AUTISM

AUTISM - Brigid Barry McKenna, MD
BASICS
DESCRIPTION
• Autism is a pervasive developmental disorder of early childhood, characterized by
- Severe impairment in effective social skills
- Absent or impaired communication skills
- Repetitive and/or stereotyped activities and interests, especially inanimate objects
• System(s) Affected: Nervous
• Synonym(s): Early infantile autism; Childhood autism; Kanner autism; Pervasive developmental disorder
ALERT
Pediatric Considerations
Onset seen only in children 3 years.
Pregnancy Considerations
May be increased risk of autism with complications of pregnancy, labor, and delivery
EPIDEMIOLOGY
• Predominant age: Onset prior to age 3 years, but generally abnormal development is apparent well before
• Predominant sex: Male > Female (4:1)
Incidence
Estimated 1/500 children (1)
RISK FACTORS
• Certain medical conditions, including fragile X syndrome, tuberous sclerosis, congenital rubella syndrome, and untreated phenylketonuria (PKU)
• Sibling with autism
Genetics
• High concordance in monozygotic twins
• Increased recurrence risk (3-7%) in subsequent siblings (2)
ETIOLOGY
• No single cause has been identified. It is generally believed that autism is caused by abnormalities in brain structure or function. Research continues to investigate the links between heredity, genetics, and medical problems.
• No documented scientific evidence exists that proves vaccines (specifically thimerosal preservative) cause autism.
ASSOCIATED CONDITIONS
• Mental retardation (common)
• Attention deficit/hyperactivity disorder (common)
• PKU, tuberous sclerosis, and fragile X syndrome (Rare)
• Anxiety
• Depression
• Obsessional behavior
• Seizures (common)


DIAGNOSIS
SIGNS AND SYMPTOMS
• Impairment in social interaction
- Poor eye contact (1)
- Does not seem to know how to play with toys (1)
- Does not smile (1)
- Loss of social skills (1)
• Communication impairment
- Does not babble, point, or make meaningful gestures by 1 year of age (1)
- Does not speak one word by 16 months (1)
- Does not combine 2 words by 2 years (1)
- Does not respond to name (1)
• Repetitive and stereotyped patterns of behavior
- Excessively lines up toys or other objects (1)
- Unusually attached to one particular toy or object (1)
- Odd movements (toe walking) (1)
History
• Pregnancy, neonatal, and developmental history
• Seizure disorder
• Family history of autism or any genetic disorders
Physical Exam
Macrocephaly in 25% (2)
TESTS
• Screening tests
- Checklist for Autism in Toddlers (CHAT) is used to screen for autism at 18 months of age
- Modified Checklist for Autism in Toddlers (M-CHAT) to screen for autism at 24 months
- The Screening Tool for Autism in Two-Year-Olds (STAT)
- Autism Screening Questionnaire has been used with children age 4 years and older.
• Diagnostic testing
- Evaluation by multidisciplinary team that includes a psychiatrist, a neurologist, a psychologist, a speech therapist, and other autism specialists
- Childhood Autism Rating Scale (CARS)
- Autism Diagnosis Interview Revised (ADI-R)
- Autism Diagnostic Observation Schedule (ADOS-G)
- Intellectual level needs to be established and monitored, as it is one of the best measures of prognosis.
Lab
• Lead screening
• PKU screening
• Chromosomal analysis (fragile X, others)
Imaging
MRI could be useful in ruling out associated conditions.
Diagnostic Procedures/Surgery
EEG, as autistic children have a markedly higher incidence of epilepsy, which increases with age
DIFFERENTIAL DIAGNOSIS
• Other mental and central nervous system disorders
- Schizophrenia
- Elective mutism
- Language disorder
- Mental retardation
- Stereotyped movement disorder
• Other pervasive developmental disorders
- Rett disorder
- Childhood disintegrative disorder
- Asperger disorder
TREATMENT
GENERAL MEASURES
• Comprehensive structured educational programming of a sustained and intensive design, most commonly applied behavioral analysis therapy (ABA)
• There is currently no cure for autism. Early diagnosis and initiation of multidisciplinary intervention will help enhance functioning in later life.
