kg/day increases fetal hemoglo­bin and is helpful.
  • Other drugs are azacytidine and decitabine.
  • Bone marrow transplantation is curative in children. Gene therapy may provide the best treatment.

This is short description about Hemoglobinopathies.