Essay 3- Congenital hemolytic anemias- microspherocytosis and enzymopathies
- What are hemolytic anemias?
- Decreased levels of red blood cells in circulating blood (anemia) because of their accelerated destruction (hemolysis)
- Classification of hemolytic anemias
- Hereditary (congenital)
- Membrane- hereditary spherocytosis, hereditary eliptocytosis
- Metabolism- G6PD deficiency, PK deficiency
- Hemoglobin- genetic abnormalities (HbS, HbC, unstable)
- Acquired
- Immune- warm and cold antibody types, hemolytic transfusion reactions, hemolytic disease of newborn
Types of hemolysis
- Intravascular (acute hemolytic transfusion reactions, severe burns, physical trauma, bacterial infections, etc)
- Extravascular (the physiological type, in the spleen, also in the liver)
- Infections- malaria, clostridia
- Chemicals- drugs, burns
- Secondary- liver and renal disease
Classification of haemolytic anemia- hereditary
Extravascular Hemolysis
Defects of the red cell membrane
- Hereditary spherocytosis, microspherocytosis (Minkovski-Shauffard)
- Hereditary elliptocytosis
- Hereditary stomatocytosis
- Hereditary abetalipoproteinemia...etc
Defective red cell metabolism (intraerythrocytic enzyme deficiency)
- G6PD deficiency
- PK deficiency
Defects of hemoglobin synthesis
- Thalassaemia
- Hemoglobinoses (Sickle cell anemia, etc)
Classification of haemolytic anemia - acquired
Intravascular Hemolysis
- Immune mediated:
- Autoimmune: cold agglutinines, warm agglutinines, biphase agglutinines of D&L
- isoimmune (ABO, RH)
- drug-mediated
- Microangiopathic: DIC, HUS, TTP
- Hypersplenism
- Miscellaneous; drugs, bio-toxin, infection, burn, chemicals, radiation,
Laboratory findings - extravascular hemolysis
- Anaemia
- Reticulocytosis
- Indirect hyperbilirubinemia (unconjugated)
- High LDH
- High serum Fe
- Elevated free Hb in serum (hemoglobinemia)
- Low haptoglobin (the transporting protein of Hb)
- Urobilinogenuria
Laboratory findings - intravascular hemolysis
All the tests for extravascular haemolysis plus:
- Hemoglobinemia
- Met-hemalbuminemia
- Hemoglobinuria
- Hemosiderinuria
G6PD, glucose-6-phosphate dehydrogenase; Hb, haemoglobin.