• Early Intervention for ages 3 and under
• School-based special education
• Find alternative methods of communication
- Sign language
- Picture exchange communication system (PECS)
• Consider consults
- Ophthalmology
- Otolaryngology
- Metabolic testing
- Genetic screening for Fragile X
- Wood's lamp exam (for tuberous sclerosis)
• Parent support groups and respite programs
Diet
Gluten- and casein-free diets show some reduction in autistic traits; however, large scale, good quality RCTs are needed. (3)
Activity
As tolerated by the child
SPECIAL THERAPY
Complementary and Alternative Medicine
Vitamin B6-Magnesium has shown some improvement in speech and language; however, due to the small number of studies and small sample size, no recommendations exist for its use. (4)
MEDICATION (DRUGS)
• Stimulant medications such as methylphenidate are efficacious in treating concomitant symptoms of attention deficit disorder, such as impulsiveness, hyperactivity, and inattention; however, the magnitude of response is less than in typically developing children, and adverse effects are more frequent. (5)[A]
• Fluvoxamine, an SSRI, has shown some help in reducing ritualistic behavior and improving mood and language skills. (6)[B]
• Risperidone (Risperdal) has been shown to be effective for short-term treatment of tantrums, aggression, and self-injurious behavior. Improvements in stereotyped behavior and hyperactivity have also been noted. Given the risk of serious side effects, it should be reserved for moderate to severe behavioral problems. (7)[A]
• Precautions
- Risperidone may be associated with hyperglycemia and ketoacidosis. Risperidone may cause neuroleptic malignant syndrome and extrapyramidal reactions. (7)
FOLLOW-UP
PROGNOSIS
• Those who begin treatment at a young age have significantly better outcomes.
• Prognosis is closely related to initial intellectual abilities, with only 20% functioning above the mentally retarded level.
• Communicative language development before 5 years of age is also associated with a better outcome.
• The general expected course is for a life-long need for supervised structured care.
COMPLICATIONS
• Increasing incidents of seizure disorders in up to 1 in 4 children with autism (1)
• Increased risk for physical and sexual abuse in autistic children
PATIENT MONITORING
• Constant by caregivers
• As indicated by physician, prescribed medical management
• Intellectual and language testing every 2 years in childhood
REFERENCES
1. Strock M. Autism spectrum disorders (pervasive developmental disorders). NIH Publication No. NIH-04-5511. Bethesda, MD: National Institute of Mental Health, National Institutes of Health, U.S. Department of Health and Human Services; [updated 2004 April; cited 2006 Mar 2]. Available from: http://www.nimh.nih.gov/publicat/autism.cfm
2. Committee on Children with Disabilities. The Pediatrician's role in the diagnosis and management of autistic spectrum disorder in children. Pediatrics. 2001;107:1221-1226.
3. Milward C, Ferriter M, Calver S, et al. Gluten- and casein-free diets for autistic spectrum disorder. Cochrane Database of Systematic Reviews. 1,2006.
4. Nye C, Brice A. Combined vitamin B6-magnesium treatment in autism spectrum disorder. Cochrane Database of Systemic Reviews. 1,2006.
5. Research Units on Pediatric Psychopharmacology Autism Network. Randomized, controlled, crossover trial of methylphenidate in pervasive developmental disorders with hyperactivity. Arch Gen Psychiatry. 2005;62:1266-1272.
6. McDougle CJ, Naylor ST, Cohen DJ, et al. A double-blind, placebo-controlled study of fluvoxamine in adults with autistic disorder. Arch Gen Psychiatry. 1996;53:1001-1008.
7. Research Units on Pediatric Psychopharmacology Autism Network. Risperidone in children with autism and serious behavioral problems. N Eng J Med. 2002;347:314-321.
MISCELLANEOUS
See also: Anxiety; Attention Deficit/Hyperactivity Disorder; Depression; Fragile X Syndrome; Mental Retardation; Schizophrenia; Seizure Disorders