GROWTH AND DEVELOPMENT. Growth means natural increase in size or dimensions i.e. weight and length as well as the size of different organs, not necessarily.

GROWTHGROWTH AND AND

DEVELOPMENTDEVELOPMENT

Growth means natural increase in size or dimensions i.e. weight and length as well as the size of different organs, not necessarily associated with functional maturation. This is achieved by cell multiplication and by increase in the intercellular substances.

Development means functional maturation gaining or acquisition of skills.

In the normal human being growth and development run parallel to each other.

STAGES OF GROWTH STAGES OF GROWTH AND DEVELOPMENTAND DEVELOPMENT

I) Prenatal or intra uterine stageI) Prenatal or intra uterine stage

II) Postnatal or Extra uterine II) Postnatal or Extra uterine stagestage

I) Prenatal or intra uterine I) Prenatal or intra uterine stagestage

1- Embryonic period (1st 8 weeks)1- Embryonic period (1st 8 weeks)During this period the fertilized ovum During this period the fertilized ovum divides and differentiates rapidly to form divides and differentiates rapidly to form most of the organs of the body. So it is most of the organs of the body. So it is called period of organogenesis. called period of organogenesis.

Any abnormal event in this period will Any abnormal event in this period will disturb the normal pattern of organs disturb the normal pattern of organs formation and result in formation and result in eithereither congenital congenital anatomical malformation anatomical malformation or or abortion.abortion.

22 - -Fetal period (9th – 40th weeks)Fetal period (9th – 40th weeks)It is characterized by increase in size It is characterized by increase in size (growth) as well as (development) of the (growth) as well as (development) of the already organized (formed) fetus.already organized (formed) fetus.Placenta gets formed and takes its role in Placenta gets formed and takes its role in fetal nutrition. Sometimes it is called fetal nutrition. Sometimes it is called placental period.placental period.Any abnormal event in this period will not Any abnormal event in this period will not affect organogenesis but fetal growth and affect organogenesis but fetal growth and development might be greatly disturbed development might be greatly disturbed miscarriage, premature delivery, still birth miscarriage, premature delivery, still birth or intra uterine growth retardationor intra uterine growth retardation..

Fetal period is divided into:-Fetal period is divided into:-Early fetal period (9th – 28th w)Early fetal period (9th – 28th w)Late fetal period (28th – 40th w)Late fetal period (28th – 40th w) ****Early fetal period (9th – 28th w)Early fetal period (9th – 28th w)::More growth in length than in weight More growth in length than in weight (35 cm, 1 kg).(35 cm, 1 kg).Fetus is pre-viable because of Fetus is pre-viable because of incomplete development of pulmonary incomplete development of pulmonary alveolar systemalveolar system..

****Late fetal period (28th – 40th w)Late fetal period (28th – 40th w)More growth in weight than length (50 More growth in weight than length (50 cm, 3.35 kg).cm, 3.35 kg).Fetus is viable. Important substances Fetus is viable. Important substances pass from the mother to the fetus pass from the mother to the fetus through placenta during that period e.g. through placenta during that period e.g. calcium, iron, vit D, vit K, coagulation calcium, iron, vit D, vit K, coagulation factors and gamma globulins (formation factors and gamma globulins (formation of body stores)of body stores)..

II) Postnatal or Extra-uterine II) Postnatal or Extra-uterine stagestage

It is characterized by full activity and self It is characterized by full activity and self responsibility of the developing responsibility of the developing organism.organism.

It is divided into:-It is divided into:-A. Neonatal period (1st 4 weeks)A. Neonatal period (1st 4 weeks)It is characterized by physiological It is characterized by physiological

adaptation and adjustment to the new adaptation and adjustment to the new extra uterine environment.extra uterine environment.

B. Infancy period (1st 2 years)B. Infancy period (1st 2 years)It is characterized by:-It is characterized by:-1- Feeding and weaning.1- Feeding and weaning.2- Higher rate of growth & 2- Higher rate of growth & development.development.3- Eruption of all milk teeth.3- Eruption of all milk teeth.4- Immunity against many of the 4- Immunity against many of the infectious diseases.infectious diseases.5- Development of most of 5- Development of most of milestonesmilestones..

