K9 - Iron Deficiency Anemia

8/3/2019 K9 - Iron Deficiency Anemia

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IRON DEFICIENCY ANEMIA

Dr Zaimah Z Tala, MS, SpGK

Nutrition DeptFaculty of Medicine,

University of Sumatera Utara


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Definition

Deficit of circulating RBC associated with

diminished oxygen-carrying capacity of theblood

Most common hematologic disorder by far

Hb < 12 g/dL

Hb < 13 or 13.5 g/dL


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classification

Microcytic (small cell)

- Major nutritional cause is iron deficiency

- Minor pirydoxin & copper deficiency Normocytic anemia

- PEM & various chronic disease

Macrocytic- Vit B12 & folic acid deficiency


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Iron-deficiency anemia is the most common

nutritional anemia and perhaps

the most common nutritional deficiency

disorder in the world.


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Characterized by the production of small

erythrocytes and diminished level of

circulating hemoglobin

Last stage of iron deficiency

Represent the end point of a long period of

iron deprivation


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The greatest risk :

- between 6 mo 4 yrs

- early adolescent- during the menstruating years

- during pregnancy


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Causes of Iron Deficiency

Dietary inadequacy the most common cause- poor diet (vegetarian)

Inadequate absorption Diarrhea ; intestinal disease ; atrophic gastritis ;

Achlorhydria ; partial or total gastrectomy ; drug interference Increased Iron requirement

Pregnancy Infancy Adolescence lactation

Increased excretion- excessive menstrual blood- hemorrhage from injury- chronic blood loss


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Pathophysiology

Iron in the body :

- functional form : heme, myoglobin,part of many enzyme

- storage : ferritin & hemosiderine


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Dietary Iron

Heme Fe (meat, fish and poultry) best

absorbed.

Non-heme Fe (cereal, vegetables) taken up lessavidly.

Heme Fe 20% bioavailable, nonheme only 3%

Ionic Fe (Fe++) also well absorbed.

>1/3 of Fe from fortification of flour.

Tea inhibits Fe absorption.


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Iron Absorption

Proximal small bowel, esp duodenum

Enhanced by gastric acid (Fe+2 is valance

absorbed) Heme Fe > non-heme Fe

Reciprocal relationship to iron stores

Direct relationship to erythropoiesis; with

ineffective erythropoiesis Inhibited by inflammation, phytates


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Plasma

Fe

16%

65%

4%

15%


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The great majority of iron in the body is found in red cells

where it is incorporated into hemoglobin to function as an

oxygen carrier. Smaller amounts are incorporated intomyoglobin (muscle) and cytochromes (all tissues). As red cells

turnover in the spleen, iron is recycled back to the bone

marrow where it is re-incorporated into hemoglobin. Iron is

transported through the plasma bound to transferrin and taken

up by cells via the transferrin receptor. Iron is concentrated andstored within the cell encased by ferritin. Excess iron is stored

primarily in the macrophages of the liver, spleen and bone

marrow Very little iron is lost except through bleeding and

menstruation. Therefore, homeostasis of total body iron ismaintained by regulating intestinal iron absorption.


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IRONBody Compartments - 75 kg man

Stores1000mg

Tissue500 mg

Red Cells2300 mg

30 mgAbsorption < 1 mg/day

Excretion < 1 mg/day


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IRON STORESIron Deficiency Anemia

Stores0 mg

Tissue500 mg

Red Cells1500 mg

3 mg

Absorption 2-10 mg/day

Excretion Dependent on Cause


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Mechanisms for maintaining iron balance :

- continuous reutilization of iron

- regulation of the absorption of iron

- access to specific storage protein (ferritin)


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Progression of Findings

Bone Marrow iron

Serum Iron drops Total Iron Binding Capacity Increases

MCV & Hb

Blood Smear - Microcytic, Hypochromic


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Typical diet; formerly ~10-15 mg/d,

now ~24 mg/d

10-15% comes from heme sources (meats &

seafood)

85-90% comes from non heme sources (dried

beans, peas, leafy green vegetable)

>1/3 of Fe from fortification of flour.


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Iron-deficiency anemia is usually discoveredduring a medical examination through aroutine blood test. In addition to a complete

medical history and physical exam, diagnosticprocedures for iron-deficiency anemia mayinclude additional blood tests and other

evaluation procedures.

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Symptoms

Fatigue - Sometimes out of proportion to

anemia

Atrophic glossitis

Pica, esp chew ice

Koilonychia (Nail spooning)


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Clinical Presentation

Asymptomatic

Pallor

fatigue, tachycardia

Blue sclera

Koilonychia


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Lab Findings

Plasma ferritinmeasure of iron stores

Transferrin saturation

< 16% inadeq for eryhtropoiesis

Ratio erythrocyte protoporphyrin to heme

sensitive indicator of the iron supply to the

developing RBC

Hb or Ht


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Hb concentration is unsuitable as a diagnostic

tool of IDA, because :

- it is affected only late in the disease

- it does not indicate the type of anemia thatexist

- there is a wide variation in values in normal

subjects


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Anemia: Lab Evaluation

Normal Periperhal Smear Iron Deficiency Anemia


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IRON DEFICIENCY

Serum Iron Transferrin Ferritin

Iron Deficiency


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Medical Management

Treatment should focus on the underlying

disease, although this is often difficult

Repletion of iron stores, not merely alleviation

of the anemia should be the goal


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Therapy

Oral ferrous form

- ferrous sulfate most widely used

- 50 - 200 mg elemental Fe/d (60 mg,

1-3 x / d

- 6.0 mg elemental Fe/kg per day in children

- Duration- 6 months

Parenteral-Fe dextran 50 mg/ml, 100 mg/d im/iv

- more expensive & not as safe


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IRON THERAPY

Response

Initial response takes 7-14 days

Modest reticulocytosis (7-10%) Correction of anemia requires 2-3 months

6 months of therapy beyond correction of anemia

needed to replete stores, assuming no further loss ofblood/iron

Parenteral iron possible, but problematic


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If supplementation fails, maybe that :

1. The patients may not be taking themedication, most likely because ofunpleasant side effect

2. Bleeding may be continuing3. The supplemental iron is not being absorbed

parenteral route


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Medical nutrition therapy

In addition to supplementation, attention

should be given to the amount of absorbable

dietary iron

Liver, kidney, beef, egg yolk, dried fruit, dried

peas and beans, nuts, green leafy vegetables,

whole grain breads and cereals, and fortifiedfood.


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Factorsaffecting absorption

Enhancing factors :

- ascorbic acid

- MFP

Inhibiting factors :

- carbonates

- oxalates

- phytates

- tanin


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Prevention

Iron supplementation, i.e. giving iron tablets

to certain target groups Iron fortification of certain foods

Education about food in order to improve the

absorption


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Recommendations :

Improve food choices to increase amount of total

dietary iron

Include a source of vitamine C at every meal Include MFP at every meal if possible

Avoid drinking a large amounts of tea or coffee

with meals


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Confusing Chart

Documents

K9 - Iron Deficiency Anemia