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Jan 03, 2016
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بسـم الله الرحمن الر حیـم
هوالطیف
Overview of Overview of IDD assessment IDD assessment and indicators and indicatorsH. Delshad M.DEndocrinologistResearch Institute for Endocrine Sciences
IDDIDD: Iodine Deficiency Disorders: Iodine Deficiency Disorders
The world’s most common endocrine problem
The most preventable cause of mental retardation
The easiest of the major nutritional deficiencies to correct
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WWhat hat isis Iodine Iodine??
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● ● Iodine is a chemical element Iodine is a chemical element ( as are Oxygen ,Hydrogen , Iron ) ( as are Oxygen ,Hydrogen , Iron ) occurs in a variety of chemical formsoccurs in a variety of chemical forms
●● Iodine is an essential trace Iodine is an essential trace element for the humanelement for the human
●● Iodine is an essential Iodine is an essential part of the chemical part of the chemical structure of thyroid structure of thyroid hormoneshormonesTotal quantity present in body is (15-20 mg)
Mostly in thyroid gland
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What does iodine do? And
Why do we need iodine?
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Thyroid hormones synthesis
requires:
◦Normal thyroid gland◦Adequate secretion of T.S.H
◦Availability of iodine
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IodineIodineThe average adult body contains
between 20-50 mg iodine.60% of total iodine is
concentrated in thyroid gland. Iodine is an essential component
of the thyroid hormones. Iodine contributes 65% of T4 and
59% of T3 molecular weight.
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Thyroid horm
one synthesis
How much iodine should
we get?
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Recommended daily intake Recommended daily intake of iodineof iodine
Preschool children 90 g
Schoolchildren (6-12 y) 120 g
Adult (>12 y) 150 g
Pregnant & Lactating women
250 g
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Where do we get iodine from?
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Source of iodine
Water Food
Most of the iodine ingested by humans comes from food of animal and plant origin.
This iodine in turn, is derived from the soil.
Only a relatively small fraction is derived from drinking water.
Worldwide soil distribution of iodine is extremely variable & food grown in areas of low iodine does not contain enough of the mineral to meet requirements.
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Iodine sourcesIodine sources
Iodine sourcesIodine sources
Vegetables grown in iodine rich soil like kelp and onions
Milk & milk productSalt water fish and seafood
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Iodine deficiency – Disease of the soilIodine deficiency – Disease of the soil
Melting of Glaciers
Floods
Rivers changing course
Gradual leaching of iodine from soil due to:
Iodine deficient areasIodine deficient areas
Large population who are living in an environment where the soil has been deprived of iodine are at risk of IDD. ◦Mountainous region of Europe◦The northern Indian subcontinent◦The extensive mountain ranges of
china◦The Andean region in South America
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What happens if we don’t get
enough iodine?
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Mechanisms involved in the adaptation Mechanisms involved in the adaptation to iodine deficiencyto iodine deficiency
Increased thyroid clearance of plasma inorganic iodine.
Hyperplasia of the thyroid and morphologic abnormalities
Changes in iodine stores & TG synthesisModifications of the iodoamins acid
content of the gland.Enrichment of thyroid secretion in T3Enhanced peripheral conversion of T4 to
T3Increased T.S.H production
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The spectrum of The spectrum of IDDIDDFetus Abortions
StillbirthsCongenital anomaliesIncreased perinatal mortalityNeurologic creatinismPsychomotor defects
Neonate Neonatal goiterNeonatal hypothyroidims
Child & adolescent Goitrous juvenile hypothyroidism Impaired mental function Retarded physical development
Adult Goiter with its complications HypothyroidismImpaired mental function
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IDDIDD : Spectrum of Disorders : Spectrum of DisordersIDDIDD : Spectrum of Disorders : Spectrum of Disorders
From SIMPLE GOITER
Large MNG
Hypothyroidism
Severe myxedema
IQ
Psycho motor alteration
Deaf- Mutism
Diplegia
Retarded growth
.
.
To CRETINISM
Specific iodine deficiency Specific iodine deficiency disordersdisorders
Endemic goiterEndemic cretinism
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Endemic goiterEndemic goiter
More than 5% of the preadolescent (6-12 years) school age children have enlarged thyroid glands.
