Prevetable cause of mental retardation

1. Preventable
cause of
Mental Retardation
Guide: Dr. Deepak Dwivedi Dr.Priyank Patel

2. Mental Retardation
Mental retardation is defined as subaverage general
intelligence, manifesting during early developmental period.
The child has diminished learning capacity and does
not adjust well socially.
Now the term mental retardation has been replaced by
Intellectual disability.

3. Intelligence quotient:
It is calculated according to the formula
Mental Age divided by chronological age, multiplied
by 100.

4. Diagnostic criteria for intellectual
disability
A Significantly subaverage intellectual functioning: an IQ
score of 70 or below on an individually administered
IQ test(for infants, a clinical judgment of significantly
subaverage intellectual functioning)
B Concurrent deficits or impairments in present adaptive
functioning (i.e.,the person’s effectiveness in meeting

5. The standards expected for his or her age by his or her
cultural group) in at least two of the following areas:
communication, self-care, home living, social and
interpersonal skills, use of community resources,self-
direction, functionalacademic skills, work,leisure,
health, and safety.
C The onset is before age of 18 years.

6. Grading of intellectual disability:
Mild intellectual disability: IQ 50-55 to 70
Moderate intellectual disability IQ 35-40 to 50-55
Severe intellectual disability IQ 20-25 to 35-40
Profound intellectual disability IQ below 20-25
Intellectual disability, Severity unspecified, when there is
strong presumption of intellectual disability but the person’s
intelligence is untestable by standard tests.

7. Causes of Intellectual disability
Prenatal factor:
Aminoacidopathies: Organic acidemia, Phenylketonuria,
hompcystinuria, histidinemia, organic aciduria
Carbohydrate disorder: Glycogen storage disorder, glucose
transport defect, galactosemia
Chromosomal disorder: Down syndrome, fragile X syndrome,
Klinefelter syndrome
Iodine deficiency

8. Neuroectodermal dysplasia: Tuberous sclerosis
Developmental defects: Microcephaly, craniostenosis,
porencephaly, cerebral migration defect
Maternal factor:
Use of teratogens in first triamaster of pregnancy
Intrauterine infection

9. Placental deficiency, toxemia of pregnancy, antepartum
hemorrage
Radiation during prenancy
Natal factor:
Birth injury
Hypoxic ischemic encephalopathy
Intracerebral hemorrhage

10. Post natal factor:
Infection of central nervous system
Head injury
Thrombosis of cerebral vessels
Post-vaccinal encephalopathies
Kernicterus, hypoglycemia
Hypoxia, hypothyroidism
Malnutrition , child abuse
autism

11. Development screening
Phatak’s Baroda screening test:
This is India’s best known development testing
system but meant to used by child psychologist rather
than physician.
Denver development screening test:
It has 4 domain i.e. gross motor, fine motor
adaptive, language and personal social behavior

12. Trivandrum development screening chart:
it is simplified adaptation of Baroda development
screening system.
applicable to children up to 2 year of age
useful as a mass screening test.
•Goodenough-Harris drawing test
•Clinical adaptive test and clinical linguistic and auditory
milestone scale (CAT/CLAMS)

13. Definitive test
Bayley scale for infant development II
it is the most commonly used scale.
usually takes 30-60 min to assess
Assesses language behavior, fine motor,gross motor,
and problem solving skill, provides mental
development index and psychomotor development
index

14. Wechsler intelligence scale for children IV:
The most commonly used psychological test for children
>3 year of age
Assesses verbal and performance skill
Provide full scale IQ and indices of verbal
comprehension perceptual reasoning workig memory
and processing speed
Other test like
Stanford-Binet intelligence scale 5th edition

15. Factors affecting Development along with
preventble cause of intellectual disability
Prenatal factors:
•Genetic factors: Intelligence of parents has direct
correlation on the final IQ of the child.
There are several genetic causes for development
Delay and subsequent mental retardation.

16. (1)Neuro-Metabolic diseases:
There are few neuro metabolic disorder which if
diagnosed and treated timely can be prevent
developmental delay in child.

17. (a)Phenylketonuria:
This disorder is caused by deficiency of enzyme phenyl
alanine hydroxylase.
The affected infant is normal at birth.
Profound mental retardation develop gradually if the
infant remains untreated.
Vomiting may be an early symptom.

19. The infant are lighter in their complexion than unaffected
sibling.
Neurological symptom include seizure, spasticity, hyperreflexia,
and tremor.
Microcephaly ,
Prominent maxillae with widely spaced teeth.
Growth retardation

20. Diagnosis:
Quantitative measurement of plasma phenylalanine
concentration.
Treatment:
Should be treated with a phenyl restricted diet.
Formula low or free of phenyalanine ar e commercially
available.

