wu chunmei anemia due to impaired iron metabolism
TRANSCRIPT
Wu Chunmei
Anemia due to Impaired Iron Metabolism
This group disorders are caused by impaired iron metabolism which include:(a) Iron deficiency anemia: deficiency of iron(b) Sideroblastic anemia:`impaired utilization of iron(c) Anemia of chronic disease: defective iron reutilization
Iron Metabolism
The total body iron varies from 3 to 4 g, depending on the sex and weight of the individual. It is greater in males than in females and it increases roughly in proportion to body weight.
Male: 50-55mg/KgFemale: 35-40mg/Kg
1ml blood=0.5mg Fe
1gHb=3.3mgFe
1mlRBC=1~2mgFe
Amount and distribution:
Compartments iron content(mg) total body iron(TBI)
Hb iron: 2670 60-70% Tissue iron myoglobin 140 3.3% Labile iron pool 80-90 2.2% cytochromes 8 0.2% catalase peroxidase Storage (available) iron Ferritin 440 30% Haemosiderin 390Transport iron 3 0.1%
The iron is distributed in several forms:
Balance of iron metabolism Absorption ----excretion
Absorption
Transport of iron
Utilization
Affecting factors?
Fe 3+ in food
combined
Free Fe 3+ stomach
reduced(VitC, GSH) gastric juice
Fe 2+
Duodenum and upper jejunum
Epithelial cells brush border
apo-Ferritin + Fe 3+ Fe 2+
ferritin
receptor reductase
Fe 2+
Circulation Fe 2+
Tf + Fe 3+
Tf-Fe 3+
Storage inMMS
Ferritin Haemosiderin
In tissue:myoglobin heme-containing enzymes
liver
Iron cycle
Normablasts
Ret.
marrow for Hb
absorption
Trans-port
transferrin Serum beta-globulin that binds and transports irontransferrin receptors
Transport of iron
MMS
Ferritin:
Haemosiderin:
Storage of iron
apoferritin
+
Fe
An iron-containing protein complex that is formed by a combination of ferric iron with the protein.(apoferritin)
insoluble storage iron, golden yellow or brown granules in unstained tissue; blue granules when stained with potassium ferrocyanide. It contains more iron than ferritin and aggregates into granules, microscopically visible in tissue and phagocytes.
Iron utilized in normoblast
Tf
Fe 3+ Fe 2+
protophorphyrin
+
Fe 2+
Heme
Heme+globin Hb
Ferritin
80%
sideroblasts
Fe 3+
Tf-Fe 3+
1/3
SA
Hb
heme globin
Fe 3+ Fe 2+
Hemosiderin
ferritin
apo-Ferritin
Old RBC
Storage iron in macrophages
Normoblasts
Hepatocytes
Placental cells
have more receptors
Reutilization of Iron
blood
IRON DEFICIENCY ANEMIA (IDA)
Iron deficiency is the state in which the content of iron in the body is less than normal. When the supply of iron to the marrow is insufficient for the requirements of Hb synthesis, IDA develops with varying degrees of microcytic hypochromic anemia.
C: Increased requirements--Early childhood and adolescence--Women during the reproductive years
Causes of iron deficiency :
A: Decreased iron intake--Poor diet--Impaired absorption
B: Increase iron loss (1ml blood =0.5mgFe)--losses from gastrointestinal tract --Neoplasm --Peptic ulcer --Others (hookworm disease)--Menometrorrhagia --Losses from urine (PNH)--Losses from sputum (rare)
--Lack of iron interferes with heme synthesis, which leads to reduced Hb synthesis and defective erythropoiesis.
--There is decreased activity of iron-containing proteins.
--Neurologic dysfunction may occur, with impaired intellectual performance, paresthesias, etc.
--Gastric acid secretion is reduced, often irreversibly.
