Developmental Delay and Learning Disability Flashcards
What is the most common genetic cause of developmental delay?
Down’s syndrome
1/600 pregnancies
How is Down’s syndrome screened for?
Combined test (10 weeks - 14 weeks + 1 day):
Serum screening - beta-HCG and PAPP-A
US screening - nuchal translucency
If later = quadruple test (14 weeks + 2 days - 20 weeks + 0):
- beta-HCG
- AFP
- Inhibin-A
- Unconjugated estriol (uE3)
List the possible genetic defects in Down’s syndrome
1) Trisomy 21 = 94%
2) Mosaicism = 2.4%
3) Translocations = 3.3%
NB 75% of these translocations are de novo errors
What is a trisomy 21?
Additional copy of an entire chr 21
In most cases it is maternally derived, through an error in cell division called non-dysjunction (can be during meiosis or a mitotic error)
What is partial trisomy 21?
When only a segment of chr 21 has three copies
What is mosaicism?
When the whole chromosome is triplicate but only a proportion of the cells are trisomic with the other cells being normal
What is translocation in Down’s syndrome?
Some of the genetic material from chr 21, usually from the long arm, is moved to chr 14 or 22, or from the long to the short arm of chr 21
What are some risk factors for Down’s syndrome? (2)
1) Inc maternal age
2) FH
What is typically the first feature noticed in Down’s syndrome?
Hypotonia
What are some general neonatal features of Down’s syndrome?
Hyper-flexibility
Hypotonia
Transient myelodysplasia of the newborn
What are the neonatal features of Down’s syndrome in the head?
Brachycephaly Oblique palpebral fissures Epicanthic folds Ring of iris speckles = Brushfield's spots Ears set low, folded or stenotic meatus Flat nasal bridge
What are the neonatal features of Down’s syndrome in the mouth?
Macroglossia
High arched palate
What are the neonatal features of Down’s syndrome in the hand?
Single palmar crease
Short little finger
In-curved little finger
Short broad hands
What are the neonatal features of Down’s syndrome in the feet?
Sandal gap between hallux and second toes
How may the heart and GIT be affected in Down’s syndrome?
Congenital heart defects
Duodenal atresia
What is transient myelodysplasia of the newborn?
= transient neonatal preleukaemic syndrome
Majority undergo remission
10% progress to myeloid leukaemia of Down’s syndrome
What screening should newborn’s with Down’s syndrome undergo?
Cardiac Feeding Vision Hearing Thyroid Haematological
What % of newborns with Down’s syndrome have a congenital heart defect? How should this be investigated?
50%
Often undetectable on prenatal US
Need echocardiogram
What should marked hypotonia or other feeding difficulties prompt in Down’s syndrome?
Radiographic swallowing
How is congenital cataracts checked for?
Red reflex
Why should a FBC be included in for newborns with Down’s syndrome?
Increased risk of transient myeloproliferative disorder, leukaemoid reaction and polycythaemia
How frequently do children with Down’s syndrome need review?
Annual checks of: Feeding assessment Bladder and bowel function Behavioural disturbance Vision and hearing
What are the most common cardiac abnormalities in Down’s syndrome? (6)
1) Atrioventricular canal defects
2) VSD
3) Isolated secundum atrial septal defects
4) Isolated persistent patent ductus arteriosus
5) Fallot’s tetralogy
6) Adults may develop mitral valve prolapse or aortic regurgitation
What ENT disorders are common in Down’s syndrome? (5)
1) 90% have hearing loss (conductive, sensorineural or mixed)
Inc risk of:
2) OM
3) Sinusitis
4) Pharyngitis
5) Obstructive sleep apnoea
What ophthalmological disorders are common in Down’s syndrome? (6)
1) Cataracts
2) Refractive errors
3) Strabismus
4) Nystagmus
5) Congenital glaucoma
6) Keratococonus
What GI disorders are common in Down’s syndrome? (9)
1) Oesophageal atresia or tracheo-oesophageal fistula
2) Duodenal atresia
3) Pyloric stenosis
4) Meckel’s diverticulum
5) Hirschsprung’s disease
6) Imperforate anus
7) GOR
8) Dental problems eg delayed and unusual patterns of eruptions, missing teeth
9) Coeliac disease
What orthopaedic disorders are common in Down’s syndrome?
