Autism Flashcards
What is autism?
Autism is a pervasive developmental disorder characterized by a triad of:
- Impairment in social interaction
- Impairment in communication
- Restricted, stereotyped interests and behaviours
Briefly describe the prenatal pathophysiology and aetiology of autism
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.
Briefly describe the antenatal pathophysiology and aetiology of autism
Obstetric complications such as hypoxia during childbirth, ↓ gestational age at birth, as well as very low birthweight offer increased risk of autism.
Briefly describe the postnatal pathophysiology and aetiology of autism
Toxins such as lead and mercury may increase the risk of autism.
Pesticide exposure may affect those genetically predisposed to autism.
How common is autism?
Autism affects approximately 1.1% of the population.
Is autism more common in men or women?
The ♂ to ♀ ratio is 4:1.
What are the risk factors for autism?
- Male
- Males are 4 × more likely to be affected than females
- Genetics
- 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
- Maternal medication use
- ↑ with mothers receiving sodium valproate during pregnancy
Briefly describe the triad of autism
Asocial
- Few social gestures e.g. waving, nodding and pointing at objects
- Lack of:
- Eye contact (gaze avoidance)
- Social smile
- Response to name
- Interest in others
- Emotional expression
- Sustained relationships
- Awareness of social rules
Behaviour restricted
- Restricted, repetitive and stereotyped behaviour e.g. rocking and twisting
- Upset at any change in daily routine
- May prefer the same foods, insist on the same clothes and play the same games
- Obsessively pursued interests
- Fascination with sensory aspects of environment
Communication impaired
- Distorted and delayed speech (often the first sign which is noticed)
- Echolalia (repetition of words)
Other than the triad of symptoms (asocial, behaviour restricted and communication impairment), what are the other features of autism?
Other features include:
- Intellectual disability
- Note: if you include all on the autistic spectrum the majority will not have an intellectual disability
- Temper tantrums
- Impulsivity
- Cognitive impairment may be present as associated conditions
At what age do parents notice autism in children?
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.
What other conditions are associated with autism?
- 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
- Toxoplasmosis
- Psychiatric
- Hyperkinetic disorder
- Depression
- Bipolar affective disorder
- Anxiety
- Psychosis
- OCD
- DSH
Briefly describe the ICD-10 Criteria for diagnosing autism
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.
Briefly describe the MSE for autism
Appearance and 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).
Thought: 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.
What investigations should be ordered for autism?
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).
Briefly describe Asperger’s syndrome
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.
Briefly describe Rett’s syndrome
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.
Briefly describe childhood disintegrative disorder (Heller’s syndrome)
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.
Briefly discuss the speech and hearing developmental milestones for children
Note: 3 months, 6 months, 9 months, 12 months, 12-15 months, 2 years, 3 years and 4 years
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
Briefly discuss the social developmental milestones for children
Note: 6 weeks, 6 months, 1 year, 2 years, 3 years and 4 years
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
What developmental delays do we expect in autism?
Delays in language and social interaction alone indicate likely autism. Global developmental delay indicates a likely alternative pathology.
At what age can an autism diagnosis be made?
Diagnosis should be by a specialist and can be reliably made at age 3.
Briefly describe the bio-psychosocial model of managing autism
Biological
- 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
Who is involved in the MDT of autism?
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.
Briefly discuss the treatment for the core features of autism
Social-communication intervention (e.g. play-based strategies).
Do not use pharmacological agents such as antipsychotics, antidepressants or exclusion diets.
Briefly discuss the treatment for the challenging behaviours that may arise in autism
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.
What differentials should be considered for autism?
- Asperger’s syndrome
- Rett’s syndrome
- Childhood disintegrative disorder
- Learning disability
- Deafness
- Childhood schizophrenia