C. Childhood period (2 -12 years)C. Childhood period (2 -12 years)It is characterized by social and It is characterized by social and educational maturationeducational maturation..

D. AdolescenceD. AdolescenceIt is characterized by sexual and It is characterized by sexual and psychosomatic maturation as well as psychosomatic maturation as well as another spurt of physical growthanother spurt of physical growth..

FACTORS AFFECTING GROWTH FACTORS AFFECTING GROWTH AND DEVELOPMENTAND DEVELOPMENT

1- 1- Herido-constitutional factorsHerido-constitutional factors

2- Maternal factors during pregnancy 2- Maternal factors during pregnancy

3- Endocrinal factors3- Endocrinal factors

4- Nutritional factors4- Nutritional factors

1- Herido-constitutional factors:-1- Herido-constitutional factors:-

e.g. sex, race, familial factors, certain e.g. sex, race, familial factors, certain congenital anomalies or familial congenital anomalies or familial diseasesdiseases which interfere with prenatal which interfere with prenatal or postnatal growth.or postnatal growth.

2- Maternal factors during 2- Maternal factors during pregnancy:-pregnancy:- Non-infections e.g. hypertension, Non-infections e.g. hypertension, D.M., eclampsia.D.M., eclampsia. Maternal infection e.g. german Maternal infection e.g. german measles, toxoplasmosis…..measles, toxoplasmosis….. Maternal drug intake, smokingMaternal drug intake, smoking Maternal exposure to hypoxia.Maternal exposure to hypoxia. Nutritional status of the mother Nutritional status of the mother during pregnancy.during pregnancy.

3- Endocrinal factors:-3- Endocrinal factors:- During fetal period: chorionic During fetal period: chorionic gonadotropins & placental growth factors.gonadotropins & placental growth factors. Infancy & childhood: Infancy & childhood:

Growth hormone: for linear growth Growth hormone: for linear growth

Thyroxine hormone: for skeletal Thyroxine hormone: for skeletal maturationmaturation Adolescence: sex hormones Adolescence: sex hormones (androgens and estrogens) share.(androgens and estrogens) share.

4- Nutritional factors:-4- Nutritional factors:-

Malnutrition and under nutrition Malnutrition and under nutrition growth retardation. growth retardation.

ASSESSMENT OF GROWTH ASSESSMENT OF GROWTH AND DEVELOPMENTAND DEVELOPMENT

A) Physical growthA) Physical growth

B) DevelopmentB) Development

Physical growthPhysical growthAA) Anthropometric measures:) Anthropometric measures:1) Weight1) Weight

a) Birth weight 3- 3.5 kga) Birth weight 3- 3.5 kg..

b) Physiological weight loss about 6 – b) Physiological weight loss about 6 – 10 % of birth weight10 % of birth weight..

It occurs during 1st few days and It occurs during 1st few days and regained by 10th day.regained by 10th day.

It is due to: It is due to: 1- Scanty milk and fluids intake.1- Scanty milk and fluids intake. 2-Natural loss of body fluids in urine & 2-Natural loss of body fluids in urine &

stool.stool.

c) During 1st 4 months weight c) During 1st 4 months weight increases by 3/4 kg / monthincreases by 3/4 kg / month..

During 2nd4 months weight increases by During 2nd4 months weight increases by 1/2 kg / month.1/2 kg / month.During 3rd 4 months weight increases by During 3rd 4 months weight increases by 1/4 kg / month.1/4 kg / month.

d) Thus: body weight at 4 months: 6 kg, at d) Thus: body weight at 4 months: 6 kg, at 8 months: 8 kg, at one year: 9 kg.8 months: 8 kg, at one year: 9 kg.

e) After the 1st year:- Weight in kg = (Age e) After the 1st year:- Weight in kg = (Age in years X 2)+ 8 in years X 2)+ 8

22 - -Linear growthLinear growth

LengthLength is crown to heal measurement is crown to heal measurement in recumbent position.in recumbent position. HeightHeight is the same measurement in is the same measurement in standing position.standing position. LengthLength is measured in recumbent is measured in recumbent position in children up to 4 years.position in children up to 4 years. Height Height is measured while child is is measured while child is standing (stature).standing (stature).

