Iron Metabolism/Deficiencies

Question 1

About how much iron is in a normal man?

Answer 1

About 3500 mg

Question 2

If a man loses 1 ml of blood, how much iron does he lose?

Answer 2

1 mg

Question 3

What is the labile iron pool?

Answer 3

Iron leaving the plasma and entering the interstitial and intracellular fluid compartments (80-90 mg)

Question 4

How much iron is in transferrin?

Answer 4

3mg (smallest pool)

Question 5

What does transferrin do?

Answer 5

Carries protein in plasma

Question 6

How saturated is transferrin with iron?

Answer 6

About 1/3rd

Question 7

What is the turnover rate of transferrin and where is it synthesized?

Answer 7

10 times; liver

Question 8

What is the minimal daily iron requirement for an infant? child? young woman? pregnant woman? Man/postmenopausal woman?

Answer 8

1, .5, 2, 3, 1 (x10 for amount that should be ingested daily)

Question 9

What has the highest nutritional value of iron? Lowers?

Answer 9

Liver; Milk, noodles, rice

Question 10

What are the 4 factors influencing iron absorption?

Answer 10

1) Iron Stores
2) Rate of Erythropoiesis
3) Hypoxia
4) Inflammation

Question 11

What 2 things are involved in the regulation of iron uptake?

Answer 11

Ferriportin and Hepcidin

Question 12

What does ferriportin do?

Answer 12

It is the cellular exporter of iron into the plasma, it regulates the transfer of iron from mother to fetus, the iron absorption in intestines, and export from macrophages

Question 13

What does hepcidin do?

Answer 13

It is a negative regulator of iron uptake; it binds ferriportin and degrades it. This inhibits iron flow into plasma from recycled RBCs, inhibits duodenal enterocytes engaged in absorption, and inhibits hepatocytes that store iron

Question 14

What increases the absorption of non-heme iron?

Answer 14

Reducing agents (ascorbic, gastric acid)

Question 15

What decreases the absorption of non-heme iron?

Answer 15

Insoluble complexes, chelating agents

Question 16

What are factors outside the GI tract that increase iron absorption?

Answer 16

Hypoxia, Anemia, Depletion of stores, Increase erythropoesis

Question 17

Is dietary iron deficiency rare in the US?

Answer 17

Yes, in adults and more rare in men

Question 18

How can infants become iron deficient?

Answer 18

Milk is a poor source

Question 19

What are the 3 factors leading the the malabsorption of iron?

Answer 19

GI Tract Surgery, Non-tropical Sprue, Picca

Question 20

What is the GI surgery called used to fix malabsorption?

Answer 20

Billroth surgery

Question 21

What is non-tropical sprue ?

Answer 21

Cluten induces damage to differentiated villus epithelial cells of small intestine (found in rye, oats, and barley). The metabolites of gluten lead to an immunologic reaction and leads to severe malnutrition

Question 22

How do you treat non-tropical sprue?

Answer 22

Stop all grains except rice and corn, symptoms will be gone in days to weeks

Question 23

What is tropical sprue?

Answer 23

Cause is unknown but thought to be an overgrowth of coliforms in jejunum, leads to release of enterotoxin inducing fluid secretion which then leads to malabsorption of folic acid, cobalamin and fat

Question 24

How do you treat tropical sprue?

Answer 24

2 months of tetracycline and folix acid, B12 if that is deficient too

Question 25

What is Picca?

Answer 25

Eating laundry starch or clay (Clay is a chelator which binds iron)

Question 26

What are the 6 causes of GI tract bleeding in US?

Answer 26

1) Peptic Ulcer Disease 2) Hiatal Hernia 3) Chronic Gastritis 4) Hemorrhoids 5) Intermittent bleeding after GI surgery 6) Neoplasms of the GI tract

Question 27

What are the 2 causes of GI tract bleeding in infants?

Answer 27

1) Milk Allergy | 2) Meckels Diverticulum

Question 28

What are the 5 unusual causes of iron deficiency?

Answer 28

1) Respiratory tract bleeding 2) Intravascular hemolysis 3) Chronic renal dialysis 4) Blood donation 5) Factitious bleeding

Question 29

How much iron is lost in menstrual bleeding?

Answer 29

20-30 mg/month, x2 in 10% of women

Question 30

How much iron is lost during delivery?

Answer 30

150-200mg

Question 31

How much iron is lost during lactation?

Answer 31

30 mg/month

Question 32

Hookworm (Ancylostoma duodenale) is a cause of what?

Answer 32

Iron deficiency anaemia

Question 33

What are the symptoms of chlorosis?

Answer 33

Green palor, breathlessness, palpitations, slight ankle edema, GI complaints, emotional disturbance, depression, irritability, moody, "pervasion of appetite"

Question 34

What are the symptoms of Iron deficiency?

Answer 34

Asymptomatic at first, but then fatigue, headache and parathesias, irritability, decreased exercise tolerance, burning tongue, picca

Question 35

What are the physical findings of iron deficiency?

Answer 35

Pallor, glossitis, stomatitis, angular chelitis

Question 36

What is Koilonychia?

Answer 36

From iron deficiency, nails become concave, rigid, and brittle

Question 37

``` In a CBC tell whether the following values are low or high (patient with iron deficiency): WBC = 5000/microliters Hmt = 28% MCV = 78 fl RDW = 22% Platelets = 550,000/microliter Retic Count = .2% ```

Answer 37

Unaffected, low, low, elevated, elevated, very low

Question 38

In a bar graph showing the total-iron binding capacity, what is the bar split into?

Answer 38

2 Sections, 1 shows unsaturated capacity, the other shows plasma or serum iron

Question 39

What does increased erythropoetic activity and iron deficiency do to hepcidin?

Answer 39

It suppresses it so more ferriportin is available to increase dietary iron absorption and release iron from stores

Question 40

Chronic inflammation does what to hepcidin?

Answer 40

Releases cytokines that increase levels of hepcidin, degrades ferriportin which decreases GI uptake and decreased upake from storage

Question 41

What are the indications for parenternal iron therapy?

Answer 41

Malabsorption, intolerance to oral iron, uncooperative patient, inability to folow instructions

Question 42

What is Iron Dextran?

Answer 42

Given IM, slowly absorbed and peaks after 10 days; however is painful at site and stains skin

Question 43

What are benefits/disadvantages of IV iron delivery?

Answer 43

It replenishes iron stores in ours, but leads to thrombophlebitis, arthralgia and fever, hypotension and bradycardia, nasuea and vomiting, or anaphylactic reaction (death)

Question 44

What are the 5 things to ask if a patient does not respond to iron replacement?

Answer 44

1) Is diagnosis correct? 2) Has bleed been controlled? 3) Has patient been on iron long enough? 4) Has the dose been adequate? 5) Are there factors that would slow a response?

Question 45

What increases absorption of Iron (digestive)?

Answer 45

HCl, Ascorbic acid