Autism

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Introduction

Everything about autism is disputed, sometimes by people who know something about it

Autism is one of a range of related conditions, sometimes referred to as autism spectrum disorders of which the most obvious other member is Asperger syndrome.

Can be associated with other neurological disorder eg fragile X, congenital rubella, tuberosclerosis, but these are only 10% or so of all cases.


The principle features of this condition are:

  • Impaired social communication
  • Impaired reciprocal social interactions
  • Restricted range of interests and obsessive preoccupation with these interests

The American Academy of Pediatrics has recently published guidance.[1]

Contents

Clinical vignette

This vignette is not based on any particular patient; it is a composite of many different features, designed to make "spot diagnosis" easier....


Roger is a thirteen year old schoolboy. He has an obsessive interest in dinosaurs, with a tendency to discuss this to the exclusion of all other subjects. He is quite unpopular amongst his peers, with very few friends, but is more at ease in the company of adults. As a young child, he spoke unintelligibly up to the age of seven, but has since developed a rather 'flat', monotonous communication style. At times, his rigidity brings him into angry confrontation with his parents. He has great difficulty adapting to new changes in the family. A particular problem is with any alteration in his routines. When mealtimes were altered recently, he became very anxious for several weeks until he got used to this change.

Epidemiology

The incidence, and changes in incidence with time and variations in incidence in different areas and population groups are difficult to determine. Prevalence in the UK is currently estimated at 1 in 225 people: new diagnoses have levelled out after peaking in 1992, the surge probably reflects increased awareness and changes in diagnostic criteria rather than any real change in prevalence.

Aetiology

Epilepsy is associated with autism, which would suggest a neurological cause. Siblings have a 2-6% risk, suggesting a polygenic cause. Brain scans have not demonstrated any consistent abnormality.

Systemizing

Men, scientists, mathematicians in particular tend to systemize eg maps, calendars, timetables. Asperger himself suggested that the syndrome he described in some ways represented the extreme end of natural male behaviour. Systemizing is a way of trying to understand the world. One way of doing this is repetitive experimentation, until a pattern is discerned. In lower level autism, children never move beyond the experimentation, so that the repeated action seems to offer a level of security, that the world is predictable, and does not change all the time. The disadvantage of trying to systemize the world is that you struggle with things that are unpredictable, especially language, emotion and behaviour. These are entities that are better understood by empathizing, ie recognizing that another being is involved, with their own internal world. Parents of children with autism tend to be high level systemizers. [2]

Clinical

Early signs

Usually presents around 18 months. In a minority there will be regression, accompanied by social withdrawal - but in retrospect development before presentation was almost always abnormal.

  • Lack of social smile, facial expression (affect atunement, ie where mother/baby reflect each other's expressions)
  • Poor attention
  • Ignoring people, preference for own company
  • Lack of eye contact, emotional expression
  • Less pointing/showing (joint attention, ie getting someone else to share what you're interested in)
  • Fewer gestures/actions eg clapping

Absolute indicators for referral:

  • No babble, pointing or other gesture by 12 months
  • No single words by 18 months
  • No 2 word phrases by 24 months (parroting does not count)
  • Loss of language or social skills at any stage

Alerting Signals:

Communication:

  • Poor comprehension, initiation, responsiveness
  • Unusual use of language - idiosyncratic or stereotyped
  • Poor response to name
  • Persistent echolalia
  • Reference to self in third person eg "you", by own name (after 3 yrs)
  • Inability to join in with play of other children (sometimes disruptive)

Social:

  • Lack of imitation eg actions
  • Lack of interest in other children eg sharing of interests, activities
  • Minimal response to emotions in others (eg happiness, distress)
  • Limited imaginative play, esp with others
  • Odd relationship with adults, either too friendly or ignores

Behaviour:

  • Oversensitivity to touch/sound
  • Fascination with texture, odour
  • Mannerisms eg hand/finger flapping
  • Inability to cope with change
  • Restricted interests, esp odd, intense
  • Obsessions/Compulsions viz routines

Older children

In most autistic children, most advanced skills eg manipulation of mechanical objects, music, drawing are delayed, or else one is relatively preserved. But in mild cases where the diagnosis is made late, one skill is sometimes seen to be particularly advanced, and this curious feature has been highlighted in popular culture eg the idiot savant, Rain Man.

