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, , , , , ,*,Mental Retardation,1,Contents :,Definition,Prevalence,Classification,Causes,Clinical Evaluation,Investigation,Management,2,Definition,Mental Retardation is defined statistically as tested,cognitive performance that is two standard deviation below the mean of the general population,( roughly below the 3,rd,percentile ),3,The Classical definition comprises 3 components :,1- subaverage intellectual function .,2- that result from an injury , disease or abnormality before the age of 18 years .,3- resulting in impaired ability to adapt to the environment .,4,Prevalence :,Mental retardation is present in about 2 to 3% of the population,.,5,AAMR Classification Scheme,IQ classification:,I.Q.(intelligence quotient) is 100; normal ranges from 90 to 110,1-Border line IQ 70-80 ,2-mild MR IQ 55-70 ,3-moderate MR IQ 40-55 ,4-sever MR IQ 25-40 ,5-profound MR IQ below 25 ,6,7,Etiology,Unknown “ 30-40 % “,Genetic “ 5% “,Early embryonic ( prenatal ) “ 30% “,Prematurity, IUGR (,perinatal,) “ 10 % “,Acquired medical condition (trauma , infection .) “ 5% “,Environment “ 5-20% “,8,Etiology classification :,Prenatal,Perinatal,Postnatal,9,Prenatal causes :,Genetic Disorders :,Fragile X syndrome FXS :,most common cause .,Klinefelter,syndrome :,male with extra x chromosome,47,XXY,Down syndrome :,Meabolic,disorders:,PKU,Tay-sachs,Galactosemia,Skin disorders :,neurofibromatosis and,Tubererous,sclerosis .,Prader-Willi,Syndrom,:,Endocrine :,hypothyroidism,10,Fragile X syndrome (FXS),Is the commonest cause of MR.,The incidence has been estimated at approximately 1 in 1,500 males and 1 in 2,500 females,.,Mutation of a gene on the long arm of the X chromosome is responsible for FXS and involves instability of,trinucleotide,repeat sequence .,DNA,-,analysis of the FMR-I gene is the best way to diagnose which is usually done on lymphocytes.,11,Fragile X syndrome (FXS),cont,.,C/P: phenotype ,Large ears , Large testes (testicular volume30 ml in adults) , Plantar crease , Hyperextensible joints , Simian crease,Broad forehead, Increased hand width, Increased hand length , Elongated face, High arched palate ,Mitral valve prolapse , Hypotonia , Hernia, Double jointed thumbs , Scoliosis and Flat feet,12,Fragile X syndrome (FXS),cont,.,C/P: ,NEUROCOGNITIVE,Mental retardation , Hyperactivity , Attentional problems , Language delays , Hand flapping , Hand biting , Irritability , Perseveration , Excessive temper tantrums Gaze avoidance , Sensory aversion , Self-stimulatory behavior and Autism,13,14,15,Cranial,Malformations :,Anencephaly :,microcephaly,:,Hydrocephaly :,16,Congenital Factors :,Maternal :,Rubella , congent. Syphilis & Rh incompitability,Toxins :,drugs , fetal alcohol,syndrom,.,17,Perinatal Causes :,Low Bwt :,premature , teen pregnancy , poor nutrition .,21 % with MR,Birth Anoxia,:,breech presentation , knotted umbilical cord.,18,Postnatal Causes :,Child abuse and neglect :,Traumatic brain injury :,Infection :,meningitis and encephalitis,Nutritional deficiencies :,Cultural and familial :,19,Clinical Evaluation,Complete History :,Examination :,20,History,complete and detailed history,complete systemic review,surgical history :,trauma , accidents,medical illnesses :,hospitalization , general heath,pregnancy history :,maternal age , parity , infections.,birth :,type , wt . GA ,complications , apgar score,Postnatal :,incubator , ventilator , disease .,21,History (cont.),drugs:,mother and child,developmental Hx :,mile stones , loss it , speech .,educational Hx :,schooling , IQ tests,behavioral Hx :,skills , attention , activity,family Hx :,consanguinity , inherited ds .,social Hx :,22,Examination,complete and detailed examination,Growth parameters :,Dysmorphic features :,CNS examination :,Other system and skin exam :,IQ tests :,Developmental testing :,23,Investigations, there is no specific investigation for MR but good hx and physical examination guide us toward the proper one ,DNA analysis:,chromosomes,FISH probes:,Prader-willi,wiliams,cri du chat syndrom,Metabolic labs:,plasma a.a. , urine organic a. ,TFT , ck,Imaging :,brain MRI , CT , skeleton films,Psychological Assesment:,Electrophysiology :,EEG , auditory & visual evoked potentials,24,When to do the investigations?,Cytogenetic studies if:,Microcephaly,Multiple,(,even minor,),somatic anomalies,Family history of mental retardation,Family history of fetal loss,IQ 50,Skin pigment anomalies,(,mosaicism,),Suspected contiguous gene syndromes,(,e,.,g,.,Prader,-,Willi,Angelman, Smith,-,Magenis,),25,Metabolic studies if :,Episodic vomiting or lethargy,Poor growth,Seizures,Unusual body odors,Somatic evidence of storage disease,Loss or plateau of developmental skills,Movement disorder,(,choreoathetosis,dystonia, ataxia,),Sensory loss,(,especially retinal abnormality,),Acquired,cutaneous,disorders,MRI of the brain if :,Cerebral palsy or motor asymmetry,Abnormal head size or shape,Craniofacial malformation,Loss or plateau of developmental skills,Multiple somatic anomalies,Neurocutaneous,findings,Seizures,IQ 50,26,Management of MR, there is no specific Rx for MR ,General rules :,-Identify the cause then initiate a comprehensive plan,-Special educator , Language , behavioral and occupational therapists,-Special school programs,-Community services,27,
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