2 Lesson 2 - Iron Deficiency Anemia

Lu Ji Zhou

Prevalence  Iron deficiency is the most common cause

of anemia throughout the world and one of the most common medical problems that confront the general physician.  Geographic distribution  Its prevalence is much higher in women

than in men.

Metabolism of Iron Iron  Functional iron  Storage iron

Table: Distribution of iron in the adult Type of Iron

Concentration men

Women

Functional iron heamoglobin

67%

31

28

myoglobin

15%

5

4

1

1

<1(0.2)

<1(0.2)

1000mg

300-400mg

Ferritin

8

4

Hemosiderin

4

2

50

40

Heme enzyme non-heme enzyme Transferrin iron Transferrin Storage Iron

Total

Iron Metabolism 1.Absorption 2.Transportation 3.Distribution(in the table ) 4.Excretion

Abso rpti on 1 、 The source of iron  iron in food ,diet . 2 、 The normal diet contains approximately 15 to 30 mg of iron each day, 1mg per day was absorbed by the intestinal mucous. 3 、 The place of absorption of iron  duodenum and the upper jejunum 4 、 Factors affect the absorption

Factors influencing the iron absorption

Excretion Quantity: 1mg / day pathway: skin, urine, bile and stool.

Definition  Iron deficiency is the state in which

the content of iron in the body is less than normal, this state is divided into 3 stages( or phases), as the following:



Iron depletion （ ID ） : this is the earliest stage of iron deficiency , in which storage iron is decreased or absent but serum iron concentration and hemoglobin levels are normal.

  Iron deficiency without anemia / iron deficient

erythropoiesis (IDE): this is a somewhat more advanced stage of iron deficiency, characterized by decreased or absent storage iron, usually low serum iron concentration and tranferrin saturation , without frank anemia. 

Iron deficiency anemia(IDA): this is the most advanced stage of iron deficiency. It is characterized by decreases or absent iron stores , low serum iron

Etiology 1. Increases demand for iron and inadequate iron intake, for examples: During the rapid growth spurts of infancy and adolescence . a. If the pregnant woman have iron-deficiency, although they are rarely anemic, do have low iron stores. These infants lack the reserves needed for the swift growth which occurs after birth. Iron deficiency during childhood has a number of deleterious consequences, such as impaired cognition.

b. During adolescent period, if the foods have low iron content and the need for iron is increased, the young people may encounter the iron deficiency anemia. c. There is another condition may lead to the need for iron increasing, that is hookworm infection, it make the added burden of blood loss.

2.   Decreased absorption of iron:  Partial or total gastrectomy  Chronic diarrhea or intestinal malabsorption.  Loss of hydrochloric acid

3.   Iron loss (1)   Physical iron loss eg. Menstruation and pregnancy (2)     Pathologic iron loss a.   Gastrointestinal tract disorders b.   infestation eg. hookworm c. Other Parasitic conditions eg.

Clinical features Patients

with

iron

deficiency

may

present  with no signs or symptoms , coming to

medical

attention

only

because

of

abnormalities on laboratory tests;  with

the

features

of

the

underlying

disorder responsible for the development of iron deficiency; 

1.   General manifestations , such as: (1)      Decreased work tolerance, weakness (2)      Shortness of breath, lassitude (3)      Palpitations (4)   Signs of cardiorespiratory adjustment to anemia exertive dyspnea (5)      Noted pallor

2.   Special manifestation

※

(1) Signs and symptoms of gastrointestinal tract a.   Glossitis b.   Angular stomatitis c.    Gastric atrophy d.   Postcrycoid web(Plummer-Vinson syndrome) (2)Pica-----one peculiar symptom is quite characteristic of iron deficiency. (3)Menorrhagia (4)Others ， koilonychia is a relative peculiar physical sign

Laboratory findings 1.   Peripheral blood (1)   Hemoglobin decreased (2)   Red cells are hypochromic and microcytic MCV<80um3 MCHC<32% 2.  Bone marrow---An absence of blue staining iron in the granule; Hypercellular BM, especially the erythroid system 3.   Serum iron iron-deficiency anemia serum iron ↓ serum ferritin ↓ TIBC ↑ Saturation of transferrin ↓ red cell protoprophyrin ↑

Diagnosis 1.Clinical manifestation 2.The laboratory findings The serum ferritin is the best figure that can reflect the quantity of storage iron. So it is the most sensitive and reliable figure. Usually, we regard serum ferritin<12ug/L as the diagnostic index of iron deficiency. 3.Therapy with iron is effective----Therapeutic Trial of Iron

Differential diagnosis Table: The kinds of Hypochromic Anemia With decreased body iron stores Iron deficiency anemia With normal or increased body iron stores Impaired iron metabolism Anemia of chronic diseases Defective absorption, transport, or utilization of iron Disorders of globin synthesis Thalassemia Other microcytic hemoglobinopathies Disorders of heme synthesis: sideroblastic anemias Hereditary Acquired

Table: differential diagnosis of hypochronic and microcytic anemia IDA

Thalassemia

ACD

Sideroblast ic anemia

Serum Ion

↓

N

↓

↑

TIBC

↑

N

↓

N

Serum ferritin

↓

N

↑

↑

Red cell proprohyrin

↑

N

↑

↑ or No

Therapy 1.   The etiological treatment ※ 2.   Supplement iron (1)  Oral iron a.   Ferrous sulfate b.   Response ： Reticulocyte c.   The reasons of no response

(2)      Parenteral iron A.   Indications : a. Malabsorption of intestine b. There are gastrointestinal complications , such as peptic ulcer, vomiting of pregnancy which can affect the absorption of oral iron. c.  There are severe gastrointestinal reaction even if the dosage iron has been decreased. d.  There is severe chronic bleeding exceeding the amount of iron which can be absorbed. e.   At the later period of pregnancy and complicate severe iron-deficiency anemia. B.  Iron-dextran complex  A formula for the dosage

3.   Blood transfusion

 Prognosis

Key points 1. The etiology of Iron deficiency anemia 2. The clinical manifestations of iron deficiency anemia 3. Indications of parenteral iron