10 anemia

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10 anemia

  1. 1. Anemia
  2. 2. Introduction • Not a single disease • Results from a number of different pathologies • Defined as a reduction from the normal quantity of Hb in blood • Who defines anemia as Hb levels less than 13 g/dl for males and less than 12 g/dl for females • Low Hb levels results in decreased oxygen carrying capacity of blood
  3. 3. Epidemiology • Most common condition resulting in significant morbidity and mortality • Worldwide: Over 50% of pregnant women and 40 % of infants are anemic
  4. 4. Aetiology Two different mechanisms: 1. Reduced Hb synthesis (due to lack of nutrient or bone marrow failure) Reduced proliferation of precursors or defective maturation of precursors or both
  5. 5. Aetiology (contd…) • Increased Hb loss due to haemorrhage (red cell loss) or hemolysis (red cell destruction) (More than one cause can be found in a patient)
  6. 6. Normal erythropoiesis Pluripotent stem cell Erythroid burst forming unit Erythroid colony forming unit Within BM Erythroblast Reticulocyte Mature red cell Peripheral blood
  7. 7. Normal erythropoiesis (contd…) • Erythropoietin production si impaired n condictions such as RA, cancer and Sickle cell anemia • Each day about 2 *1011 erythrocytes enter the circulation • Normally survive for 120 days
  8. 8. Normal erythropoiesis (contd…) • Destroyed by reticuloendothelial system found in spleen and BM • Iron is removed from haem component of Hb and transported back into bone marrow for reuse
  9. 9. Normal erythropoiesis (contd…) • Pyrole ring from globin is excreted as conjugated bilirubin by the liver and the polypeptide portion enters the body’s protein pool
  10. 10. Clinical manifestations • Mildest form: tiredness and lethargy, reduced mental performance • Non-specific signs and symptoms associated with anemia: Tiredness, Pallor, Fainting, Exertional dyspnea, Tachycardia, Palpitations, Worsening angina, Worsening cardiac failure, Exacerbation of intermittent claudication
  11. 11. Investigations • No place for blind treatment • Anemia is a consequence of reduced concentration of Hb in each red cell and/or reduced number of red cells in peripheral circulation • Imp parameter: Hb concentration of blood, including its size , shape and color, MCV to determine type of anemia • Bone marrow examination
  12. 12. Iron deficiency anemia • Epidemiology: 20% of world’s population • Cause: diet deficient in iron, parasitic infestations and multiple pregnancies • Aetiology: Blood loss, GI bleeding (most likely), Haemorrhoids, nosebleeds or postpartum haemorrhage
  13. 13. Iron deficiency anemia Causes of Iron deficiency anemia • Inadequate iron absorption Dietary deficiency Malabsorption • Increased physiological demand • Loss through bleeding
  14. 14. Pathophysiology • • • • Elimination not controlled physiologically Homeostasis maintained by controlling iron absorption Absorption inefficient Iron bound to haem is better absorbed than iron found in vegetables • Phosphates and phytates leads to formation of unabsorbable complex, while ascorbic acid increases iron absoprtiopn
  15. 15. Pathophysiology (contd…) • Anemia a result of mismatch between body’s iron requirement and iron absoprtion • Fortified milk given to children up to the age of 18 months increases Hb levels and improve performance • Iron malabsoprtion occurs in patients with coleliac disease and in 50% patients following gastrectomy
  16. 16. Pathophysiology (contd…) • During pregnancy: dilutional anemia • Some of the increased demand is met by stopping menstruation Whatever the cause might be inadequate iron absorption leads to anemia
  17. 17. Clinical manifestations • • • • • • • Pale skin and mucous membrane Painless glossitis Angular stomatitis Koilonychia Dysphagia Pica Atrophic gastritis
  18. 18. Investigations • Serum iron, Total iron binding capacity (TIBC) and serum ferritin • Aim: To correct anemia and replenish iron stores Important to resolve the underlying cause as far as possible
  19. 19. Treatment • Folic acid use during pregnancy • Prophylaxis in menorrhagia, after partial gastrectomy and in some low birth weight infants • Continue for 6 months to both correct anemia and replenish body stores • Standard treatment: 200 mg three times a day