Length Length is measured in recumbent position is measured in recumbent position in children up to 4 years.in children up to 4 years.HeightHeight is measured while child is standing is measured while child is standing (stature).(stature). = +4 (in Length is more than height by 0.5 = +4 (in Length is more than height by 0.5 – 1 cm due to relaxation of ligaments during – 1 cm due to relaxation of ligaments during lying down and compression of the spine lying down and compression of the spine during standing.during standing. Normal length at birth is 50 cm, at 1 year Normal length at birth is 50 cm, at 1 year 75 cm, at 2 years 87.5 cm.75 cm, at 2 years 87.5 cm.After 2 years, length in cm = (Age in years X After 2 years, length in cm = (Age in years X 5) + 805) + 80

Proportion of upper to lower Proportion of upper to lower segment:segment:

At birth 1.7 : 1, at 3 years 1.3 : 1, in At birth 1.7 : 1, at 3 years 1.3 : 1, in adult 1 : 1.adult 1 : 1. Arm - span and height: Arm - span and height:

Arm span – height = -3 at 1 – 7 yearsArm span – height = -3 at 1 – 7 years

= 0 at 8 – 12 years= 0 at 8 – 12 years

males) & +1 (in female)males) & +1 (in female)

33--Head circumferenceHead circumference

It gives an idea about brain growth.It gives an idea about brain growth.At birth head circumference = 35 cm.At birth head circumference = 35 cm.At 1 year : 45 cm - At 2 year : 47 cmAt 1 year : 45 cm - At 2 year : 47 cmAt 5 years : 50 cm - At 12 years : 55 At 5 years : 50 cm - At 12 years : 55 cm.cm.

44 - -Mid-arm circumferenceMid-arm circumference

It is about 12 -14 cm in normal child It is about 12 -14 cm in normal child between 1 – 4 years between 1 – 4 years It gives an idea about muscles mass, It gives an idea about muscles mass, and it is best and early predictor of and it is best and early predictor of malnutrition.malnutrition.

B) Skull fontanellesB) Skull fontanelles:: There are 6 fontanelles : 4 lateral, There are 6 fontanelles : 4 lateral, clinically insignificant, one anterior clinically insignificant, one anterior and one posterior.and one posterior. Anterior fontanelle is 3 fingers in Anterior fontanelle is 3 fingers in transverse diameter at birth, 2 fingers transverse diameter at birth, 2 fingers at 6 months,1 finger at 1 year, close at 6 months,1 finger at 1 year, close at 18 monthsat 18 months . . Premature closure: microcephaly Premature closure: microcephaly and craniosynostosis.and craniosynostosis.

Bulging ant. fontanelle: intracranial Bulging ant. fontanelle: intracranial tension e.g. intracranial hemorrhage, tension e.g. intracranial hemorrhage, meningitis, encephalitis and meningitis, encephalitis and hydrocephalus.hydrocephalus. Depressed ant. fontanelle: collapse of Depressed ant. fontanelle: collapse of extracellular fluid in shock and extracellular fluid in shock and dehydration.dehydration. Delayed closure of ant. fontanelle: Delayed closure of ant. fontanelle: rickets, Down's syndrome, rickets, Down's syndrome, hypothyroidism (cretinism), hypothyroidism (cretinism), hydrocephalous, achondroplasia, hydrocephalous, achondroplasia, osteogenesis imperfecta.osteogenesis imperfecta.

C) TeethingC) Teething::Deciduous teethDeciduous teeth (milk teeth): 20 in (milk teeth): 20 in number.number.6 – 9 months central incisors appear.6 – 9 months central incisors appear. 9 – 12 months lateral incisors9 – 12 months lateral incisors 12 – 18 months 1st molar.12 – 18 months 1st molar. 18 – 24 months canine.18 – 24 months canine. 24 months 2nd molar.24 months 2nd molar.Age in months = number of teeth + 6.Age in months = number of teeth + 6.

