Autism spectrum disorder: Clinical sciences

Autism spectrum disorder, or ASD for short, is a neurodevelopmental condition characterized by deficits in social communication as well as patterns of restricted and repetitive behavior. Autism is considered a spectrum disorder due to the wide variability in the traits, behaviors, and degree of disability that individuals can experience. Autism is thought to be caused by a combination of genetic and environmental factors that result in altered neural connectivity and atypical brain development. Children with autism who are identified early and receive timely evaluation are more likely to benefit from intervention services, which ensure better developmental outcomes, including improvements in communication and functional skills.

Now, when a pediatric patient presents with a chief concern suggesting autism spectrum disorder, your first step is to obtain a focused history and physical exam. Caregivers commonly report that their child appears socially disengaged and does not communicate or interact with others in typical ways. For instance, many caregivers notice that their child has poor eye contact. The child may also perform repetitive movements, like hand flapping or body rocking, as a means of self-soothing. They may also lack flexibility and adaptability, so disrupted routines or unexpected changes often cause significant distress.

Risk factors for ASD include prematurity, low birth weight, and certain genetic conditions, such as fragile X syndrome, which is the most common genetic cause, and Rett syndrome. It’s also important to note that autism is highly inheritable, so be sure to ask if there’s a family history of ASD. Although the physical exam is often unremarkable, some patients may have macrocephaly or low weight-for-age.

Now, here’s your first clinical pearl! ASD is frequently underdiagnosed or diagnosed late, especially in biologically female children, ethnic minorities, such as African American and Hispanic children, as well as in those with low socioeconomic status and children from non-English-speaking families. For this reason, pay close attention when any social, behavioral, or developmental concerns arise in these groups.

If you see these history and exam findings, your next step is to administer a developmental screening tool that includes specific questions about ASD. These questionnaires rely on caregiver reports of the child’s observed behaviors, and results can identify various types of developmental delay. Screening results that suggest a social communication delay, with or without cognitive, language, or motor delays, should lead you to suspect ASD.

Here’s a clinical pearl to keep in mind! Patients are routinely screened for ASD during the 18- and 24-month well-child visits. A toddler with a positive autism screen may benefit from an additional evaluation for ASD and other developmental delays, even if the caregivers’ history reveals no concerns.

Once you suspect ASD, your next step is to arrange for a comprehensive neurodevelopmental evaluation. This evaluation will determine whether the patient meets the diagnostic criteria for autism spectrum disorder. It will also assess developmental strengths and weaknesses and identify specific needs that can be addressed through personalized interventions. The comprehensive neurodevelopmental evaluation includes a developmental and behavioral history; direct observation of behavior; cognitive, language, and motor testing; and assessments of vision and hearing.

Now, the comprehensive neurodevelopmental evaluation will likely demonstrate deficits in social communication and interaction, as well as restricted and repetitive patterns of behavior and interests. Moreover, ASD-specific social communication characteristics include difficulties with both verbal and nonverbal language. Individuals with autism often display limited social-emotional reciprocity, which manifests as difficulty maintaining conversations due to a lack of interest, poor insight into other people’s thoughts and feelings, poor eye contact, speaking in a monotone voice without inflections, and having unusual facial expressions.