Mental retardation

Def : Inadequate mental development & social adaptation < 18 yrs.

Causes:

1- Pre-natal causes:
a- Maternal causes.
1- Placental insufficiency.
2- Premature labour.
3- Medications
4- Poisons.
5- Radiation.
6- Congenital infections.
b- Fetal causes:
1- Genetic causes:
* Chromosomal disorders e.g., Down.
* Familial MR.
* Congenital hypothyroidism.
2- Inborn errors of metabolism:
* Phenylketonuria.
* Galactosemia.
3- Cranial abnormalities:
* Microcephaly.
* Craniosynostosis.
* Hydrocephalus.
2- Natal causes:
* Birth trauma I.C. Hge Anoxia & asphyxia.
3- Post-natal causes: C P K
- Cerebral trauma.
- Cerebral infections.
- Cerebro – vascular accidents.
- Poisoning e.g., CO
- Post immunization encephalitis.
- Kernicterus.

C/P :

1- Developmental → delayed milestones.
2- Educational → failure of benefit from – instructns. – experience.
3- Social→ failure of social maturation.

Diagnosis:

 by I.Q = Mental age / Chronological age X 100
Grading: - Mild : ( Moron ) → 51 : 75 %
- Moderate : ( Imbecile ) → 21 : 50 %
- Sever : < 20 %

Diagnostic criteria:

1- IQ. < 75%
2- Age of onset of defect < 18 yrs.
3- Defective adaptation to surrounding environment. 

Investigations:

1- Karyotype → in chromosomal abnormalities.
2- Neonatal screening → in phenylketonuria.
3- X-ray C.T. → in microcephaly & craniostenosis .
4- Hypothyroidism.

Mangement:

1- Prophylaxis → best management.
2- Early diagnosis → complete cure in some patients "curable MR.".
a- Cretinism – thyroxin.
b- Hydrocephalus – shunt operation.
c- Craniosynostosis – craniotomy.
d- Phenylketonuria – diet free from it.
e- Galactosemia – lactoase free formula.
3- Well established cases → ( treatment according To degree ).
- Mild degree (Moron) → Educable & trainable.
Special education needed for optimal develop.
- Moderate degree ( lmbecile ) → non educable.
Occupational training i only management.
- Severe degree ( Idiot ) : → Non educable & Non Trainable.
- If there is convulsions: anticonvusant drugs.