Permanent teethPermanent teeth: 32 in number. : 32 in number. Eruption of the permanent teeth:Eruption of the permanent teeth:

First molars 6 – 7 years.First molars 6 – 7 years.Central incisors 6 – 8 years. Central incisors 6 – 8 years. Lateral incisors 7 – 9 years. Lateral incisors 7 – 9 years. Canines 9 – 10 years.Canines 9 – 10 years.First premolars 10 – 11 years. First premolars 10 – 11 years. Second premolars 11 – 12 years.Second premolars 11 – 12 years.Second molars 12 – 13 years.Second molars 12 – 13 years.Third molars (wisdom tooth)17 – 22 years.Third molars (wisdom tooth)17 – 22 years.

D) Appearance of ossific centersD) Appearance of ossific centers:: In the fetus: In the fetus:

5-6th month: calcanum, 7-8th month: 5-6th month: calcanum, 7-8th month: cuboid, 10th month: talus.cuboid, 10th month: talus.At birth: lower end of femur: 1 cm smooth, At birth: lower end of femur: 1 cm smooth, regular, well defined, and upper end of tibia.regular, well defined, and upper end of tibia.Two carpal bones appear after 2 months, Two carpal bones appear after 2 months, thenthenCarpal bones appear at a rate of one Carpal bones appear at a rate of one ossific center for every year.ossific center for every year.

Carpal bones appear at a rate of one ossific Carpal bones appear at a rate of one ossific center for every year.center for every year.

Chronic illness. At 6 years child has 7 carpal Chronic illness. At 6 years child has 7 carpal centers .centers .

The 8th carpal center (pisiform) appears by The 8th carpal center (pisiform) appears by age 12.age 12.

Ossesous development is retarded in:Ossesous development is retarded in: - Congenital hypothyroidism.- Congenital hypothyroidism. - Male hypogonadism.- Male hypogonadism. - Delayed adolescence.- Delayed adolescence. - Malnutrition- Malnutrition It is accelerated in obesity, adrenogenital It is accelerated in obesity, adrenogenital

syndrome and sexual precocity. syndrome and sexual precocity.

B) DevelopmentB) DevelopmentAA) Development of mentality) Development of mentality ::This can be assisted by:This can be assisted by:

Disappearance of neonatal reflexes.Disappearance of neonatal reflexes. Development of locomotor system.Development of locomotor system. Development of speech, hearing & Development of speech, hearing &

vision.vision. Development of sphincters control.Development of sphincters control. Social adaptation as recognition of Social adaptation as recognition of

mother, relatives, smiling, recognition of mother, relatives, smiling, recognition of surrounding and others.surrounding and others.

Learning ability in school.Learning ability in school. Also by I.Q. :Also by I.Q. :

50 – 75 % educable (morror).50 – 75 % educable (morror).35 – 50 % trainable (imbicil). 35 – 50 % trainable (imbicil). 0 – 35% idiot.0 – 35% idiot.

In normal child:• 2nd month: Social smile appears.• 4th month: Recognizing mother.• 9th month: Recognizing father.• 1 year: Speaking 2 – 3 words.• 2 years: Speaking 2 – 3 phrases.• 3 years: Can draw a circle.• 4 years: Can draw a triangle.

B) Development of Locomotor system:•It depends on: 1- Development of C.N.S. 2- Environmental factor which is training. 3- Development of peripheral locomotor system, bones, joints and muscles:

•4th month: head support, sitting support.• 6th month: sitting freely.• 9th month: crawling, standing supported.• 12th month: standing freely.• 15th month: walk freely.• 18-24th month: run freely, up and down stairs.• 3 years: ride a tricycle.

C) Development of speech:It occurs in 3 successive stages:

1 -Stage of vocalization (1st 2 months)Simple production of sounds by the vocal cords, no meaning , no purpose.

2 -Stage of babbling (2 – 6 months)Simple production of sounds by lips.

3 (Stage of vocal verbal play•Production of sounds which have meaning & purpose.•Development of speech depend s on 3 integral function units:- Reception, i.e. good hearing. Memorization, i.e. good mentality. Production, i.e. proper peripheral articulation.

D) Development of hearing:•At birth: impaired, tympanic cavity is filled with amniotic fluid.•1st & 2nd months: responds to sound by Moro reflex.•3rd & 4th months: responds to sound by cessation of movement and stopping crying.•5th &6th months: the infant turns his head to sound.•At 1 year: hearing ability becomes very fine.

