1. Hemolytic Anemia Dr. Ahmed M. Rashad, MD Family Medicine PGY-1
2. Objective To know the different causes of hemolytic anemia To know its basic features To discuss two types namely: a.G6PD deficiency b.Autoimmune Hemolytic anemia (AIHA) 3. Introduction Hemolysis is the destruction or removal of red blood cells from the circulation before their normal life span of 120 days. 4. Causes 5. Basic features Abnormal and accelerated destruction of red cells. Increased breakdown of hemoglobin, which may result in: a) Hyperbilirubinemia b) Increased fecal and urinary urobilinogen Bone marrow compensatory reaction: a) Reticulocytosis, and slight macrocytosis in peripheral blood b) Expansion of bone marrow in infants and children with severe chronic hemolysis 6. G6PD deficiency 7. Introduction Glucose-6-phosphate dehydrogenase deficiency, the most common enzyme deficiency worldwide. 8. Figure: Worldwide prevalence of G6PD deficiency according to the World Health Organization. Peters A L , and Noorden C J V J Histochem Cytochem 2009;57:1003-1011 Copyright by The Histochemical Society 9. Pathophysiology X-linked recessive Characterized by abnormally low levels of glucose- 6-phosphate dehydrogenase The deficient metabolic enzyme is involved in the pentose phosphate pathway, especially important in red blood cell metabolism. 10. The WHO classifies G6PD genetic variants into five classes 11. Clinical Presentation 12. Asymptomatic. Prolonged neonatal jaundice, often requiring exchange transfusion. A history of infection or drug-induced hemolysis, or hemolysis following ingestion of fava beans. Gallstones may be a prominent feature. Splenomegaly may be present. 13. Diagnosis The diagnosis is generally suspected when patients from certain ethnic groups develop anemia after challenges from any of the above causes. Heinz bodies can be seen in red blood cells on a blood film. Rapid fluorescent spot test detecting the generation of NADPH from NADP. The test is positive if the blood spot fails to fluoresce under ultraviolet light. 14. Management The main treatment for G6PD deficiency is avoidance of oxidative stressors. Rarely, anemia may be severe enough to warrant a blood transfusion. Splenectomy generally is not recommended 15. Auto-immune Hemolytic Anemia (AIHA) 16. Definition Autoimmune hemolytic anemia (AIHA) is caused by autoantibody-induced hemolysis; usually idiopathic. It is most common among adults over age 50, in whom the diseases are usually chronic and relapsing. 17. Types 18. Warm AIHA Warm autoantibody IgG induce phagocytosis at 37C. Primarily leads to extravascular hemolysis Fc portion of antibody binds to macro-phages Spherocytes become trapped in spleen and are destroyed 19. Cold Agglutinin Disease The IgM autoantibody has an affinity for RBCs at cold temperatures (0C-18C) Idiopathic form of disease is frequently recurrent condition and often responds to cold avoidance; exacerbations are intermittent Critical to explore diagnosis of B-cell lymphoma, which will determine therapy Corticosteroids are usually not helpful 20. Causes 21. Paroxysmal Cold Hemoglobinuria A polyclonal IgG anti-P autoantibody binds to red blood cell surface antigens in the cold. When the blood returns to the warmer central circulation, the red blood cells are lysed with complement, causing intravascular hemolysis. Most often appears post-viral in children and young adults Viral infections that can cause PCH include measles, mumps, influenza. Bacterial infections that can cause PCH include syphilis. 22. Diagnosis Diagnosis is made by first ruling out other causes of hemolytic anemia The diagnosis of AIHA must meet two criteria: 1.evidence of hemolysis (anemia plus elevated reticulocyte count in the absence of blood loss); and 2.evidence of RBC autoantibodies/complement (usually indicated by a positive direct Coombs test). 23. Direct and Indirect Coombs Tests 24. Management Efficacy of treatment depends on the correct diagnosis of either warm or cold type AIHA. Warm type AIHA is usually a more insidious disease, not treatable by simply removing the underlying cause. First line therapy for this is usually with corticosteroids. Cold agglutinin disease is treated by avoiding the cold or sometimes with rituximab. 25. References WHO Working Group. Glucose-6-phosphate dehydrogenase deficiency. Bull World Health Organ. 1989;67:60111. Glucose 6 phosphate dehydrogenase deficiency. Accessed July 20, 2005, at:http://www.malariasite.com/malaria/g6pd.htm. Mason PJ. 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