--Atrophy of oral and gastrointestinal mucosa may occur
Pathogenesis of ID
Clinical Features
1. General symptom of anemia:Fatigue,weakness,or palpitations, headache
2. Essential iron deficiency:
--Children may have poor attention span, poor response to sensory stimuli, retarded developmental and behavioral achievement, irritability and retarded longitudinal growth.
--Paresthesias and burning of tongue may occur.
--Pica, craving to eat unusual substances such as clay,or ice, is a classic manifestation.
Physical examination
Pallor
Smooth red tongue, stomatitis
Angular cheilitis
Koilonychia(rare)
Retinal hemorrhages/exudates(severe anemia)
Accelerated retinopathy in diabetics
Splenomegaly(occasionally)
• RBC↓,Hct ↓, Hb ↓ :male<120g/l, female<110g/l, pregnant women<100g/l, MCV<80gl, MCH<26g, MCHC<31%•RDW ↑(>14%, earliest change )•morphology: anisocytosis , mild ovalocytosis, target cells, ring cells, elongated hypochromic elliptocytes (pencil cells), nucleated RBC, basophilic stippling RBC
•Ret normal or reduced
•Leukocyte normal or decreased•Platelets increased or decreased
Laboratory Findings
1.Blood : Hypochromic microcytic anemia
IDA 早期血象:红细胞生成缺铁期,部分红细胞生理性中心浅染区轻度扩大,临床上无贫血
• marrow usually hypercellularity with M/E ratio variable.
• morphology: erythroid hyperplasia and mainly late normoblasts, which may be small, with narrow rim of ragged cytoplasm and poor Hb formation (polychromatic) and densed nucleus(old nucleated young cytoplasm). Basophiloic stippling and Howell-Jolly body may present in normoblasts.The mature RBCs as in blood.
2. Marrow: hypercellularity anemia
Nucleated cells marked hypercellularity
IDA 骨髓象:中幼红细胞、晚幼红细胞增生为主,胞体较小,胞浆边缘不规则呈锯齿状、胞浆偏蓝,呈“幼浆老核”现象。
HA
IDA
①Marrow stainable iron. Reference value: -extracellular iron (+~++) -intracellular iron (19%~44%)
It is a direct and reliable index to reflect the level of storage iron.
3 The indexes of iron metaolism
It decrease (<15%) , or absent in ID
Sideroblasts decrease in IDE
IDA 骨髓铁染色:外铁阴性
IDA 骨髓铁染色:内铁阴性
正常:内铁阳性
SF Reference value:
--< 10µg/l in IDA
--10 ~ 20µg/l are presumptive, but not diagnostic.
--May be elevated with concomitant inflammation diseases . IDA can be suspected in rheumatoid arthritis if SF is less than 60µg/l or less than 30µg/l in chronic inflammation.
It is a sensitive and reliable index to evaluate total body iron stores, but can be interfered by some conditions.
Adult male:50~200µg/l;
② SF(serum ferritin)and EF(erythrocyte alkaline ferritin )
EF reference value: less sensitive than SF, <6.5µg/E in IDA
Measurements of iron stores
Iron stores SF(µg/l ) Marrow iron stain(0-4+)
0 <12 0
1~300mg 12~20 1+
300~800mg 20~50 2+
800~1000mg
50~150 3+
1~2g 150~300 4+
Iron overload >500
③Serum iron concentration
SI is a direct measure of the amount of iron bound to transferrin.
Reference value:50-150µg/dl
transporting iron, with a lot of affect factors
Adult M:11.6~31.3µmol/l; F:9.0~30.4µmol/l(A:20µmol/l)
④TIBC: total iron binding capacity
TIBC is a measure of the amount of iron that can be bound by transferrin.
Reference value: 360~390µg/l
TIBC:male:50~77µmol/l; female 54~77µmol/l
•Usually increased in ID. • decreased in liver disease, malignant tumor, HA, chronic renal disease…
⑤TS (Transferrin Saturation): SI TS = ×100% , TIBC
In normal condition, 1/3 transferrin binds to iron.
Reference value: 20~50%. ( A:30%)
15% or less in patients with IDA ; >50~60% resulting in iron loading.