E) Development of vision:•In the neonatal period infant cannot fixate, since the maculate are not well developed.•During the second month, the infant can fixate on a steady source of light.•At 3 months, he can follow slowly moving objects with his eyes.•At 6 months, he can follow rapidly moving objects.

F) Development of sphincteric control:

•It occurs at variable age from 1 – 4 years•It depend upon maturation of the pyramidal tract, training & psychological status.•Sphincteric disturbance after a period of normal control is considered pathological

G) Puberty:•It means beginning of sexual maturation.•The mean age for onset of puberty is 11.4 years & 12 years in boys.•It begins in girls breast development & in boys with testicular growth.

BoysGirls

Testicular growthBreast development

Public hair development

Pubic hair development

Growth of penis & scrotum

Maturation of external genitalia

Muscle bulk increasesFemale body habitus

Bread, axillary & body hair

Axillary hair

Oil secretion & acneOil secretion & acne

First seminal dischargeMenstruation

ASSESSMENT OF GROWTH

Assessment of growth is undertaken by a combination of accurate measurement and plotting on suitable growth charts.

a) Percentile growth chartsa) Percentile growth charts b) Road to health charts (Morly's b) Road to health charts (Morly's

chart)chart)

A) Percentile growth charts:•The word percentile means ranking (or arranging) a particular child compared to normal children of the same age and sex using a percentile chart .•There are separate charts for boys and girls and for each age group.•At the right end of each curve in a chart is a number starting from above 95, 90, 50, 25, 10, 5 percentile.•Children above 95th or below the 5th percentiles are most likely abnormal and need thorough evaluation.

B) Road to B) Road to health charts (Morly's charts (Morly's chart)chart)::

•Used for 1st 3 – 5 years of life only, for Used for 1st 3 – 5 years of life only, for both sexes.both sexes.•Only 2 curves on the chart, no percentile Only 2 curves on the chart, no percentile figures.figures.•Used for early detection of PEM flat Used for early detection of PEM flat curve, success treatment weight curve, success treatment weight increases. i.e. for comprehensive care increases. i.e. for comprehensive care and follow up at health centers.and follow up at health centers.

GROWTH RETARDATIONNormal growth is the aggregate expression of normal environmental, nutritional and genetic factors.

Failure to thrive: weight or height at least two standard deviation below the mean for children of the same age.

Short stature: subnormal height relative to other children of the same sex, age and ethnic background. Height is below the 3rd percentile for sex and age.

Stunting: height is less than 90% of the 50th percentile for age.

Dwarfism: indicates small size.

Infantilism: dwarfism as well as sexual retardation when the individual has passed the expected age of puberty.

CAUSES OF GROWTH CAUSES OF GROWTH RETARDATIONRETARDATION

Normal variantsNormal variants Pathologic G.R.Pathologic G.R.

I) Normal variantsI) Normal variants::

A) Familial short stature A) Familial short stature (Genetic):(Genetic):Either the parents or other healthy Either the parents or other healthy close relatives are short, bone age is close relatives are short, bone age is normal, birth size tends to be small, normal, birth size tends to be small, history and physical examination are history and physical examination are normal.normal.

B) Constitutional growth delay:

It represents the lower end of the normal range of skeletal and pubertal development. Birth size is normal, and infants grow normally for few months, then linear growth and weight gain slow down. Bone age remains roughly equivalent to height age.

The adolescent growth spurt does not come until after the age of 14 years in girls and 16 years in boys, but final adult height and sexual development are normal. There is history of delay growth and sexual development in other family members.

II) Pathologic G.RII) Pathologic G.R..

A) Disproportionate:A) Disproportionate:Measuring U/L segments and arm span minus height is useful in identifying this group. The most common causes of this type are:

Rickets and skeletal dysphasia e.g. achondroplasia and hypothyroidism..

B) Proportionate:I) Prenatal:

1.Intrauterine growth retardation due to intrauterine infections, cytomegalovirus, toxoplasmosis, rubella, herps simplex, syphilis and AIDS.

