Autism

Chapter 26 Autism



Anne M. Meduri, MD




Medical Knowledge and Patient Care



Background and Definitions


Autism is a neurologically based developmental disorder characterized by significant impairment in communication skills and social interactions, along with repetitive and restrictive patterns of behavior. The diagnosis of autism spectrum disorders (ASD) has been increasing at an alarming rate, with the best estimate of the current prevalence at approximately 6 per 1,000 or 1 in 150. Based on a survey completed in 2004, 44% of primary care physicians (PCPs) reported caring for at least 10 children with ASD. It is vitally important therefore that all physicians have awareness and knowledge to better recognize and manage patients with ASD.


Historically, autism was considered a form of schizophrenia. In 1943 Dr. Leo Kanner, a psychiatrist at Johns Hopkins University, described a group of children with extreme aloofness and indifference to other people. These children exhibited features of the disorder from very early in life. In 1944, Dr. Hans Asperger, an Austrian pediatrician, described a similar group of children; however, their cognitive and verbal skills were much higher. The current criteria for diagnosis of autistic disorder (AD) and Asperger syndrome (AS) can be found in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM-IV-TR). ASD also includes pervasive developmental disorder–not otherwise specified (PDD-NOS), in which there are subthreshold characteristics that do not meet the full criteria for AD or AS.



Etiology


The etiology of ASD is not yet fully known. It is most likely multifactorial. There appears to be a strong genetic component but with great complexity involving multiple genes. Estimated recurrence risk is approximately 6% when there is an older sibling with ASD. The rate is even higher if there are two children in the family with ASD. There may also be environmental factors, including advanced paternal and maternal age. There is a male predominance, which suggests a gene located on the X chromosome. Neurogenetic syndromes represent a small percentage of ASD. This includes fragile X syndrome, neurocutaneous disorders, fetal alcohol syndrome, and Rett syndrome. Recent research efforts have been focused on the neurobiologic basis of ASD. Differences exist in brain growth and organization when comparing persons with ASD with their typically developing peers. Children with autism often have an average to below-average head circumference at birth, with acceleration noted in the first year of life.



Clinical Manifestations


Speech delay is often the first deficit noted by parents and brought to the attention of the PCP. This may occur between 15 and 18 months of age. It is important to sort out which children are simply speech delayed. One way to do this is by considering if children are trying to compensate for their lack of verbal skills by communicating via gestures or pointing. Higher-functioning ASD children or those with Aspergers syndrome may have many words that they use; however, they might use them solely for labeling and without communicative intent. These children often have what is described as “scripted” speech, reciting volumes of lines from movies and television shows. Children with ASD frequently have echolalia, where they repeat portions of another person’s speech. It is important to recognize that typically developing children may go through a period of echolalia. In autism, however, the echolalia persists as they grow older. Very early signs of prespeech deficits can include lack of appropriate gaze, lack of reciprocal vocalizing between infant and parent, lack of response to name, and limited prespeech gestures such as pointing and waving. A history of regression or loss of language skills should be carefully investigated by the PCP because this is reported in approximately 25% of children with ASD.


Deficits in social skills are another key feature of ASD; however, these deficits are not always recognized or reported by the parents. They may describe their babies as very “low maintenance,” entertaining themselves for long periods of time or remaining in their cribs without needing attention. They often do not respond or localize when their name is called, and parents will frequently express a concern about hearing. When given the opportunity to be around other children, those with ASD are often on the perimeter of activity, unaware and uninterested in what the rest of the group is doing. These social differences become more apparent as children start to participate in group activities such as play groups, preschools, and sports.


Along with assessing speech and social skills, it is important to inquire about and observe a child’s play skills and behavior. Children with ASD have difficulty with imaginative or pretend play. They may become preoccupied with parts of toys and play with them in a repetitive fashion, such as stacking or lining up. They are resistant to any type of imitative tasks. They have intense interest in simple objects, such as pieces of string or spinning fans. They frequently exhibit repetitive, nonfunctional behaviors known as stereotypies. These can include hand flapping, finger flicking, jumping, and spinning. Although these behaviors are not harmful, they can impede development of more appropriate cognitive, communication, and social skills.

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  3. Pediatric Poisonings (Case 54)
  4. Note Writing

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Jul 18, 2016 | Posted by in PEDIATRICS | Comments Off on Autism

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