Autism Spectrum Disorder (ASD)

Question 1

What is autism?

Answer 1

Autism is a pervasive developmental disorder characterized by a triad of impairment in social interaction, impairment in communication, and restricted, stereotyped interests and behaviours.

Question 2

What are the prenatal causes of autism?

Answer 2

Genetics: there is a complex polygenic relationship, with a number of chromosomes implicated, such as chromosome 7. There is a significantly increased risk of autism associated with genetic syndromes such as fragile X syndrome and tuberous sclerosis.

Parental age: a study found that women who are 40 years old have a 50% greater chance of having a child with autism as compared with women aged 20– 29 years.

Drugs: babies who have been exposed to certain medications in the womb have a greater risk of developing autism. These include sodium valproate in particular.

Infection: prenatal viral infections (e.g. rubella ) increase the risk of autism.

Question 3

What are the antenatal causes of autism?

Answer 3

Obstetric complications such as hypoxia during childbirth, ↓ gestational age at birth, as well as very low birthweight offer increased risk of autism.

Question 4

What are the perinatal causes of autism?

Answer 4

Toxins such as lead and mercury may increase the risk of autism.

Pesticide exposure may affect those genetically predisposed to autism.

Question 5

How common is autism in the UK?

Answer 5

Autism affects approximately 1.1% of the population.

Question 6

Which gender is most likely to have autism?

Answer 6

The male to female ratio is 4:1.

Question 7

What are the risk factors for autism?

Answer 7

• Male
  
  • Males are 4 × more likely to be affected than females
• Genetics and family history
  
  • There is an 88% concordance rate in monozygotic twins, indicating a strong genetic component
• Advancing parental age
  
  • Recent studies have suggested that advancing parental age is a significant risk factor for ASD
• Parental psychiatric disorders
  
  • Evidence suggests a link between parental psychiatric disorders such as schizophrenia and the child having autism
• Prematurity
  
  • Born before 35 weeks’ gestation
• Materanl medication
  
  • ↑ with mothers receiving sodium valproate during pregnancy

Question 8

What are the 3 clinical features of autism?

Answer 8

The triad of clinical features associated with autism as mentioned in ICD-10 fit the mnemonic ‘ABC’:

• Asocial
• Behaviour restricted
• Communication impaired

Question 9

What is the average age of onset of autism?

Answer 9

50% of parents have cause for concern by 12– 18 months of age. The onset of autism is before the age of 3 years. There is also a diagnosis of atypical autism after the age of 3.

Question 10

Briefly describe the asocial features of autism

Answer 10

• Lack of eye contact
• Delay in smiling
• Avoids physical contact
• Unable to read non-verbal cues
• Difficulty establishing friendships
• Not displaying a desire to share attention (i.e. not playing with others)

Question 11

Briefly describe the behavioural features of autism

Answer 11

• Greater interest in objects, numbers or patterns than people
• Stereotypical repetitive movements. There may be self-stimulating movements that are used to comfort themselves, such as hand-flapping or rocking.
• Intensive and deep interests that are persistent and rigid
• Repetitive behaviour and fixed routines
• Anxiety and distress with experiences outside their normal routine
• Extremely restricted food preferences

Question 12

Briefly describe the communication features of autism

Answer 12

• Delay, absence or regression in language development
• Lack of appropriate non-verbal communication such as smiling, eye contact, responding to others and sharing interest
• Difficulty with imaginative or imitative behaviour
• Repetitive use of words or phrases

Question 13

What other conditions are associated with autism?

Answer 13

• Epileptic seizures (20% develop this)
• Visual impairment
• Hearing impairment
• Infections
• Pica (eating inedible objects)
• Constipation
• Sleep disorders
• Underlying medical conditions
  
  • PKU, fragile X, tuberous sclerosis, congenital rubella, CMV or toxoplasmosis
• Psychiatric
  
  • Hyperkinetic disorder, depression, bipolar affective disorder, anxiety, psychosis, OCD and DSH

Question 14

Briefly describe the ICD-10 Criteria for diagnosing autism

Answer 14

A. Presence of abnormal or impaired development before the age of three.

B. Qualitative abnormalities in social interaction.

C. Qualitative abnormalities in communication.

D. Restrictive, repetitive and stereotyped patterns of behaviour, interests and activities.

E. The clinical picture is not attributable to other varieties of pervasive developmental disorder.

Question 15

Briefly describe the MSE for autism

Answer 15

Appearance & Behaviour: ritualized, stereotyped behaviour, e.g. clapping, rocking. Poor eye contact, detached. Lack of facial expression and gestures. May attach to unusual items.

Speech: delayed speech. Difficulty initiating and maintaining conversation. Repetitive language. May have unusual rate, rhythm and volume.

Mood: normal or have erratic mood changes (can appear to have a labile mood). Obsessions and compulsions. Intense preoccupation with special interests.