  20. 20. Treatment (contd…) • It takes 1 to 2 weeks for Hb level to rise to 1 g/dl • N and abdominal pain occurs in some patients • Alternative salts of iron are tried • Absorption is 15% of intake during the first 2-3 weks but falls off to an average of 5% thereafter • Modified release oral preparations also available
  21. 21. Treatment (contd…) • There is little place for parenteral iron • In renal patients, a regular weeks dose is often given and patients’ serum ferritin monitored to check for iron overload
  22. 22. MEGALOBLASTIC ANEMIA • They are macrocytic anemia (raised MCV) • Abnormality in the maturation of haemopoietic cells in the bone marrow • Two causes: Folate deficiency and Vit. B12 deficiency anemia • Pernicious anemia is a specific disease caused by malabsorption of Vit B12
  23. 23. Aetiology Folate deficiency anemia • Readily available in normal diet (Fruit, green vegetables and yeast) • Folate deficiency either due to folic acid deficiency anemia or increased folate utilization
  24. 24. Aetiology (contd…) Vitamin B12 deficiency anemia • Inadequate intake or malabsorption (dueto removal of distal ileum) • Dietary source: Food of animal origin • Daily requirements: 1-2 micrograms
  25. 25. Pathophysiology • Common: inhibition of DNA synthesis in maturing cells
  26. 26. Folate deficiency anemia Dietary folate Gut Folate monoglutamate Methyltetrahydrofolate monoglutamate Tetrahydrofolate monoglutamate Bone Tetrahydrofolate polyglutamate marrow Folate co-enzymes Dihydrofolate Polyglutamate
  27. 27. Pathophysiology of Vit. B12 deficiency anemia • Absorption occurs by an active process • Enzyme in the stomach release Vit. B12 from protein complexes • One molecule of Vit. B12 combine with one molecule of glycoprotein (called intrinsic factor) • There are specific receptors in the distal ileum for intrinsic factor-Vit B12 complex • Vit B12 enters the ileal cell and is then transported through the blood attached to transport proteins • A total gastrectomy always leads to Vit. B12 deficiency • Onset of anemia is usually delayed
  28. 28. Pathophysiology of pernicious anemia • Autoimmune in origin • Patients typically have a gastric atrophy and no or virtually no intrinsic factor secretion • Two different intrinsic factor antibodies have been produced in serum of patients with pernicious anemia • Gastric parietal antibodies found (in 90% patients)
  29. 29. Clinical manifestations • • • • • • • • • • Glossitis Angular stomatitis Altered bowel habit Anorexia Mild jaundice Insiduous onset Sterility Bilateral peripheral neuropathy Melanin skin pigmentation Fever
  30. 30. Investigations Folic acid deficiency anemia • • • • Symptomless initially Large oval red cells Anisocytosis and poikilocytosis Thrombocytopenia
  31. 31. Investigations (contd…) Vit B12 deficiency anemia • Serum Vit B12 level • Serum folate level • Measuring absorption of Vit. B12 (by Schilling test) • Parietal cell antibodies (not accurately diagnostic)
  32. 32. Treatment • Necessary to establish whether the patient with megaloblastic anemia has Vit. B12 deficiency or folic acid deficiency or both
  33. 33. Treatment of folate deficiency anemia • Replacement therapy • Duration of treatment depends on cause • Changes in dietary habit or removal of any precipitating factor • Normal daily requirement approx. 100 micrograms per day • Dose: 5-15 mg per day for 4 months • Parenteral folic acid treatment not normally required
  34. 34. Treatment of folate deficiency anemia during pregnancy • Folate requirement increases in pregnancy and is higher in twin pregnancies • Prophylaxis with folate ( 350-500 micrograms) frequently given during pregnancy
  35. 35. Treatment of Vit. B12 deficiency anemia • Require life long replacement therapy • Transfusion not normally given • If emergency transfusion deemed necessary, packed cells may be given • Diuretics also given • Definite diagnosis should be made before starting treatment • Std. treatment: Hydroxocobalamin 1 mg IM repeated five times at 3 day intervals to replenish body stores, followed by maintenance dose, usually 1 mg IM every 3 months.