2. Chromosomal anomalies: Down's syndrome, Turner's syndrome.

3. Placental diseases, uterine tumors, twins, maternal vascular diseases and malnutrition (usually only restrict growth in utero).

4. Dysmorphic syndromes:-Syndromes of unknown etiology, identified by their unique clinical and radiological features. Bones age is not retarded. There is no treatable underlying cause of short stature.

II) Postnatal:1.Endocrine disorders:-• Hypopituitarism, either

panhypopituitarism or isolated growth hormone deficiency. There is deceleration of linear growth beginning in infancy, immature facies, trunkal obesity, microphallus, bone maturation is retarded, puberty is delayed.

• Diabetes Mellitus (DM): severe growth retardation occurs in poorly controlled DM, even children with fairly well controlled DM may sustain decrease of adult height if the disease appears before puberty.•Glucocorticoid excess: Cushing's disease or excess adrenal glucocorticoid intake. Affected children show moon facies, plethoric complexion, trunkal obesity, cervical dorsal fat bad, and cutaneous striae.

• Hypogonadism: sex hormones deficiency becomes a cause of G.R after age of 10 years in female and 12 years in male.

2 .Psychosocial dwarfism-:Factors include maternal depression and family disturbances. It is diagnosed by family and dietary history. It is due to suppression of hypothalamus by higher cortical centers.

3 .Malnutrition-: Decrease intake of proteins, calories, zinc and iron.

4 .Gastrointestinal disease-:Cystic fibrosis, chronic infections, malabsorption, parasitic infestation.

5 .Chronic anemias-:B-thalassemia, sickle cell anemia, iron deficiency anemia.

6 .Cardiopulmonary diseases-:• Chronic upper airway obstruction.• Congenital heart diseases, acquired heart

diseases.• Chronic lung diseases, asthma,

bronchiectasis, bronchopulmonary dysplasia, cystic fibrosis.

7.Renal diseases-:UT infections – Chronic renal failure – Renal tubular acidosis – Diabetes insipidus – Malformation or cystic disease.

8 .Chronic infections and inflammatory conditions-:

Tuberculosis, parasites, collagen diseases, immune deficiency diseases.

9 .Metabolic disorders-:Galactosemia, hypercalcemia, mucopolysaccharidosis, glycogen storage disease.

ASSESSMENT OF GROWTH ASSESSMENT OF GROWTH RETARDATIONRETARDATION

HistoryHistory ExaminationExamination Growth velocityGrowth velocity Investigation of children with Investigation of children with

growth retardationgrowth retardation

A) History: to exclude:1 -Social pathology & similar

conditions.2 -Chronic illness (e.g. heart, chest,

renal).3 -Malnutrition.

4 -Drugs (e.g. steroid).

B) Examination:1.Dysmorphic features.2.Disproportion e.g. short limbs.3.Fundus exam (papilledema, optic

atrophy).4.Evidence of systemic disease.5.Assessment of nutritional status.

C) Growth velocity: using percentile growth charts.

D) Investigation of children with D) Investigation of children with growth retardationgrowth retardation::

InvestigationCondition

•CBC, reticulocytes & folate

•Malabsorption / anemia

•Urea, creatinine & electrolytes

•Electrolyte imbalance & renal failure

•HCO3•Renal tubular acidosis

•X-rays for chest & heart

•Asthma or T.B

•ESR, rheumatoid factor•Rheumatoid arthritis

InvestigationInvestigationConditionCondition

•Liver function tests•Hepatitis, chronic liver diseases

•Stool analysis•Giardiasis and other parasites

•Urine culture•Urinary tract infection

•Thyroid function•Hypothyroidism

•Buccal smear for Barr body

•Turner's syndrome

•Ca, Ph, alkaline phosphates

•Vit. D resistant rickets

•Skull x-ray / CT head

•Craniopharyngioma

DISORDEDS OF PUBERTYDISORDEDS OF PUBERTY

Early PubertyEarly Puberty Delayed PubertyDelayed Puberty

A) Early Puberty :

Early puberty is defined as development of secondary sexual characteristics in girls before 7 years and in boys before 9 years. It is commoner in girls.