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Simple (nontoxic goiter)
WHO Region Population Population affected by goitre
In millions In millions % of the Region
Africa
612 122 20%
The Americas
788 39 5%
South-East Asia
1477 172 12%
Europe
869 130 15%
Eastern Mediterranean
473 152 32%
Western Pacific
1639 124 8%
Total 5858 741 13%
World wide prevalence of goiter
Pathogenesis of goiter Pathogenesis of goiter
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Impaired hormone synthesis • Iodine deficiency • Goitrogen in the diet• Dyshormogenesis
T.SH Alter sensitivity
Thyroid follicular cellHyperplasia and hypertrophy
Thyroid enlargement (GOITER)
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Three women of the Himalayas with typical endemic goiters.
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Huge Multinodular goiter
Iodine deficiency in the Iodine deficiency in the fetusfetus
Mental retardation:◦Is the result of iodine deficiency in
the mother◦Insufficient supply of TH to the
developing brain may result in mental retardation.
◦During the first and second trimesters of pregnancy the supply of the TH to the growing fetus is almost exclusively of maternal origin.
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Importance of iodine in brain development Importance of iodine in brain development
50,000 brain cells produced per
Second in developing fetal brain
90 % of human brain development occurs between 3rd month of
pregnancy & 3rd year of life
(Critical period)
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Importance of iodine in brain development Importance of iodine in brain development
Deficiency of iodine during this critical period of
development results in permanent brain damageThis brain damage can primarily be prevented by
correcting iodine deficiency before & during
pregnancyThis makes it vital that all expectant & lactating
mothers get their daily requirement of iodine
Importance of iodine in brain development Importance of iodine in brain development
Iodine deficiency is single most common cause of mental handicap worldwide
It is totally preventable
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Congenital Hypothyroidism
Endemic CretinismEndemic Cretinism
Is now largely a disease in remote, underdeveloped areas of the third world.
It occurs when iodine intake is below a critical level of 25 g/day
It is an irreversible changes in mental development of the fetus born in an area of endemic goiter.
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1% - 10%
Cretinism
5% - 30%
Some brain damage
30% - 70%
Loss of energy due to hypothyroidism
Cretinism, Tip of the Iceberg
Endemic CretinismEndemic Cretinism(Neurologic Form)(Neurologic Form)
Sever mental deficiencyDeaf mutism (Cochlear lesion)Motor spasticity (spastic diplegia) proximal rigidity of both lower and upper extremities and the trunk. Goiter
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Endemic CretinismEndemic Cretinism(Neurologic Form)(Neurologic Form)
Endemic CretinismEndemic Cretinism(Myxedematous Form)(Myxedematous Form)
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Less sever degree of mental retardation Sever growth retardationPuffy featuresMyxedematous and dry skinDelayed sexual maturation No goiter
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An adult male from the Congo,
with three women of the same
age (17-20 years),
all of whom are myxedematous cretins.
Myxedematous Cretinism
Myxedematous Myxedematous CretinismCretinism
Iodine deficiency is a prerequisite in the etiology of the disorder.
Three additional factors, acting alone or in combination may be responsible for thyroid atrophy. ◦Thiocyanate overload resulting from the
chronic consumption of poorly detoxified cassava.
◦Thiocyanate crosses the placenta and inhibits the trapping of iodine by the placenta and fetal thyroid.
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Cont’dCont’d
◦Selenium deficiency:H2O2 is produced in excess in thyroid
cells hyperstimulated by T.S.H H202 within the thyroid cells couldinduce thyroid cell destruction.
Selenium detoxifies H202 ◦Blocking autoantibiotdies.
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Specific Etiologies of Specific Etiologies of GoiterGoiter
Congenital goiter◦Familial: genetics disorders of
hormongenesis◦Sporadic:
Intrauterine iodide deficiency Fetal exposure to goitrogen (Antithyroid
drugs)
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Cont’dCont’dEndemic goiter
◦Iodine deficiency◦Dietary goitrogen
Cabbage Turnip Kale Rape Cassava
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Cont’dCont’d
Sporadic goiter Iodine excess
Wolff-chaikoff Jodbusedow
◦Goitrogenic drugs
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Drugs reported to cause goiterDrugs reported to cause goiter
Agent MechanismsIodide Inhibition of TH release and
synthesis
Thionamides Inhibition of tyrosyl iodination and coupling
Aminoglutethimide Inhibition of iodide organization
Lithium Inhibition of iodide organization
Amiodaron Inhibition of TH synthesis
Fluoride Exacerbation of effects of iodide deficiency
Carbutamide Decreased iodide uptake and inhibition of TH synthesis
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You