Iron Metabolism & Disorders

Question 1

Total body iron in the body

Answer 1

4g

Question 2

Distribution of iron in the body (in mg)

Answer 2

• 2500 mg in the RBCs
• 500 mg in macrophages
• 500 mg in liver
• 500 mg in muscle
• Total 4000mg = 4g
• 4mg iron circulates in the plasma (= 0.1% of total body iron)

(all the values are approximate)

Question 3

Distribution of iron in the body (in percentage)

Answer 3

• 70% = Haemoglobin (the majority)
• 25% = Ferritin and hemosiderin
• 4% = Myoglobin
• 0.1% = Plasma iron

Question 4

Site of absorption

Answer 4

upper small intestine

Question 5

Amount of absorption

Answer 5

About 10-15% of dietary iron is absorbed (regulated according to body’s need)

From intake of 6mg (per 1000Kcal) of dietary iron >>>> 15% is bioavailable

Question 6

Chemical form of iron absorption

Answer 6

Fe²⁺ form from the gut

Fe²⁺ (ferrous) (present in gut) >>>> much better absorbed >>>> than Fe3+ (ferric) (present in blood)

Question 7

Iron absorption is increased by-?

Answer 7

• Vitamin-C
• Gastric acid

Question 8

Iron absorption in reduced by-?

Answer 8

• PPIs (Reduced HCL)
• Gastric achlorhydria (NO HCL)
• Tannin (in tea)
• Tetracycline

Question 9

Transport of iron

Answer 9

From the gut >> Fe²⁺ enters the intestinal wall cell >>> In the intestinal wall, Fe²⁺ (ferrous) >> oxidation (by caeruloplasmin) >> Fe³⁺ (Ferric) >> enters blood >>> Fe³⁺ binds to transferrin >> transported throughout the body

Question 10

Storage of iron

Answer 10

• In tissues, as ‘Ferittin’

It is a plasma protein

It is an acute phase reactant >> increased in inflammations & post-surgery

Question 11

Excretion of iron

Answer 11

Iron (heme) of RBC >>> metabolised & re-utilised

Others >>> lost via intestinal tract (by intestinal wall desquamation) >>> 1mg/day is lost

Question 12

What is Ferritin?

Answer 12

A plasma protein

Question 13

What situations increase ferritin?

Answer 13

• Inflammation
• Infection
• Malignancy

Question 14

Anaemias with low MCV

Answer 14

• IDA
• Thalassemia
• Chronic haemolytic anaemia
• Sideroblastic anaemia
• Anaemia due to chronic disease
• Haemochromatosis
• Pregnancy

Question 15

Iron profile of IDA

Answer 15

• Serum iron: Low
• Serum ferritin: Low
• TIBC: High

Question 16

Iron profile of thalassaemia

Answer 16

• Serum iron: high
• Serum ferritin: high
• TIBC: Low

Question 17

Iron profile of chronic haemolysis

Answer 17

• Serum iron: high
• Serum ferritin: high
• TIBC: Low

Question 18

Iron profile of sideroblastic anaemia

Answer 18

• Serum iron: High
• Serum ferritin: High
• TIBC: Normal (Sometimes low)

Question 19

Iron profile of anaemia due to chronic diseases

Answer 19

• Serum iron: Low
• Serum ferritin: High
• TIBC: Low

Question 20

Iron profile of haemochromatosis

Answer 20

• Serum iron: High
• Serum Ferritin: High
• TIBC: Low

Question 21

Similarities of iron profile in thalassaemia, chronic haemolysis and haemachromatosis

Answer 21

• Serum iron: High
• Serum ferritin: High
• TIBC: Low

Question 22

Structure of transferrin

Answer 22

Glycoprotein (Glucose + Protein)

Question 23

Function of transferrin

Answer 23

carries ferric iron & helps in internal iron exchange

Question 24

Transferrin level is increased by-?

Answer 24

IDA

Pregnancy

COCP

Question 25

**Transferrin level is reduced by-?**

Answer 25

**Haemochromatosis**

Question 26

**How to calculate transferrin saturation in percentage?**

Answer 26

**(Plasma iron / TIBC) x 100**

Question 27

**Normal transferrin saturation**

Answer 27

**33%** **In absence of anaemia, 33% of transferrin remains saturated**

Question 28

**Use of transferrin saturation**

Answer 28

**to measure iron stores**

Question 29

**Transferrin saturation in iron deficiency**

Answer 29

**Below 16%**

Question 30

**Relation between iron and transferrin level**

Answer 30

**Inversely proprotional** **More iron \>\>\>\>\> Low transferrin level** **Less iron \>\>\>\>\> More transferrin level**

Question 31

**Relation between iron and transferrin saturation**

Answer 31

**Proportional** **More iron \>\>\>\>\> More transferrin** **Less iron \>\>\>\>\> Less transferrin**

Question 32

**Conditions with high transferrin level**

Answer 32

**Iron deficiency anaemia** **Pregnancy** **COCP**

Question 33

**Conditions with low transferrin level**

Answer 33

**Haemochromatosis**

Question 34

**Conditions with high transferrin saturation**

Answer 34

**Haemochromatosis**

Question 35

**Conditions with low transferrin saturation**

Answer 35

**Iron deficiency anaemia (below 16%)**

Question 36

**Findings in haemochromatosis**

Answer 36

**Mucosal cells \>\>\>\>\> high content + high iron saturation** **Blood \>\>\>\>\> Low transferrin level + High transferrin saturation**