Characteristics of the precocious puberty Characteristics of the precocious puberty and virilizationand virilization

CharacteristicsTrue precocious puberty

Virilization

Secondary sexual characteristics

PresentPresent (Hirsutism ++)

Breast development (female)

PresentAbsent

CharacteristicsTrue precocious puberty

Virilization

Penis & testisBoth enlargePenis only

Clitoris (female)

Normal development

Excessive enlargement

Spermatogenesis / ovulation

PresentAbsent

Familial history FrequentAbsent

B) Delayed Puberty

• Delayed puberty is defined as no sexual development by the age of 15 years in boys and 14 years in girls.

• Chromosome karyotype is needed to exclude Turner syndrome (in females) and Klinfilter syndrome (in males).

MENTAL RETARDATIONMENTAL RETARDATION

It is a state of impairment of intelligence It is a state of impairment of intelligence from early life due to inadequate from early life due to inadequate mental development throughout the mental development throughout the growth periodgrowth period..

Etiology:Etiology:

In many cases the cause is unknown.In many cases the cause is unknown.

l) Non organicl) Non organic

1.1. Genetic factors: intelligence, like Genetic factors: intelligence, like height and weight, is inherited.height and weight, is inherited.

2.2. Socio-cultural factors: low socio-Socio-cultural factors: low socio-economic state, lack of stimulating economic state, lack of stimulating environment, high blood lead level, environment, high blood lead level, nutritional deficiency, smoking.nutritional deficiency, smoking.

3.3. Emotional disturbancesEmotional disturbances..

II) OrganicII) Organic1) Prenatal:1) Prenatal:A) Genetic:-A) Genetic:- Chromosomal abnormalities:Chromosomal abnormalities: Down's Down's

syndrome, triple X syndrome, syndrome, triple X syndrome, hermaphroditism.hermaphroditism.

Inborn errors of metabolismInborn errors of metabolism: phenylketonuria, : phenylketonuria, galactosemia, cerebral lipidosis.galactosemia, cerebral lipidosis.

Cerebral demyelinating disease, congenital Cerebral demyelinating disease, congenital ectodermosis e.g. neurofibromatosis, tuberus ectodermosis e.g. neurofibromatosis, tuberus sclerosis.sclerosis.

Cranial anomaliesCranial anomalies: primary microcephaly, : primary microcephaly, craniostenosis and congenital hydrocephalus.craniostenosis and congenital hydrocephalus.

B) B) Maternal infections:-Maternal infections:-C) Maternal irradiation or drug intake, C) Maternal irradiation or drug intake, toxemia of pregnancy.toxemia of pregnancy.D) Kernicterus.D) Kernicterus.E) Cretinism.E) Cretinism.

2) Natal2) NatalBirth injuries, anoxia, hypoglycemia, Birth injuries, anoxia, hypoglycemia, hemorrhage.hemorrhage.

33 ( (PostnatalPostnatal

Cerebral infections: Cerebral infections: meningitis, meningitis, encephalitis.encephalitis.

CerebralCerebral trauma.trauma. Cerebro-vascular accidents: Cerebro-vascular accidents: occlusion occlusion

and hemorrhage from congenital defect and hemorrhage from congenital defect or of unknown cause.or of unknown cause.

Post vaccination encephalitis.Post vaccination encephalitis.

MANIFESTATION OF MRMANIFESTATION OF MR

Slow and incomplete maturation:-Slow and incomplete maturation:-

- Delay onset of milestones and - Delay onset of milestones and development retardation.development retardation.

- Delay sphincteric control.- Delay sphincteric control.

- Impaired learning ability and school - Impaired learning ability and school performance.performance.

- Poor social adjustment.- Poor social adjustment.

Degrees of MRDegrees of MRAccording to the Intelligence Quotient According to the Intelligence Quotient

(IQ), mentally retarded children are (IQ), mentally retarded children are classified into:classified into:

DegreeDegree IQIQ PrognosisPrognosis IncidenceIncidence

MildMild 50 – 75 %50 – 75 %EducableEducable 8585 – – 9090% %

ModerateModerate 3535 – – 5050% % TrainableTrainable 55 – – 1010% %

SevereSevere 2020 – – 3535% % NonNon

trainabletrainable

55% %

profoundprofound Below20%Below20%