1) Atlanto-axial instability
2) Hyperflexibility
3) Scoliosis
4) Hip dislocation
5) Patellar subluxation or dislocation
6) Foot deformities
What endocrine disorder is common in Down’s syndrome? (1)
Hypothyrodism
What neurological and psychiatric disorders are common in Down’s syndrome? (4)
1) Learning difficulties - range from severe to those with ‘low normal’ IQ
2) Behavioural problems
3) Seizures in 5-10%
4) In older - Alzheimer’s type picture develops in >60% of those over 60yrs
What haematological disorders are common in Down’s syndrome?
1) 12x greater risk of infection eg pneumonia due to impaired cellular immunity
2) Increased risk of acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL) and acute megakaryoblastic leukaemia (AMegL)
3) Polycythaemia and transient myeloproliferative disorder (self-limiting type of leukaemia which regresses spontaneously by age 2 months)
What is a strabismus?
A squint
Misalignment of the eyes (eyes point in different directions)
Thus the retinal image is not in corresponding areas of both eyes
- Amblyopia in childhood
- Diplopia in adults
What is amblyopia?
Eye fails to achieve normal visual acuity
= Lazy eye
What is esotropia?
Inward-turning squint
What is exotropia?
Outward-turning squint
What are hypo- and hypertrophic?
Downward and upward turning squint
How common are squints?
1/15 children
Increased incidence in learning disability + brain damage
What is the cause of strabismus?
Can occur in otherwise normal children - most idiopathic
Rarer causes:
Cataract
Retinal disease / retinoblastoma
Glaucoma
What is infantile (congenital or essential) strabismus?
Common condition characterised by a squint in an otherwise normal infant with no refractive error
Early childhood strabismus common and usually settles by 4 months = this type is always intermittent
What are the different ways of classifying strabismus?
1) Congenital (<6 months) or acquired
2) Right, left or alternating
3) Permanent or intermittent
3) Manifest (when open) or latent (when covered/shut)
4) Concomitant (non-paralytic) or incomitant (paralytic)
5) Primary, secondary or consecutive
6) Situational eg reading
What are concomitant (non-paralytic) or incomitant (paralytic) strabismus?
Concomitant = size of the deviation does not vary with direction of gaze (non-paralytic)
- More common
Incomitant = direction of gaze affects size / presence of quint
Most estropeas are concomitant and begin age 2-4yrs
Incomitant occurs in both childhood and adulthood as a result of neurological, mechanical or myogenic problems affecting the muscles controlling eye movements
When are manifest and latent strabismus seen?
Manifest = obvious at all times
Latent = only found on investigation, usually when tired
What are some risk factors for strabismus? (11)
1) FH
2) Prematurity
3) Neonatal jaundice
4) Encephalitis
5) Meningitis
6) CP
7) Craniofacial abnormalities
8) Learning difficulties +/- syndromes eg Down’s syndrome or Turner syndrome
9) Fetal alcohol syndrome
10) Hydrocephalus
11) Space occupying lesions
How may strabismus present in children? (4)
1) Intermittently closing one eye - intermittent exotropia (esp in sunlight)
2) Reduced motor skills in amblyopic children
3) May be detected in preschool screening
4) Compensatory head tilt or chin lift to minimise diplopia
What can be done on examination of a squint?
Corneal light reflex
Red reflex - appears pale in squinty eye
Occular movement tests
Visual acuity
Cover test - good eye is covered so the squinty eye has to move to take up fixation
What is the corneal light reflex test?
= Hirschberg’s test
Gives estimate of degree of strabismus
Hold pen torch an arms length from pt eye + ask pt to look at the light
Observe position of reflection with respect to the cornea
- If light on outer margin = esotropia
- Inner margin = exotropia
What is the cover/uncover test?
