IRON IN HEALTH AND DISEASE

Enterocyte Gut ABSORPTION OF IRON Fe+++ Ferritin Fe++ Tf-Fe+++ Fe++ Haem Tf

METABOLISM When iron is needed by the body, Ferritin gives up its iron to the blood stream. Fe+++ iron is reduced within the mucosal cell to Fe++ form and released. The apoferritin in the mucosal cell can then combine with dietary iron absorbed in the intestine. If all the mucosal cells are saturated, no further absorption.

METABOLISM Most of iron in blood stream is utilized by bone marrow to synthesize Hb. Some is used by other tissue in the formation of enzyme

BODY IRON CYCLING

FACTORS AFFECTING IRON ABSORPTION

Absorption Heme iron is better absorbed than non heme iron During states of iron balance, about 10% of dietary iron is absorbed Figure can increase by 2 or 3 times, during periods of iron deficiency

Factors affecting Iron Absorption Absorbed through intestinal mucosa, only when needed No excessive storage. Ferrous (Fe++) is better absorbed than Fe+++ (Ferric) Better absorbed in Acidic medium, by virtue of conversion of ferric to ferrous state.

Factors Absorption is more efficient in presence of Vit C, sulfhydral and other reducing substances Vitamin C and fructose forms soluble complexes with iron and therefore better absorbed.

High fiber in diet – decrease iron absorption Tea can also inhibit the absorption of non heme iron Phosphate, Oxalates, Phytates forms insoluble complexes with iron, preventing absorption.

Absorption Absorption increase with need: Period of rapid growth (in infancy) Childhood and adolescence During pregnancy, As a result of blood loss and At high attitude.

IRON DEFICIENCY Hypochromic Microcytic anemia: No of RBCs are either normal or reduced Amount of circulating Hb is reduced In each RBC the Hb. content fall Hb low, oxygen carrying capacity is reduced

IRON REQUIREMENTS Due to efficient conservation and reutilization in the body daily physiologic requirement is small. Healthy man loses about 1 mg/day iron, while women lose about 1.5 mg/day 10% of average available dietary iron is absorbed which comes to 10 mg/day required for men and 18 mg/day required for women

IRON REQUIREMENTS Pregnancy increase iron daily need by 3.5 mg/day To be taken as iron supplement and not diet 30 – 60 mg/day Lactation iron losses are 0.5 – 1.0 mg/day Continuous Supplementation needed for 2 – 3 month after delivery

IRON DEFICIENCY Commonest cause of anaemia worldwide Cause of chronic ill health May indicate the presence of important underlying disease eg. blood loss from tumour

CLINICAL FEATURES (Symptoms) Dizziness Headache Weakness Fatigue

CLINICAL FEATURES (signs) Pallor glossitis angular cheilosis and koilonychia. Koilonychia Glossitis

CLINICAL FEATURES OF IRON DEFICIENCY Angular Cheilosis or Stomatitis                                         

Hypochromic microcytic red cells

Iron deficiency develops Poor diet Chronic blood loss or both Intestinal parasite Bleeding Hemorrhoids Peptic Ulcer Heavy menstrual losses Closed space pregnancy Insufficient proteins Insufficient calories B – vitamins. / Ascorbic acid

Common situation where Iron Intake is inadequate. During infancy: Low iron content of milk Fe stores at birth which are usually sufficient only for first 6 months. During rapid growth in child hood and adolescences: Because of the need of expanding iron stores.

Common situation where Iron Intake is inadequate. During reproductive period: Menstrual losses During pregnancy, because of increased: Maternal blood volume Demands of the fetus and placenta Blood losses during child birth.

Iron overload Total amount of Fe in body can be increased by Excessive intake. Taking care of Abnormalities in iron absorption. Parenteral administration of iron. Overload iron by food alone  very difficult because of intestinal mucosal absorption.

Deposition of iron in the parenchymal cells of the liver. Toxic intakes of iron reported in children and adults ingesting medicine iron supplements. Lethal dose for Young Child = 3 grams Adult = 200 – 250 mg/kg BW. Overload can also be caused by defect in intestinal mucosa. (Hemochromatosis) Deposition of iron in the parenchymal cells of the liver.

BONE MARROW FILM STAINED FOR HAEMOSIDERIN

Advance stage Graying pigmentation of skin Poor liver function Liver enlargement and scaring Pancreatic infiltration and resultant diabetes. Myocardial disease resulting in Heart failure.

Things you need to know about Laboratory Testing for Iron Status Serum ferritin most useful test Low serum ferritin , a proof that patient is iron deficient Normal serum ferritin does not always rule out iron deficiency Certain conditions raise ferritin for reasons unrelated to iron status

DIFFERENTIAL DIAGNOSIS: IRON DEFICIENCY ANAEMIA

LABORATORY DIAGNOSIS Elevated % transferrin saturation Increased serum ferritin Genetic testing for mutations of HFE gene Evidence parenchymal iron overload on liver biopsy Amount of iron removed by venesection

WHEN DOES IRON BECOME A PROBLEM? Normally 3-5 grams of iron in the body. Tissue damage when total body iron is 7 – 15 g Total body iron is also increased to variable ammounts at baseline by the ineffective hematopoiesis of MDS which leads to suppressed hepcidin: which leads to excessive intestinal absorption of iron and recycling of catabolic iron from the RES cells 37