Perception: may be very sensitive to noise, touch or smell.

Cognition: impaired attention but may also be able to concentrate on special interests.

Insight: may be poor but they may be distressed if aware they are different/ don’t fit in.

Question 16

What are the investigations for autism?

Answer 16

Full developmental assessment including family history, pregnancy, birth, medical history, developmental milestones, daily living skills and assessment of communication, social interaction and stereotyped behaviours.

Hearing tests if required.

Screening tools including CHAT ( CHecklist for Autism in Toddlers).

Question 17

Briefly describe Asperger’s Syndrome

Answer 17

Similar to autism with abnormalities in social interaction and restricted, stereotyped, repetitive interests and behaviours. However, unlike autism, there is no impairment in language, cognition or intelligence (IQ normal). It is more prevalent in boys.

Question 18

Briefly describe Rett’s Syndrome

Answer 18

Severe, progressive disorder starting in early life. Results in language impairment, repetitive stereotyped hand movements, loss of fine motor skills, irregular breathing and seizures. Almost exclusively seen in girls. The MECP2 gene’s role in Rett’s syndrome has been identified.

Question 19

Briefly describe childhood disintegrative disorder (Heller’s syndrome)

Answer 19

Characterised by two years of normal development followed by loss of previously learned skills (language, social and motor). Also associated with repetitive, stereotyped interests and behaviours as well as cognitive deterioration.

Question 20

What are the speech and hearing developmental milestones?

Note: 3 months, 6 months, 9 months, 12 months, 12-15 months, 2 years, 3 years and 4 years

Answer 20

3 months→ turns towards sound, quietens to parent’s voice.

6 months→ double syllables e.g. ‘adah’.

9 months→ says ‘mama’ and ‘dada’.

12 months→ knows and responds to own name.

12– 15 months→ knows about 2– 6 words, understands simple commands.

2 years→ combines two words.

3 years→ talks in short sentences (e.g. 3– 5 words), asks ‘what?’ and ‘who?’ questions.

4 years→ asks ‘when?’, ‘how?’ and ‘why?’ questions.

Question 21

What are the social developmental milestones?

Note: 6 weeks, 6 months, 1 year, 2 years, 3 years and 4 years

Answer 21

6 weeks→ smiles (refer at 10 weeks if not smiling).

6 months→ enjoys interaction.

1 year→ waves bye-bye.

2 years→ interested in other children.

3 years→ make believe play.

4 years→ plays with other children.

Question 22

Briefly describe the important general approach to managing autism

Answer 22

Diagnosis should be by a specialist and can be reliably made at age 3.

Local autism teams (community-based multidisciplinary teams including paediatricians, psychiatrists, educational psychologists, speech and language therapists and occupational therapists) should ensure that all those diagnosed with autism have a key worker to manage and coordinate treatment.

CBT can be used if the child has the verbal and cognitive ability to engage and is motivated.

Interventions for life skills include support developing their daily living skills, their coping strategies and enabling access to education and community facilities such as those related to leisure and sports.

Ensure all physical health, mental health and behavioural issues are addressed.

Families and carers should also be offered personal, social and emotional support. Self-help groups such as the National Autistic Society (NAS) are available.

Special schooling may be considered.

Melatonin may be considered for sleep disorders that persist despite behavioural interventions.

Question 23

Briefly describe the management of the core symptoms of autism

Answer 23

Social-communication intervention (e.g. play-based strategies).

Do not use pharmacological agents such as antipsychotics, antidepressants or exclusion diets.

Question 24

Briefly describe the management for challenging behaviours in autism

Answer 24

Treat co-existing physical disorders (e.g. epilepsy and constipation) and mental health (e.g. anxiety, depression) and behavioural problems (e.g. hyperkinetic disorder).

Modification of environmental factors which initiate or maintain challenging behaviour, are the first line in management (e.g. lighting, noise, social circumstances and inadvertent reinforcement of challenging behaviour).

Antipsychotics (e.g. risperidone) should be considered for behaviour that challenges, when psychosocial interventions are insufficient or if the features are severe. This requires careful consideration as there are significant side effects, and metabolic monitoring is required.

Question 25

Briefly describe the bio-psycho-social for managing autism

Answer 25

• Biology
  
  • Treat co-existing disorders (e.g. methylphenidate for hyperkinetic disorder)
  • Antipsychotics for behaviour that challenges
  • Melatonin
• Psychological
  
  • Psychoeducation for families or carers
  • Full assessment of the functions of behaviour, to understand the child fully
  • CBT
• Social
  
  • Modification of environmental factors
  • Social-communication intervention
  • Self-help groups such as the National Autistic Society
  • Special schooling

Question 26

What differentials should be considered for autism?

Answer 26

• Asperger’s syndrome
• Rett’s syndrome
• Childhood disintegrative disorder
• Learning disability
• Deafness
• Childhood schizophrenia