Pt asked to focus on object in front of them
One eye occulded for several second and uncovered eye is observed for movement
Movement of eye outwards = esotropia (eye was turned inwards initially)
Movement of eye inwards = exotropia (eye was turned outwards initially)
What is the alternate cover test?
Similar to cover test but occluder rapidly switched from one eye to another
Shows latent exe/esotropia
Medial rectus
Direction of pull =
Result of paralysis =
Cranial nerve =
Medial rectus
Direction of pull = medial
Result of paralysis = lateral
Cranial nerve = III
Superior rectus
Direction of pull =
Result of paralysis =
Cranial nerve =
Superior rectus
Direction of pull = upwards
Result of paralysis = downwards
Cranial nerve = III
Superior oblique
Direction of pull =
Result of paralysis =
Cranial nerve =
Superior oblique = SO4
Direction of pull = down and out
Result of paralysis = up and in
Cranial nerve = IV
Lateral rectus
Direction of pull =
Result of paralysis =
Cranial nerve =
Lateral rectus = LR6
Direction of pull = lateral
Result of paralysis = medial
Cranial nerve = VI
What is a pseudosquint?
Prominent epicanthal folds create the illusion of a squint
What is the management of a squint?
Refractive error corrected using glasses
Eye patch on good eye encourages use of squinting eye
Surgery to correct rectus muscle alignment
What squint is seen in a CN III palsy?
“Down and out”
Inferior oblique
Direction of pull =
Result of paralysis =
Cranial nerve =
Inferior oblique
Direction of pull = up and out
Result of paralysis = down and in
Cranial nerve = III
Inferior rectus
Direction of pull =
Result of paralysis =
Cranial nerve =
Inferior rectus
Direction of pull = downwards
Result of paralysis = upwards
Cranial nerve = III
What is autistic spectrum disorder (ASD)?
1) Presence of abnormal or impaired development that is manifest before the age of 3yrs, and
2) Characteristic type of abnormal functioning in all 3 areas of psychopathology, reciprocal social interaction, communication and restricted, stereotyped, repetitive behaviour
Other features:
- Phobias
- Sleeping and eating disturbances
- Temper tantrums
- Self directed aggression
What are some causes of ASD?
Genetic factors
Prenatal factors:
- Advanced parental age
- Exposure to teratogens
- Maternal DM
- TORCH
Perinatal factors:
- Low birth weight
- Prematurity
- Birth asphyxia
Postnatal factors:
- AI disease
- Viral infection
- Hypoxia
- Mercury toxicity
How common is ADD?
1% children
and 1% adults
How may ADD present?
Communication difficulties and impaired imagination:
- Delay in speech development
- Echolalia = repeated words
- Neologisms
- Speech abnormalities in pitch, rate and rhythm
- Reciprocal social interaction difficulties
- Lack of empathy / understanding of emotions and behaviours
- Restricted, obsessive and repetitive behaviours
- Social anxiety
- Sensory mis-wiring = confusion of taste and smell
- Learning difficulties
What medical problems are associated with ADD?
1) Epilepsy (approx 30%)
2) Visual and hearing impairment
3) Mental health - depression, anxiety, OCD
4) LD
5) Underlying medical conditions eg untreated phenylketonuria
6) Sleep disorders
Ddx for ADD
1) Deafness
2) General LD
3) Childhood disintegrative disorder = Heller’s disease
4) Rett syndrome
What is Rett syndrome?
AN x-linked neurodevelopmental condition characterised by loss of spoken language and hand use with the development of distinctive hand stereotypes
How is ADD diagnosed?
Reliably diagnosed between 2-3yrs
Specialist diagnosis - paediatric neurologists, developmental and behavioural paediatricians, child psychiatrists and psychologist = ASD team
- Involvement SALT and OT, special educators and social workers
Exclude other conditions
Who should be referred to ASD team?
