Autism spectrum disorder

Neurodevelopmental disorder characterized by persistent deficits in social communication and interaction and restricted, repetitive behaviors and interests, typically recognized in early childhood.

• Common (~1 in 36 children, ~4:1 male) and a major cause of developmental disability. Early identification is crucial because early intervention can markedly improve social and cognitive outcomes. Frequently tested on exams for recognizing red flags and distinguishing ASD from other developmental delays.

• Often noted in toddlers: delayed speech, limited eye contact, not responding to name, and lack of pointing or showing objects (impaired joint attention).
• Children may prefer to play alone, seem uninterested in peers, and exhibit intense fixations (e.g., on specific topics or toys) with distress over minor changes in routine.
• Repetitive behaviors are common (hand flapping, rocking, lining up toys). Some children have intellectual or language impairment and may remain nonverbal, while others (formerly "Asperger") have average intelligence and fluent speech but struggle with social cues.

1. Screen early: use M-CHAT questionnaire at 18 and 24 months (per AAP guidelines). Any failed screen or developmental concern → prompt referral for autism evaluation (do not "wait and see").
2. Obtain a formal audiology (hearing) test in any child with speech delay to exclude hearing loss as a cause.
3. Diagnostic gold standard: comprehensive evaluation by specialists (developmental pediatrician, psychologist) using DSM-5 criteria and standardized observation (ADOS) to confirm ASD.
4. Assess for co-occurring conditions and etiologies: e.g., intellectual disability, language disorder, ADHD, anxiety, or genetic syndromes (fragile X testing) to guide management.

1. Early intensive behavioral therapy (e.g., Applied Behavior Analysis) to improve social and communication skills; parent training and involvement is key.
2. Speech therapy for language development; occupational therapy for sensory integration and daily living skills; specialized education plans (IEP) provide school-based supports.
3. No medication fixes core autism symptoms, but treat comorbid issues: e.g., risperidone or aripiprazole for severe irritability/aggression, stimulants for ADHD symptoms, SSRIs for anxiety or OCD behaviors.

• Mnemonic: 1.5 by 1, 2 by 2 – no single words by ~1.5 years (16 mo) or no 2-word phrases by 2 years are red flags for ASD.
• Fragile X syndrome and tuberous sclerosis are notable genetic conditions associated with a higher risk of ASD.

• No babbling or gesturing (pointing) by 12 months
• No single words by 16 months
• No two-word phrases by 24 months
• Any loss of previously acquired speech or social skills

1. Developmental surveillance at every well-visit; any autism red flag or parental concern → initiate further screening/evaluation immediately.
2. Screen all toddlers at 18 and 24 months with M-CHAT; if screen is positive or concerns arise, refer for comprehensive diagnostic assessment (no delay).
3. Comprehensive eval: perform audiology testing to rule out hearing loss, and a multidisciplinary autism assessment (e.g., ADOS evaluation) to confirm diagnosis per DSM-5 criteria.
4. Upon diagnosis, begin early intervention services (behavioral therapy, speech, OT) as soon as possible – do not wait for additional tests or specialist visits.
5. Provide ongoing support: coordinate an IEP for school, offer family support/resources, and manage co-occurring conditions (e.g., ADHD, anxiety, seizures) with appropriate specialists.

• A 2-year-old with no spoken words, no pointing or waving, and poor eye contact, who spends time lining up toys → Autism spectrum disorder (warrants immediate evaluation).
• An 8-year-old boy with normal language and intelligence but few friends, clumsy social interactions, and an all-consuming interest in one subject → high-functioning ASD (formerly Asperger syndrome).