Source of Iron:
Exogenous source:
legumes(peas,beans,nuts, Dried fruits,Iron fortified food,Red wine, food rich in Vit-C
Endogenous source:
Normally body iron loss from desquamated surface cell add upto 1 mg daily.
Daily requirement of Iron:
Male- 0.5-1.0mg
Female
Menstruating –1.5-2.0mg
Pregnant – 1.5-2.5mg
Daily loss:
Loss in urine, sweat.
Male-0.5-1.0mg
Female – 1-2 mg
Distribution of iron in body:
Hb--------- 2.3g
Storage(available) tissue iron -----1.0g
(Ferritin and haemosiderin)
Essential (Non available) tissue iron----0.5g
(Myoglobin and enzymes of cellular respiration)
Plasma iron---------3-4mg
Blood iron:
Richest in iron.
1ml of blood contain 0.5 mg of iron.
Normal serum iron level is 11-30micromole/litre.
Fe remain in blood into 2 forms
In the Hb of RBC
By binding with transferrin.
Haemoglobin iron:
Constitutes approx. 60-70 percent of the total body iron, the absolute amount varying from 1.5-3.0 g.
At the end of their lifespan ,aged red cells are phagocytosed by cells of the reticulo-endothelial system.
Transferrin:
It is a plasma iron binding protein that is synthesized in liver.
Total plasma transferrin is about 8gm.
The function of TF is to transport of iron from-
Absorptive site to storage site
Storage site to bone marrow for erythropoesis
On storage site to other
Fe for erythropoesis comes mainly from transferrin. TF bound iron becomes attached by specifiq receptors to erythroblasts and reticulocytes in the marrow and the iron is removed.
Storage form of Iron in tissue:
Iron is stored as ferritin and haemosiderin in the following organs:
-Reticuloendothelial cells
-Liver cells
-Skeletal muscle cells
-Plasma
-Some in myoglobin and enzymes
Ferritin:
Comprises 2/3rd of total storage iron.
Water soluble
Early mobilized for Hb formation
Present small amount in plasma.
Haemosiderin:
Insoluble iron protein complex
Found in tissue as macrophages in Bonemarrow, Liver and spleen.
Iron absorption:
Normally approximately 1-2 mg of iron is absorbed.
site of absorption: duodenum and jejunum.
Iron is absorbed in ferrous form. Food iron remain in ferric form.
Mechanism of absorption:
Iron is absorbed from the intestine by the action of active transport or pinocytosis.
Both ferritin and transferritin are present in the absorptive cells of the intestinal mucosa and are believe together to regulate iron absorption.
When body iron is high-The ferritin contain of mucosal epithelium is also high and transferrin content is low and vice versa.
Symptom:
Iron that enter mucosal cell is trapped in ferritin and lost when mucosal cells is sloughed into the intestinal lumen
In iron deficiency anaemia the mucosal cell content of apoferritin is deminished and transferrin content is increased, thus iron absorption is accelerated.
Each day 1-2 mg of iron is lost from the body.
Most of the loss is due to minute quantities of iron present in epithelial cells and RBC in urine and faces.
With each menstrual cycle young women lost 40-80ml of blood which is equivalent to 20-40 mg of iron.
600-900mg of iron is lost as a consequence of each pregnancy.
Factors influencing iron absorption:
1.Ferrus state of iron is absorbed well than ferric.
2.Gastric acidity helps to keep iron in the ferrus state and thus increase absorption.
3.Stores: Iron absorption is increase with low iron stores and decreased in iron overload.
4.Increased erythropoetic activity, bleeding, haemolysis, high altitude increased absorption.
5.Haem iron is better absorbed than non-haem iron.
6.Reducing agents eg, vit C increased Fe absorption.
7.Alcohol increased absorption.
8.Formation of insoluble complex with phytate, or phosphate decrease iron absorption.
9.Increased absorption of iron in idopathic haemochromatosis.
Epidemiology:
About 20% of the worlds population is iron defficient and iron deficiency anaemia is the most common type of anaemia in clinical practise.
Occur all ages but common in child bearing ages
This is always secondary to an underlying disorder.
In industrialized communities-
due to chronic infection and often occult blood loss.
In third world country-
Poor intake of iron and defective absorbtion.
Clinical features of iron deficiency anaemia:
Fatigue
Faintness
Palpitation
Breathlessness
Headache
Angina of efforts
Sign:
Pallor of skin,
conjunctiva,
Mucous mb,
Nail bed.
Brittle nail
Spoon shaped nails (koilonychia
dysphagia andglossitis.
(plummer-vision syndrom)
Investigation of iron defiency anaemia
Blood and Bone marrow examination:
In blood:
Hb% reduced
RBC count-reduced
Total count of WBC-Normal
PCV-reduced
MCV- Reduced
MCH-Reduced
MCHC-Reduced
ESR- Slightly raised.
In Peripheral blood film:
RBC- Microcytic hypocromic
Anisocytosis and poikilocytosis present.
(Eliptical form are common, Elongated pencil shape cells are present, Target cells are small in number,Reticulocytes are normal or reduced in number.)
Total count of WBC- Normal
Platelates- Normal
Bone marrow examination:
1.Hypercellular marrow (Erythroid hyperplasia)
2.M:E ratio- Decreased
3.Erythropoesis- micronormoblastic
4.Granulopoesis- Normal
5.Megakaryopoesis-Normal
Biochemical findings:
1.serum iron falls (2.5-10 mm/l)
2.Serum ferritin -Reduced or normal (<12mg/l)
3.Total iron binding capacity- Increased (upto 100 mm/l)
4.Percentage saturation of iron binding protein-Decreased (<16%)
5.Normal serum concentration (20-40mg/dl).
6.Red cell protoporphyrin in increased to values ranging from (100-600 mg/dl)