21. (b)Galactosemia:
Denotes elevated level of galactose in blood.
caused mainly due to deficiency of
(i) galactose-1-phosphate uridyl transferase
(ii)galactokinase
(iii) uridine diphosphate galactose-4-epimerase
Clinacal feature:
Jaundice
hepatomegaly

23. Vomiting
Hypoglycemia
Seizure
Lethargy, irritability
Poor weight gain
Hepatic failure
Splenomegaly
Mental retardation
Ascitis

25. Diagnosis:
The preliminary diagnosis is made by demonstrating a
reducing substance in several urine specimens collected while
the patient is milk or any other formula containing lactose.
For confirmation quantitative measurement can be done
Treatment:
Non lactose containing diet

26. Hypothyroidism
All inborn error of metabolism
should be diagnosed at the earliest
and should be treated.

27. Maternal factor:
(i)Maternal malnutrition:
deficiency of various micronutrient can
adversely affect development of fetus and later on can
have influence on infant development
(ii)Exposure to drug and toxin:
use of alcohol during pregnancy can affect
mental development of infant.

28. Fetal Alcohol syndrome
Occurs because of high level of alcohol ingestion during
pregnancy.
Clinical feature;
Prenatal onset and persistence of growth deficiency
facial abnormality including short palpebral fissure,
epicanthal fold, maxillary hypoplasia,

29. micrognathia, smooth philtrum, smooth upper lip
Cardiac defect primarily septal defect
Minor joint and limb abnormalities
Mental retardation
Treatment:
No specific therapy exists
Prevention:
By eliminating alcohol intake after conception.

31. Maternal smoking causes decreases in birth weight. Along
with this it also cause defect in brain, heart and face,
Use of cocaine and opioid during pregnancy can cause
serious problem in fetus.
Valproic acid can have severe defects in child
Maternal exposure to radiation also have deleterious effect
upon fetal developments

32. Maternal diseases and infection :
Pregnancy induced hypertension
Hypothyroidism
Feto-placental insufficiency due to any cause
Acquired infection e.g. toxoplasmosis,
Rubella, CMV, herpes, Chorio-amniotis

33. (iii)Maternal infection:
Among various infection one of the most imp. Is
TORCH infection
Toxoplasmosis:
caused by Toxoplasma gondii, an obligate
intracellular protozoan.
There is a wide variety of manifestation:

34. May lead to hydrops foetalis and perinatal death
Classical triad is
Chorioretinitis
Cerebral calcification
Hydrocephalus
Diagnosis:
diagnosis can be done by culture or serological tests

36. Treatment:
Pyrimethamine
Sulfadiazine

37. Cytomegalo virus infection
Congenital infection can manifest as
IUGR
Prematurity
Hepatosplenomagaly
Jaundice
blueberry muffin like rash
Thrombocytopenia
Microcephaly
intracranial calcification

40. Diagnosis:
definitive method of diagnosis is virus isolation or
demonstration of CMV DNA by PCR.
Treatment:
Ganciclovir, foscarnet, cidofovir

41. Neonatal Risk factor
Intrauterine growth restriction:
Adversely affect development
Prematurity:
Chances of developmental impairment
increases with prematurity. More the child is premature
more will be the risk. Mainly because of complications like
intracranial bleed, white matter injury, hypoxia, hyper-
bilirubinemia and hypoglycemia

42. Various metabolic derangement can affect child
development like
Hypoglycemia
Hypocalcemia
Hyperbilirubinemia
Hyperthermia

43. Perinatal asphyxia:
Studies have indicated that over 40%
of survivor of significant asphyxia suffer from
major neurocognitive disabilities.
Incidence can be decreased by Institutional delivery, proper
resuscitation, early stimulation therapy

44. Post natal factors :
Infant and child nutrition:
Early growth faltering (<24 month ) seems
to be more detrimental to childhood development.
Calorie deficeincy associated with multiple micronutrient
and vitamins like zinc, vitamin A, B12, D, E contribute to
developmental impairment.

45. Iron deficiency
Associated with delayed brain maturation, poorer
cognitive, motor and social emotional development
Iodine deficiency
it can lead to congenital hypothyroidism and
irreversible mental retardation, making it the most common
preventable cause of mental retardation.
Infectious disease
Diarrhoea, malaria, other parasitic infection and HIV

46. Environmental toxins
Like lead, arsenic, pesticide, mercury, and polycyclic aromatic
hydrocarbons
Exposure may be prenatally through maternal exposure or
postnatally through breast milk, food, water, house dust, soil

47. Acquired insult to brains:
traumatic or infectious insult like meningitis,
encephalitis, cerebral malaria and other factor like near
drowning, trauma particularly during early years of life can
have a permanent adverse effect on brain development.
Associated impairment
impairment particularly those involving sensory inputs
from the eyes or ears can have a significant impact on
attainment of milestone.`

48. Psychosocial factor
Parenting:
cognitive stimulation, caregiver’s sensitivity and affection
have important role in child development.
Higher level of maternal warmth and responsiveness are
associated with higher cognitive ability and reduced level of
behavioral problems in young children.

