Intellectual disability Flashcards
What is the definition of intellectual disability?
Significantly low intellectual functioning - IQ<70
- Impairments in adaptive behaviour when taking into account age
- Onset of intellectual impairment before 18
What is mild intellectual disability?
IQ: 50-69 1.5-3% prevalence 85% of all IDs Learning disability Need help if problems arise Can sustain relationships and hold a routine job
What is moderate intellectual disability?
IQ: 35-49
0.5% prevalence
Capable os substantial autonomy in daily living with some supervision
Can communicate adequately and do simple household tasks
May need a supervised environment and work in sheltered workshop
What is severe intellectual disability?
IQ: 20-24 0.5% prevalence Need help with daily living Can wash and usually continent Often physically disabled Only limited communication, often not by speech Need continuous care
What is profound intellectual disability?
IQ: <20 0.05% prevalence Need extensive or total help with daily living Minimal communication Need continuous care
What is the aetiology of intellectual disability?
More common in males and higher prevalence in lower social classes
Associated with - overcrowding, poverty, irregular unskilled employment
30% have NO identifiable cause
Can be a POLYGENETIC inheritance of low intelligence Environmental - social and educational deprivation Genetic/chromosomal factors
Pre-natal, perinatal and post-natal factors
What is down’s syndrome?
Trisomy 21
Most common cause
Characteristic physical abnormalities
Increased risk of deafness, cataracts, hypothyroidism and early onset AD
What is fragile X syndrome?
abnormality on long arm of chromosome X
2nd most common cause
More common in males
Physical abnormalities - elongated face, protruding ears
What causes Cri du chat syndrome?
Deletion of short arm of chromosome 5
What is tuberous sclerosis?
Mutation in tumour-suppressor gene on chromosome 9 or 16
Results in autism or epilepsy with ID
Skin changes and tumours of the brain/other organs
What is neurofibromatosis?
mutation of gene on chromosome 17
Usually with mild ID
Abnormalities of skin, soft tissues, nervous system and bone
What is phenylketonuria?
1/10,000 Autosomal recessive High serum phenylalanine ID with short stature, hyperactivity, irritability, epilepsy, lack of pigment and eczema
What are prenatal causes of intellectual disability?
Congenital infection- rubella, toxoplasmosis, CMV, syphilis Foetal alcohol syndrome Drugs- illicit or teratogenic Placental insufficiency Congenital hypothyroidism Pre-eclampsia
What are perinatal causes of intellectual disability?
Hyperbilirubinaemia
Intraventricular haemorrhage
Birth trauma and hypoxia
What are postnatal causes of intellectual disabilities?
Childhood brain tumour Malnutrition Brain infection- meningitis, encephalitis Head injury Chronic lead poisoning
What are the environmental causes of intellectual disability?
Poor, socioeconomically deprived
Neglect
Poor linguistic and social stimulation
Abuse
What are possible presenting features in autism and ID?
Repetitive movements Little interaction with mother Do not run to greet parents Little eye contact Speech - no speech, repetition, pronoun reversal Poor non-verbal communication No imaginative play Carry the same object around Can be clumsy at copying movements Temper tantrums
What are the classical features of Asperger’s syndrome?
Good speech but literal and long winded Long monologues regardless of response Monotonous Good memories but not interested in wider applications Lack of common sense Physically clumsy
What is the behavioural approach for the management of autistic spectrum disorder?
Graded changes: Deal with obsessions Aim to reduce frequency gradually Positive reinforcement and reward Setting limits: Tackle challenging behaviour Interrupt destructive behaviour but avoid the word no Use short and concrete explanation Allow tantrum to run itself out Education: Provide framework for order, routine and structure Physical prompting and visual demonstration to help understanding Teaching material is precise and specific Help develop any skills Others: Counsel the parents Medication is not very useful Aggressive outbursts can usually be understood by environmental factors
How can schizophrenia present in those with ID?
Hard to diagnose with IQ <45
More common with more severe ID
Poverty of thought
Distinguish negative symptoms from deterioration in previous level of functioning
Can present with fear, withdrawal, challenging behaviour and sleep disturbance
Delusions are less elaborate
Hallucinations are SIMPLER and REPETITIVE
Persecutory delusions and thought disorder are LESS common Earlier age of onset
How does ID effect epilepsy?
More common in severe ID
44% of patients with at least moderate ID have epilepsy by the age of 22
4 times more common in males
Need to have caution with psychiatric medications- may lower seizure threshold
Compliance to drugs may be an issue
Inadequate control of fits can lead to poly pharmacy
Recording of fits may be difficult
Need to assess for side effects of anticonvulsant medication
Need to recognise non-epileptic attacks
Frequent attacks may lead to overprotection by carers/parents
Need to educate parents/carers about emergency treatment of prolonged fits
Social implications of epilepsy need to be considered
How can adaptive functioning in ID be achieved?
Educational and vocational programmes
Family education and support
Behaviour therapy for behavioural difficulties
Medication may be needed for aggressive/destructive behaviour- antipsychotics, benzodiazepines, lithium, carbamazepine
Appropriate residential placement
Treatment of co-morbid psychiatric and medical conditions
