Mental retardation is known as the impairement of intelligence from early life and inadequate mental development throughout the growth period.It is manifested by impaired learning ability and poor social adjustment.
The intelligence quotient(IQ) is calculated as mental age raported at chronological age multiplied with 100.
Causes that generates mental diseases:
I Prenatal:
a)Genetically determinated causes:
-chromosomal abnormalities:Down syndrome,Cri du chat,fragile X syndrome(sex chromosome).
-neurometabolic disorders:tyrosenemia(aminoacids),isovaleric acedemia(organic acids),carbohydrate(galactosemia)
-neurodegenerative brain disorders
-neurocutaneous disorders:tuberous sclerosis
b)Fetal brain insult
-intrauterine infection:cytomegalovirus,rubella,toxoplasmosis
-drugs:alcohol,phenytoin
-placental insufficiency
-malformations
II Natal:
-hypoxic ischemic injury
-intracranian hemorrhage
III Post natal causes:
-intracranial hemorrhage
-CNS infection
-kernicterus
-metabolic disorders
-poisoning
-psychological:infantil autism
Congenital hypothyroidism and phenylketonuria should not cause mental retardation as they should be diagnosed by routine screening test and treated before causing mental retarsation.
1.Down syndrome-individuals with Down syndrome can have some or all of this characteristics:abnormal small chin,oblique eye fissures with epicnathic skin folds on the inner corner of the eye,poor muscle tone,a flat naal bridge,a single palmar fold,,small oral cavity,short neck,white spots on the iris,congenital heart defects,excessive space between the large toe and second toe.
Down syndrom is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on the 21 chromosome.
2.Cri du chat-is a rare genetic disorder due to a missing part of chromosome 5.The name means cry of the cat and the characteristics are similar to that of a meowing kitten,due to problems with the larynx and nervous system.Others symptoms include:feeding problems,low birth weght,poor growth,severe cognitive(speech0,hyperactivity,aggression,repetitive movements,excesive drooling,constipation.
3.Tyrosinemia-is an error of metabolism,usully inborn,in which the body cannot effectively break down the amino acid.Symptoms include liver and kidney disturbances and mental retardation.
4.Insovaleric acedemia-is a rare autosomal recessive metabolic disorder.A characteristic future is a distinctive odor of sweaty feet.The symptoms become apparentwithin a few days after birth and include poor feeding,vomiting,seizures,lack of energy that can progress to coma.
5.Galactosemia-affects an individual's ability to metabolize the suger galactose properly.
6.Tuberous sclerosis-is a rare multi-system genetic disease that cause benign tumours to grow in the brain and on other vital organs such as kidney,heart,eyes,lungs and skin.
Posts
