Autism

Autism



Susan L. Hyman, MD



Basic Information



Definition


A developmental disorder characterized by a qualitative impairment in social reciprocity, a qualitative impairment in communication, and repetitive behaviors. The Autism Spectrum includes five disorders:


• Autism: stringent criteria are met with symptoms in all three areas listed above.

• Asperger’s syndrome: defined by normal early language, normal cognition, and symptoms related to social reciprocity and restricted interests/repetitive behaviors.

• Rett syndrome: found primarily in girls with loss of language and hand use.

• Disintegrative disorder: symptoms start later in childhood and extend to daily living and motor skills.

• Pervasive developmental disorder—not otherwise specified: when the criteria for the other disorders in this category are not met.


Synonyms



Autism spectrum disorders (ASDs)

Pervasive developmental disorders (PDDs)


ICD-9-CM Codes



299 Pervasive developmental disorders

299.0 Autism

299.1 Disintegrative disorder

299.8 Asperger’s syndrome

330.8 Rett syndrome


Epidemiology & Demographics



• This condition may affect as many as 1 in 166 people; older studies cite numbers of 4 to 5 in 10,000.
image Question of increasing prevalence versus better detection and broader definition

image Autism may have prevalence of 40:10,000; PDD/ASD overall may be as much as 60:10,000

• Male predominance of 4:1 for autistic disorder

• Up to 70% of people with autism also have mental retardation.
image Asperger’s syndrome defined by IQ in typical range.


Clinical Presentation



• Infancy: decreased eye contact, language delays, acts as if deaf, repetitive behaviors
image One fourth to one third of autistic children lose language skills in the second year of life.

• Early childhood: insistence on routine, lack of pretend play, repetitive behaviors

• Later childhood/adolescence: problems with peer interactions

• Generally nondysmorphic

• May be associated with tuberous sclerosis, fragile X syndrome
image Less frequent comorbidity with Down syndrome, Möbius’ syndrome, and Joubert’s syndrome, among others

image Comorbidity with neurologic symptoms like seizures (25%) or tics (9%) common

• May have clumsiness, mild hypotonia


Etiology



• The cause is unknown.

• The evidence for a genetic etiology is strong.
image Concordance in identical twins is greater than 60% for autism and greater than 90% if symptoms, but not the complete disorder, are included.

image Recurrence risk is 100 times the general population for families with one child with autism.

• Epidemiologic and basic science evidence does not support either measles-mumps-rubella vaccination or mercury toxicity from thimerosal as causative.
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Jun 19, 2016 | Posted by in PEDIATRICS | Comments Off on Autism

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