UIBC
SI
TIBC
⑥sTfR(serum soluble transferrin receptor) :
Reference value: 5~9μg/L(ELISA)
sTfR level increase in IDE, IDA (when iron store are exhausted)
sTfR level also increase in other disease with ineffective or effective erythroid precursor proliferation
--usually increased in ID
--Very sensitive for diagnosis of ID and
suitable for large-scale screening of children ,
detecting both ID and lead poisoning.(why?)
⑦ FEP (Free Erythrocyte Protophorphyrin) and ZPP( protophorphyrin binds to zinc)
FEP less sensitive than SF and EF.
Sensitivity of indexes of iron:
Marrow stainable iron SF
EF
FEP
TIBCTS
SI
sTfR
Diagnosis of IDA: +more than two of ① ②~⑧
①Hypochromic microcytic anemia(Hb male < 120 g/l , female<110g/l, pregnant women<100g/l, MCV < 80fl, MCH<26g, MCHC < 31% , RDW > 14% , and morphologic changes)
② Identified causes associated with ID and significant clinical symptoms
③ SI <10.7µmol/L,and TIBC>64.44 µmol/L
④TS<0.15
⑤ Extracellular iron ( - ), sideroblasts <15% or absent
⑥ FEP>0.9 µmol/L(blood) ,or ZPP>0.96umol/L(blood), or FEP/Hb >4.5µg/gHb
⑦ SF<14µg/L; ⑧ Effective to therapy with iron
1. Iron depletion (ID): It is the earliest stage of iron deficiency. In which storage iron is decreased or absent but serum iron concentration and blood Hb levels are normal.
---Extracellular iron is decreased or absent ---SF concentration falls
There are three stages of iron deficiency:
2.Iron deficiency erythropoiesis (IDE):
It is a somewhat more advanced stage of iron deficiency. In which deficit of the functional iron compartment is associated with the development of iron deficiency erythropoiesis. It is characterized by decreased or absent storage iron, usually low SI and transferrin saturation, without frank anemia.
--Extracellular iron is absent--Intracellular iron is decreased--Serum soluble transferrin receptor(sTfR) is increased.--TIBC is increased--Serum iron level falls--Transferrin saturation falls--An increase in the RDW--generally asymptoms.
manifestations
3.Iron deficiency anemia (IDA):
It is a most advanced stage of iron deficiency. It is characterized by decreased or absent iron stores, low SI , low transferrin saturation and low Hb or hematocrit value. Besides the above characteristics, there are:--red cell count decrease --Many symptoms
Laboratory studies in three stages if iron deficiency
ID IDE IDA
hemoglobin Normal slight decrease Marked decrease (microcytic/hypochromic)
Iron stores <100mg(0-1+) 0 0
SI (μg/dl) normal <60 40
TIBC(μg/dl) 360-390 >390 >410
TS(%) 20-30 <15 <10
SF((μg/l)
)
<20 <12 <12
Percent sideroblasts
40-60 <10 <10
FEP(μg/dlRBC) 30 >100 >200
Diagnosis process of
-Anemia?
-Microcytic hypochromic anemia?
-IDA?(measurements of iron metabolism)
-The cause of IDA!
Sideroblastic Anemias (SA)
The sideroblastic anemias are a heterogeneous gr
oup of disordes that have as common features the p
resence of large number of ringed sideroblasts in th
e marrow, ineffective erythropoiesis, increased level
s of tissue iron and varying proportions of hypochr
onic erythrocytes in the blood.
hereditary: x chromosome-linked ,partially recessive inheritance, males are anemic and females are carriers. autosomally-linked, or mitochondria entitiesacquired : primary: neoplasia (MDS-RAS) secondary: drugs, toxin, alcohol, or coincident to neoplastic or inflammatory disease
Classification:
1.underlying biochemical lesions
Sideroblasts appear by a defect of pyridoxine metabolism or other intramitchondrial defect in heme synthesis.