  36. 36. Sideroblastic anemias • Group of conditions diagnosed by finding ring siderobalst in the BM • Both hereditary and acquired forms present
  37. 37. Aetiology • In hereditary forms, there is X chromosome linked pattern of inheritance • Both autosomal dominant and autosomal recessive families present • Defect: Reduced activity of the enzyme 5aminolevulinate synthase (ALAS)
  38. 38. Pathophysiology • Examination of BM shows number of erythroblasts that have iron granules surrounding the cell nucleus (known ad ring sideroblast) • Low levels of ALAS in hereditary forms • Drugs and toxins: Alcohol, Isoniazid in slow acetylators, Dose of Chloramphenicol over 2 g
  39. 39. Clinical manifestations • • • • Develop on infancy or childhood Severe or mild anemia Splenomegaly Idiopathic forms tends to develop insiduously (middle age or later) • Many becoem asymptomatidc for long periods
  40. 40. Investigations • In heriditary fomrs: red cells in peripheral blood are hypochromic and microcytic • Increased iron stores in BM • Serum iron and ferritin high • In acquired forms: Peripheral blood has hypochromic cells which may be either normocytic or macrocytic • Common finding: Presence of sideroblast in BM
  41. 41. Treatment • For hereditary forms: 200 mg daily Pyridoxine • Frequent blood transfusion required in unresponsive patients • Desferrioxamine given i.v or s.c • Oral Vit. C
  42. 42. Hemolytic anemias • Reduced life span of erythrocytes • Imbalance between rate of destruction and rate of production • Presence of both genetic and acquired disorders
  43. 43. Aetiology of Sickle cell anemia • They have a different form of Hb (Hb S) • Patients with homozygous Hb S develop many problems including anemia • Sickle cell trait is usually asymptomatic • The offspring from a father with a trait and a mother with a trait has a 1 in 4 chance of having sickle cell disease •
  44. 44. Aetiology of Thalassaemias • No alpha chain production or reduced production of a chain • Heterozygotes are symptomless
  45. 45. Aetiology of G6PD deficiency • Large variants of G6PDdeficiency • It is an enzyme involved in the production of reduced glutathione
  46. 46. Pathophysiology of Sickle cell disease • Membrane of red cells containing Hb S is damaged (lead to IC dehydration) • Polymerization of Hb S occurs when the patients blood is deoxygenated • These two processes lead to crescent-shaped cells (known sickle cell)
  47. 47. Pathophysiology of Sickle cell disease (contd…) • Sickle cells are less flexible than normal cells • This leads to local tissue hypoxia • Anemia results from an increased red cell destruction
  48. 48. Pathophysiology of Thalassemia • Reduced or absent production of globin beta chain • Leads to relative excess of alpha chain, when unpaired become unstable and precipitate in red cell precursors • Ineffective erythropoiesis • In alpha thalassemia, deficiency of alpha chain leads to an excess of beta or gamma chains
  49. 49. Pathophysiology of Thalassemia (contd…) • Erythropoiesis is less affected but Hb produced is unstable when the cells are in circulation and precipitate as the cells grow older
  50. 50. Pathophysiology of G6PD deficiency • Essential for the production of reduced form of NADPF in RBC • NADPH is needed to keep gluthathione in reduced form • Glutathione helps RBC deal with oxidative stress • In G6PD deficiency Hb becomes oxidised and Heinz bodies are form
  51. 51. Clinical manifestations • Malaise • Fever Abdominal pain • Dark urine • Jaundice
  52. 52. Clinical manifestations of Sickle cell anemia • Chronic anemia, arthralgia, fatigue, splenomegaly. Crisis precipitated by infection, fever. Dehydration, hypoxia or acidosis. Severe pain is a common feature.
  53. 53. Clinical manifestations of thalassemia • Causes Erythropoietin production to increase andresulst in expansion of BM • Bone deformity and growth retardation • Spleen becomes enlarged
  54. 54. Clinical manifestations of G6PD deficiency • Two forms • This form is self-limiting
  55. 55. Treatment • Sickle cell anemia: prophylactic antibiotics (Penicillin V 250 mg b.d), pneumococcal vaccine, hydroxyurea is effective. • Thalassemia: transfusion, desferroxamine and deferiprone • G6PD deficiency: causative oxidising agent stopped and general supportive measures adopted. No specific drug treatment for this disorder

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