  • Talk is one sided, odd, possibly more free about certain favourite topics (ICD 10 does not require language/developmental delay for Asperger's)
  • If language skills are good, conversation may be long winded and literal
  • Lack of awareness of "norms"
  • Easily overwhelmed by social stimulation
  • In play, acts out the same theme repetitively eg Batman
  • Poor empathy and peer interaction
  • Collects facts, enjoys repetitive activities/questions
  • Clumsy, lack of arm swing when walking, stooped! Difficult to explain...

Investigations

For screening, Childhood Autism Rating Scale (CARS) is a commercial product with 15 items. CHAT (Checklist for autism in toddlers) is a 5 item examination plus parental rating test, but poor sensitivity.[3] It has been modified into 23 item M-CHAT which appears to be much more sensitive, without any expense in specificity.[4]

The Autism Diagnostic Interview (Revised) (ADI-R) is a semi-structured interview administered to parents/relatives which reviews developmental history and current behaviour according to ICD/DSM criteria. It takes about 2-3 hours and must be administered by a trained interviewer to be reliable.

The Autism Diagnostic Observation Schedule (ADOS) is a semi-structured observational assessment which assesses an individual's behaviour and social interaction against criteria for autism. It takes 45-60min and must be administered by a trained interviewer to be reliable. There are 4 different versions tailored for different levels of language skills.

Although the ADI-R and ADOS are considered the "gold standard" assessments for diagnosing autism, the diagnosis remains a clinical one which may be guided by these assessments.

QuotationMarkLeft.png The Checklist for Autism in Toddlers (CHAT) is a screening instrument which identifies children aged 18 months who are at risk for social-communication disorders. Looks for lack of pretend play and pointing, lack of social interest/play, lack of joint attention.  QuotationMarkRight.pngNAS website

Differential diagnosis

Organic/Developmental disorders


Functional psychiatric disorders
Social causes

Severe neglect (e.g. Romanian orphans)

Management

Needs to be individualized.

  • Vocabulary, grammar, reading
  • Social Pragmatics covers the use of language in different social contexts, including discourse rules eg turn taking
  • Visual language aids
  • Memory devices eg felt notice boards
  • SSRIs for hyperactivity, agitation or obsessions
  • Atypical antipsychotics. Risperidone improved behaviour in a majority of patients, but perhaps aggressive behaviour is a symptom of communication disorder and should be managed as such?
  • "More than words" Hanen parents programme
  • Nursery in-service training
  • Intervention groups eg early intervention programme (1 to 1 play sessions, following the child's lead to capture interest, copy the child's actions and words, gradually introducing new ideas)
  • Parents' groups.

What doesn't work:

  • Gluten-Casein free diet. An early RCT of 20 children showed benefit but subsequent studies have not confirmed. Difficult anyway, considering food behaviour.
  • Vitamin B6 and Magnesium popular. Early studies were flawed, later failed to show benefit.
  • Chelation therapy - goes along with heavy metal theory. Invasive, and at least 1 child has died from it.
  • Secretin therapy - (IV infusion). 12 of 13 studies failed to show benefit.

Other associated problems:

  • Sleep. Common, and aggravates other behaviours. Electronic alerting systems eg WanderGuard are available which avoid having to lock bedroom doors. Durand and Schreck have written on environmental/behavioural strategies.
  • Feeding. Common, variable patterns. Establish an effective meal routine, consistently present new foods, and address food refusal early.
  • GI problems. Up to 70% have GI symptoms. Severe food selectivity may be a cause, but otherwise investigate and treat to prevent it affecting behaviour etc.

External links

References

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