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Iron - Part 2 Practical Aspects

Iron - Part 2 Practical Aspects. Iron deficiency Hereditary hemochromatosis. 1. What is your approach to the history and physical examination?. Anemia . Check MCV. MCV 80 - 100 Normocytic anemia. MCV > 100 Macrocytic anemia. MCV < 80 Microcytic anemia. Defective synthesis of:. Fe.

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Iron - Part 2 Practical Aspects

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  1. Iron - Part 2Practical Aspects Iron deficiency Hereditary hemochromatosis

  2. 1. What is your approach to the history and physical examination?

  3. Anemia Check MCV MCV 80 - 100 Normocytic anemia MCV > 100 Macrocytic anemia MCV < 80 Microcytic anemia Defective synthesis of: Fe Globin chains thalassemias HbE Heme iron deficiency anemia anemia of chronic disease sideroblastic anemia lead poisoning

  4. Case 1 Question 1: discussion • iron deficiency most likely • symptoms suspicious for lower GI tract pathology. • ask about melena, hematochezia, weight loss, family history of colon ca • still ask about chronic inflammatory diseases • rectal exam indicated

  5. 2. What other investigations are appropriate? • serum ferritin 12 ug/L (30-400) • iron 8 umol/L (10-28) • TIBC 80 umol/L (38-76) • transferrin sat. 10 % (20-55) • Conclusion: Iron deficiency anemia

  6. Look for the cause • could consider stool for occult blood • but if negative, would you be reassured? • investigate the lower GI tract: colonoscopy

  7. 3. How would you replace iron? • oral is best • aim for 200 mg elemental iron/day, of which only 5-20% is absorbed in the iron-deficient state • 1 mg elemental iron ≠ 1 mg ferrous salts • avoid enteric coated iron preparations • adverse effects • GI • iron overload

  8. 4. How long would you treat for? • Continue until iron stores are replete (ie. ferritin well into normal range) • Usually 4 to 6 months, assuming no ongoing excessive iron losses. • Must follow patients on iron therapy • assess the adequacy of therapy • avoid iatrogenic iron overload • This may occur simultaneously with the management of the underlying cause

  9. 5. What is the expected response? • reticulocytosis within 5 to 10 days • anemia halfway corrected by 3 weeks* • hemoglobin corrected within 2 months* • ferritin will correct after the anemia has resolved *assuming cause of iron deficiency has been corrected

  10. Causes of failure of oral iron replacement • poor compliance • poor absorption of oral iron • ongoing negative iron balance • wrong diagnosis, or co-existing 2nd cause of anemia is present

  11. 6. What if the patient is intolerant to oral iron? • Iron dextran (IM) • risk of anaphylaxis (0.5 – 1%) • skin tattoo • Iron sucrose or gluconate (IV)

  12. Classic hereditary hemochromatosis • autosomal recessive • usually caused by homozygosity of C282Y mutation of HFE gene • prevalent • cellular mechanism still fuzzy • C282Y impairs HFE interaction with transferrin receptor (TfR1) • increases shift of iron into plasma from enterocytes

  13. Endorgan damage due to iron deposition in hereditary hemochromatosis • liver • cirrhosis • endocrine glands (pancreas, pituitary) • diabetes • hypogonadism (impotence, amennorhea) • heart • cardiomyopathy • joints • arthropathy • skin • bronze pigmentation Classic triad (cirrhosis, diabetes, bronze skin) now rarely seen

  14. Symptoms • asymptomatic • fatigue • symptoms relating to endorgan damage

  15. Tests for hemochromatosis

  16. Limited penetrance of homozygosity for C282Y abnormal liver, glucose, endocrine, cardiac tests organ damage high tissue iron high plasma iron mutant HFE

  17. Management • lifelong phlebotomy program • keep ferritin < 50 ug/L • genetic counselling • dietary counselling • avoid/minimize EtOH • avoid iron, megadose vitamin C • treat complications, if present • surveillance for new complications

  18. Prognosis • Phlebotomy initiated early (before endorgan damage) is compatible with normal survival • Established endorgan damage usually permanent, but progression can be slowed

  19. Iron - Part 2Practical Aspects Iron deficiency Hereditary hemochromatosis

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