Anemia Pathologies Overview

Anemia Pathologies

• Anemia is a reduction in the total circulating red blood cell mass.
• Acute blood loss leads to a loss of intravascular volume.
• Chronic blood loss results in a shortened red blood cell lifespan.
• Hemolytic anemias are characterized by a shortened red blood cell lifespan.
• Hereditary spherocytosis involves defects in the red blood cell (RBC) membrane.
• Glucose-6-Phosphate Dehydrogenase Deficiency results in deficient or impaired enzyme function, reducing RBC's ability to protect themselves against oxidative injury.
• Sickle Cell Disease is caused by deoxygenated hemoglobin, leading to red blood cell distortion and vascular occlusion.

Other Anemias

• Thalassemia is caused by a defect in globin synthesis, decreasing red blood cell production and lifespan.
• Thalassemia trait also involves a defect in globin synthesis, decreasing red blood cell production and lifespan.
• Hemoglobin H leads to moderate to severe anemia.
• Hydrops Fetalis is the most severe form of alpha-thalassemia. It often presents in children following infections like measles, mumps, CMV, EBV, and varicella.
• Paroxysmal Cold Hemoglobinuria involves hemolysis due to RBC membrane defects, increased susceptibility to complement-mediated lysis.
• Immunohemolytic anemia is caused by antibodies bound to RBCs, leading to their destruction.

Other Blood Disorders

• Pernicious anemia (Aplastic anemia) is a megaloblastic anemia.
• Pernicious anemia (Aplastic anemia) is characterized by pancytopenia, where red cell progenitors are completely absent or suppressed from the bone marrow.
• Pure Red Cell Aplasia is characterized by the complete absence of red cell progenitors from the bone marrow.
• Polycythemia Vera is a myeloproliferative disorder.

Causes and Effects of Red Blood Cell Disorders

• Blood loss, hemolysis, hereditary, immunohemolytic causes a reduction in the oxygen-carrying capacity of blood.
• Internal or external bleeding can lead to decreased blood pressure, and potentially cardiovascular collapse, shock, and/or death.
• Rate of blood loss exceeding production results in iron deficiency.
• Destruction of red blood cells can cause intravascular hemolysis.
• Inherited disorders, like Parovirus infection can lead to a decreased lifespan of affected RBCs, ranging from 10 to 20 days compared to a normal 100-120 days. They often result in moderate splenomegaly.
• Abnormalities in the hexose monophosphate shunt or glutathione metabolism cause intravascular and extravascular hemolysis, increasing susceptibility to complement-mediated lysis.
• Point mutations/defects in globin genes can cause hemoglobin defects, natural protections against malaria, and chronic hemolysis or splenomegaly.

Diagnostic Tests

• RBC count, Hgb, Hct, RBC indices: are used to diagnose red blood cell disorders.
• Hemoglobin electrophoresis: measures the different forms of hemoglobin.
• Direct Coombs test: assesses antibodies bound to RBCs.
• Urinalysis: aids in evaluating red blood cell conditions.

Treatments

• Blood transfusion: is used to replace lost blood.
• Iron supplementation: helps address issues with iron deficiency.
• Splenectomy: removal of the spleen
• Intrauterine transfusion: used in cases of severe fetal disease.
• Hematopoietic stem cell transplantation: a treatment option for certain conditions.
• Therapeutic phlebotomy: used to remove excess blood.

Additional Notes

• Inherited deletions of alpha-globin chains can lead to inadequate hemoglobin production.
• Severity of alpha-thalassemia often depends on the number of genes affected.
• Mutations in the phosphatidylinositol glycan group A gene (PIGA) can cause X-linked genetic defects.
• Specific laboratory tests, such as hemoglobin electrophoresis or direct Coombs tests, can offer further diagnostic insights into different types of anemia.
• Certain conditions, like Vitamin B12 deficiency, can affect RBC production, potentially resulting in anemia.
• The presence of warm or cold antibodies in the blood can lead to red blood cell destruction.
• Red blood cell abnormalities, such as microcytosis or hypochromia, may be apparent in blood smears in certain conditions.
• Pathologies associated with RBCs can be prevalent in specific populations.