Children who show regression in language, social or motor skills
What is the management of ADD?
Specialist education support
Behavioural management
Parent education
Speech therapy
What are the commonest causes of blindness?
1) Optic atrophy
2) Congenital cataracts
3) Choroidoretinal degeneration
50% genetically determined
33% related to perinatal problems eg retinopathy of prematurity
What % of children with blindness have additional disabilities?
50%
How may visual impairment present?
Eye may look abnormal or have unusual movements
If deficit is congenital, early smiling is inconsistent and there is no turning towards sound
Reaching for objects and pincer grip delayed
Early language may be normal but complex language may be delayed
Blindisms may occur
Suspect in neonates if:
- Cataracts
- Nystagmus
- Purposeless eye movements present
What is a blindism?
Eye poking, eye rubbing and rocking
Probably occur as they induce pleasurable visual gratification of retinal origin
How is blindness management?
Early intervention to improve developmental progress, reduce blindisms and increase parental confidence
Support at school / expert teaching assistance
What examination can be done for blindness?
Visual evoked response (VER)
Electrophysiological method of evaluating the response to light and special visual stimuli
What are causes of deafness in childhood?
4% children have hearing deficits
Conductive:
- Persistent effusions in middle ear - complication of OM known as chronic secretory otitis media / glue ear
Sensorineural:
- Damage to cochlear or auditory nerve (rarer but a cause of more significant disability)
- Genetic
Intrauterine: - Congenital infection eg rubella / CMV - Perinatal: - Birth asphyxia
Postnatal:
- Meningitis
- Encephalitis
- Head injury
When is deafness often picked up?
Neonatal screening
How may deafness present?
Lack of response to speech
Delayed speech
Behavioural problems
Associated problems - LD, neurological disorders, visual deficits
What is the management of deafness?
Grommets - in children with persistent conductive hearing loss
Hearing aids for sensorineural deafness
Early speech therapy
Cochlear implant surgery for moderate to severe sensorineural deafness
List a developmental warning sign at 10 weeks
No smiling
List some developmental warning signs at 6m (4)
Persistent primitive reflexes
Persistent squint
Hand preference
Little interest in people, toys, noises
List some developmental warning signs at 10-10m (3)
No sitting
No double-syllable babble
No pincer grasp
List some developmental warning signs at 18m (3)
Not walking independently
Fewer than 6 words
Persistent mouthing and drooling
List a developmental warning sign at 2.5 yrs (1)
No 2 or 3 word sentences
List a developmental warning sign at 18m (1)
Unintelligible speech
List some idiopathic causes of developmental delay
Autism
Various dysmorphic syndrome
List some chromosomal abnormalities that cause of developmental delay
Down’s syndrome
Fragile X
List some perinatal injuries that can cause of developmental delay
Asphyxia
Birth trauma
List some prenatal traumas that can cause of developmental delay
Fetal alcohol syndrome Intrauterine infection (TORCH)
List some endocrine and metabolic defects that can cause of developmental delay
Congenital hypothyroidism
Phenylkentonuria
List a neurodegenerative disorder that can cause developmental delay
Leucomalacia
List some neurocutaneus that can cause developmental delay
Sturge-Weber
Neurofibromatosis
Tuberous sclerosis
List some postnatal injuries that can cause developmental delay
Meningitis
NAI
Neglect
List some CNS malformations that can cause developmental delay
NTDs
Hydrocephalus
Is a delay in a single area more or less concerning than global delay?
Less concerning
What is fragile X syndrome?
Most common cause of sex-linked, general learning disability
How does fragile X syndrome present?
Learning difficulties (IQ <70) Delayed milestones
Physical features:
- High forehead
- Large testicles
- Facial asymmetry
- Large jaw
- Long ears
+/- connective tissue disorder:
- Prominent ears
- Hyperextensible finger joints
- Mitral valve prolapse
May have fits and behavioural problems
Who are more affected by fragile X?
Boys more severely
Girls carrying chromosome can have mild learning disability