2. anemia: ineffective erythropoiesis
Pathogenesis: not clear
铁的利用与血红蛋白合成示意图
Fe 3+
Tf-Fe 3+ Tf
Fe 3+ Fe 2+
protophorphyrin
+
Fe 2+
Heme
Heme+globin Hb
Ferritin
80%
骨髓:幼红细胞和网织红细胞血浆
TfR
Pathway of heme Biosynthesis
UROI COPRO I
UROgen I UROgen I
Gly
Succinyl CoAALA PBG
线粒体
Heme
⑤Heme synthetase
UROgen III
COPROgenIIIPROTOgenIII
PROTO9
UROIII
COPROIII
Fe
①ALA synthetase
pyridoxinePhosphate pyrindo
xine
②Phosphate pyridoxine
③
④
⑥
Lab Findings
--Hypochromic and micro- or normocytic anemia
--Marked anisocytosis and poikilocytosis
--Normal or elevated SI levels
--Erythroid hyperplasia of the BM
--Increased siderablasts in BM, ringed sideroblasts
--Increased iron stores
--Normal or slightly reduced red cell survival time
--Hemosiderosis and/or hemochromatosis
[Others] Refractory to therapy with iron
Anemias of Chronic Disorders(ACD)
Anemias of chronic disorders are present in chronic infections, inflammatory diseases and neoplastic diseases .
It is a common anemia, probably second in incidence to iron deficiency anemia.
Secondary anemia-------
--Sequestration of iron in the macrophages
SI ,TS decrease
--reduce the secretion of EPO and impair its
action in marrow Tf, sTfR ,TIBC decrease
--Shortened RBC life span (slightly hemolysis)
Pathogenesis of ACD
Tf
Fe 3+ Fe 2+
protophorphyrin
+
Fe 2+
Heme
Heme+globin Hb
Ferritin
80%
Fe 3+
Tf-Fe 3+
ACDReutilization of iron impaired Hypochromatic anemi
a
Hb
heme globin
Fe 3+ Fe 2+
Hemosiderin
ferritin
apo-Ferritin
Macrophages
Neutrophils
Inflammatory cells
growth factors-IL 1
Precursor cells
Cytokines, such as IL 1 , TNF ,gamma interferon.
SF, extracellular iron increase
Clinical Features
--Signs common to all anemias.
--Signs specific to the underlying disease.
--Showing no improvement with iron therapy and only improving with correction of the primary disorders.
Bone marrow
--No distinctive abnormality
--Iron stains shows increased stainable iron in the macrophages despite a decrease in sideroblasts.
Other Test
--SI decrease, Tf decrease
--SF is normal or increased
--TIBC is normal to decreased
--TS is usually decreased
Lab Findings
1.Describe the characteristics of three stages of iron deficiency.
2. Describe the causes of iron deficiency.
3. How to diagnose ID? IDE? IDA?
4. What is IDA? Sideroblast? Ring sideroblast?
5. What is ferritin? Tf ? TIBC? SI?
6.How to differentiate hypochromatic microcytic anemias in Lab?
Questions:
Differential Diagnosis in Lab
Lab test Thalassemia ACD IDA
RBC low low low
MCV 60-70 low in 20-30% rarely to 60-70
Tf N decrease increase
SF N/Increased N/Increased low
SI N to high low low
HbA2,F,H usually present absent absent
TIBC N/ low usually low usually high
TS N to high > 15%, low low or N
Extracelluiar iron N increase decrease
Intracellular iron N decrease decrease
Case
A female, complained of fatigue and headache for a few months since she had functional uterine bleeding and short of breath when climbing stairs
The doctor found her face look pale. He ordered an CBC detection. The result is the follow.
Ret is 2.5%
Result of CBC
外周血涂片染色
骨髓细胞学检查。
Questions:
1.Does the female has anemia?
2. Do you think which type anemia she has?
Give your reasons.
3. Which tests do you need to confirm your advice. Do you image the results?