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Autism spectrum disorder


Since being first described by Dr. Leo Kanner of John Hopkins University in 1943, the terminology used in the diagnosis and reference to autism spectrum disorder has changed multiple times, making it confusing for families and clinicians.

Autism or autism spectrum disorder?

Kanner described eleven children in his article Autistic Disturbances of Affective Contact who displayed “a need for sameness” and lacked social instinct to interact with others. He coined the disorder infantile autism, borrowing the term from Eugene Bleuler, who had used the term autism about adult patients with schizophrenia (although he did not suggest that these disorders were aetiologically related).

Subsequently, in 1944, Hans Asperger (psychologist) published an article, Die Autistischen Psychopathen im Kindesalter (Autistic Psychopathy in Childhood). There is some contention that Hans, therefore, was rewarded with an eponymous disorder (which in some countries has been since removed). In 1926, a Russian neurological assistant (Eva Sucharewa) wrote a paper on the Schizoid Personality of Childhood, thought to describe Asperger’s Disorder.

Since its original description and subsequent registration with the International Classification of Diseases and the Diseases and Statistics Manual, autism spectrum disorder has encompassed many names, including but not limited to:

Which one is correct?

This is dependent on whether the ICD (International Classification of Diseases) or DSM (Diagnostic and Statistic Manual) is used, with the majority favouring DSM due to it being regularly revised and including diagnostic criteria (as well as being the nomenclature used by other government services such as Centrelink!)

You have been referred Charlie, a 2yo boy, by his general practitioner, who suspects that he has autism.

He attends your room with his mother, who feels helpless surrounding this potential “label” being considered for her son. She has a list of questions. However, her first one is, “why is this happening to me?” 

How common is autism?

  • Approximately 1/150 Australians had a diagnosis of ASD in 2015 (0.7%)
  • 154% increase between 2009 and 2015
  • Males > Females (81% vs 29%)
  • The most commonly associated disability is intellectual impairment.

Sibling rate of 3 – 20%; the risk doesn’t vary depending on the gender of the affected child or their sibling. There is, however, difficulty in truly commenting on the sibling risk currently as studies were at the time when Aspergers were generally included (MZ twin rate 36 – 96%)

Most common associated genetic disorders:

  • Tuberous sclerosis
  • Fragile X
  • 15q chromosome deletions/duplications
  • Rett syndrome
  • Smith-Lemli-Opitz syndrome

Other chromosomal “hotspots” include chromosomes 1, 2, 3q, 5p, 7q, 11q, 12q, 13q, 16p, 17, 18q, 21p, 22q, and X.

There is contention surrounding the very significant increase in the number of persons with autism spectrum disorder and whether this represents a true increase which has occurred through either increased overall incidence or increased recognition of the disorder or whether this represents over-diagnosis. Due to the lack of a sensitive and specific diagnostic test, this is difficult to determine.

Symptoms are typically noted at 12 – 24 months but may be noted earlier where there are associated severe developmental delays; delayed diagnosis may be seen where the child is able to learn and compensate for their deficits.

What causes autism?

The aetiology and pathogenesis remain unclear, although there are multiple theories. It should be emphasized that immunisation has no association with autism spectrum disorder.­ A good fact sheet for families with this question in particular can be found at:


Autism is multifactorial, and despite advances over the last 75 years, exact pathogenesis is not determined and may indeed vary amongst children. Whilst genetic associations have been found, these are not sufficient alone and likely require an interplay of environmental stressors/triggers in order to result in the clinical condition of autism.

Suggested genetic, environmental and biological mechanisms in the development of autism

Four main accepted aetiological mechanisms (outside of genetics) include:

  1. Oxidative stress
  2. Environmental toxicants
  3. Mitochondrial dysfunction
  4. Immunology/Inflammation

It is okay to admit to our patients/families that we don’t have all the answers and don’t know the exact mechanisms surrounding aetiology/pathophysiology! 

Charlie is sitting in the corner of your room and refuses to look or speak to you. He has no interest in you or your room. Mum wants to know…is he just naughty, or is this autism? 

What are the DSM diagnostic criteria for autism?

1. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history (examples are illustrative, not exhaustive; see text):

  • Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation to reduced sharing of interests, emotions, or affect to failure to initiate or respond to social interactions.
  • Deficits in nonverbal communicative behaviours used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication to abnormalities in eye contact and body language or deficits in understanding and use of gestures to a total lack of facial expressions and nonverbal communication.
  • Deficits in developing, maintaining, and understanding relationships, ranging, for example, from difficulties adjusting behaviour to suit various social contexts to difficulties in sharing imaginative play or making friends to the absence of interest in peers.

2. Restricted, repetitive patterns of behaviour, interests, or activities, as manifested by at least two of the following, currently or by history:

  • Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypies, lining up toys or flipping objects, echolalia, idiosyncratic phrases).
  • Insistence on sameness, inflexible adherence to routines, ritualized patterns, or verbal nonverbal behaviour (e.g., extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take the same route or eating the same food daily).
  • Highly restricted, fixated interests that are abnormal in intensity or focus (e.g, strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interest).
  • Hyper- or hyporeactivity to sensory input or unusual interests in sensory aspects of the environment (e.g., apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).

3. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities or may be masked by learned strategies in later life).

4. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.

5. These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for the general developmental level.

If a diagnosis is established, it is important – from a prognostication and funding point of view – to determine the severity of the diagnosis, which is assessed based on social/communication and behaviours separately.

Severity of autism spectrum disorder

Specify if:

  • With or without intellectual impairment
  • With or without accompanying language impairment
  • Associated with a known medical or genetic condition or environmental factor
  • Associated with another neurodevelopmental, mental or behavioural disorder
  • With catatonia

What are some red flags?

  • Not responding to their name by 12 months of age
  • Not pointing at objects to show interest by 14 months
  • Not playing “pretend” games by 18 months, e.g. Feeding a baby doll
  • Avoid eye contact and want to be alone
    • Baby that doesn’t put their arms up to be picked up
    • Content to be left alone in their cot
  • Have trouble understanding other people’s feelings
  • Echolalia (repeating words/phrases)
  • Give unrelated answers to questions
  • Flap their hands, rock their body, spin in circles or toe-walking
  • Restricted interests, e.g. Specific TV ads, drains
  • Have unusual reactions to the way things sound, smell, taste, look, or feel e.g. Fluttering fingers in front of eyes to watch lights flicker

How do we make the diagnosis of autism?

Each state in Australia has a different legislature on who can make a diagnosis, be it a general paediatrician, a developmental paediatrician, a child psychiatrist or a multidisciplinary panel. Regardless, unless the child has severe level 3 autism, the diagnosis should not be made in a one-off visit. It should involve input from not only the medical assessment but also the family and the child’s school/childcare environment. It is important to consider other mimics that may result in an autism-like picture.

They may benefit from different supports for the family, e.g., a history of trauma/attachment disorder that may result in poor eye contact similar to autism diagnosis. The “Coventry Grid” can be useful for helping clinicians to recognize some of the subtle differences. 

Diagnosis should include the following:

  • A detailed history from the primary caregiver
    • Medical
    • Developmental
    • Behavioural
    • Family history (including 3-generation pedigree and enquiring specifically regarding consanguinity)
  • Physical examination
  • Developmental +/- psychometrical evaluation

Tools that may be useful include:

  • Childhood autism rating scale (CARS)
  • Gilliam Autism Rating Scale (GARS)
  • Modified Checklist for Autism in Toddlers (MCHAT)
  • Autism diagnostic observation schedule
  • Autism diagnostic interview

The most useful test is a thorough history with the caregiver and their childcare/school provider. When unsure regarding diagnosis, referral to specifically trained personnel is encouraged due to the inherent stigma associated with the lifelong diagnosis of autism.

After meeting with Charlie and his family multiple times and getting further history from his daycare, you determine that Charlie does indeed have autism. You remember that early intervention programs have been shown to improve overall outcomes but aren’t sure where to start.

What tests do we need to do?

Autism is a clinical diagnosis; medical investigations may be used to identify causal conditions or known complications/associations.

Audiological and vision evaluation

Genetics: Microarray + Fragile X

Baseline bloods:

  • FBC (associated anaemia with hyper-sensitivity to foods)
  • Lead levels
  • Iron studies

EEG, MRI and metabolic studies are not recommended routinely, although they can be considered in subset populations. There is no high therapeutic yield for these tests.


Two features of therapy are of utmost importance:

  1. Multidisciplinary (speech, occupational therapy +/- psychology)
  2. Early and timely interventions

Therapy supports the child best when it is available in multiple environments (home and school).

But what can I do as a doctor?

Nationwide, Australia is transitioning to National Disability Insurance Scheme, which requires both the family and medical professional to advocate for the young person to ensure a financial package that will support the child in all domains that are affected, including but not limited to:

  • Communication
  • Social skills
  • Hearing and Vision
  • Continence
  • Mobility aides

Other financial supports that the family may be eligible for include:

  • Chronic disease management plan
  • Better Access to Mental health care scheme (both of which can be re-submitted on an annual basis)
  • Carers allowance/payment
  • Healthcare card
  • Continence aids payment scheme/Medical aids subsidy scheme

The parents should be encouraged to notify the school in order to allow coordination of services within this environment as well as allow the development of an individualized education plan where appropriate.

What about medication?

Medication itself will not “treat” autism; however, it may be used for the associated diagnoses or difficulties seen. “Common” medications that may be seen being used by children with autism include:

  • Melatonin – for treatment of sleep dysregulation
  • Risperidone – for treatment of aggression
  • Fluoxetine – for treatment of anxiety/repetitive behaviours and rigidity
  • Movicol/Osmolax – treatment of constipation
  • Methylphenidate/dexamphetamine – treatment of concomitant ADHD

Medication is not required in all children and should be considered case-to-case.


Primary care providers should provide surveillance for:

  • Medical disorders e.g. Seizures, anaemia
  • Developmental and mental health co-morbidities, e.g. Anxiety, depression, hyperactivity, aggression 
  • Sleep problems e.g.. Delayed onset, frequent waking, restlessness
  • Feeding and weight problems (under and overweight)  +/- pica
  • Constipation


  • Mary is an advanced trainee in General Paediatrics/Community and Developmental Paediatrics. Has called Townsville home for the last decade. Outside of work, she enjoys eating and Crossfit (one of 'those people'!)


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