49. Poverty:
this is possibly the most common underlying
factor for impaired child development.
Lack of stimulation:
Social and emotional deprivation and lack of
adequate interaction and stimulation is an important cause
of developmental impairment.

50. Violence and abuse:
Domestic and community violence can have
profound psychological effect on the child.
Maternal depression:
it is negatively associated with child
development.
Institutionlization:
Institutional care like orphanages during
early life increases the risk of poor growth, ill health,
attachment disorder

51. Protective factor:
Breastfeeding:
have protective and promotive effect on child
development.
Maternal education:
has protective effect

52. Congenital Hypothyroidism
•It is the most common preventable cause of mental
retardation.
•Iodine deficiency is the most common cause of congenital
hypothyroidism.

53. Clinical feature:
Most infant with congenital hypothyroidism are
asymptomatic at birth due to transplacental passage of
maternal T4.
Despite having maternal thyroxine infant have low level
of serum T4 and elevated TSH.
Twice common in girls than boys

54. Birth weight and Height are normal but head size may be
slightly increased.
Prolongation of physiologic jaundice may be the earliest
sign.
Feeding difficulties especially sluggishness, lack of
interest, somnolence and choking spell during nursing
are often present.
Respiratory difficulty due to large tongue
Poor appetite, constipation
Umbilical hernia

55. Temperature is subnormal.
Large abdomen
Edema of the genital and extremities
Pulse is slow, heart murmur, cardiomegaly, pericardial effusion
Macrocytic anaemia
Congenital anomaly mostly cardiac
Hearing loss
Widely opened anterior and posterior fontenelle
Neck short thick
Hands are broad and fingers are short

56. Myxedema mainly in skin of eyelids, the back of the hands,
and external genitalia.
Development is delayed
Hypotonia

58. Lab diagnosis:
For Newborn Screening blood is obtained between 2 and
5 day of life by heel-prick.
Serum level of T4 or free T4 are low; serum level of T3 may be
normal and not helpful in diagnosis.
If the defect is primarily in thyroid level TSH are elevated.

59. Radiological:
• Retardation of osseous development can be seen.
• The distal femoral epiphysis, normally present at
birth, is often absent.
• the epiphysis often have multiple foci of ossification.
• Deformity of T12,L1, L2 is common.
Electrocardiography
may show low voltage P and T wave with diminished

60. Amplitude of QRS complex and suggest poor left ventricular
function.
Echocariography:
Pericardial effusion may be seen.
EEG:
often shows low voltage
MRI:
normal

61. Treatment:
Levothyroxine given orally is treatment of choice.
the recommended initial starting dose is 10-
15ug/kg/day
Neonate with more severe hypothyroidism should be
started at the higher end of dosage range.
Thyroid function test should be done at recommended
interval usually monthly in first 6 month of age then at
2- 3 month interval.

62. Thyroid replacement should be stopped for one month at
the age of 3 yr in suspected transient hypothyroidism.
Treatment may be discontinued in the absence of persistent
Abnormality on investigation and normal level of thyroid
hormone.

63. Prognosis:
Early diagnosis and adequate treatment from the first
weeks of life result in normal linear growth and
intelligence.
Most severely affected children can have retarded
skeletal maturation and have reduced IQ and can have
other neurological consequences like hypotonia,
hypertonia, incoordination, short attention span and
speech problem

64. Prevention and control:
Iodine disorder are best prevented as treatment
is usually ineffective. Iodinated salt and iodized oil are
highly efficacious in preventing iodine deficiency.
The National Goiter Control Program of the Ministry
of Health in India began in 1962 with establishment of
iodination plant.

65. Prevention of Mental Retardation
Examples of primary program to prevent intellectual
disability include:
Increasing the public’s awareness of the adverse effect of
alcohol and other drugs of abuse on the fetus.
Preventing teen pregnancy and promoting early prenatal care
Preventing Traumatic injury: Encouraging the use of guards
and railing to prevent fall and other avoidable injuries in the

66. Home ; using appropriate seat restraints when driving and
wearing a safety helmet when biking ; teaching firearm safety
Preventing Poisoning: Teaching parents about locking up
medications and potential poison.
Implementing immunization programs to reduce the risk of
intellectual disability due to encephalitis, meningitis and
congenital infection.

67. Newborn hearing screening programs.