Learning disability.

Question 1

Define learning disability

Answer 1

Learning disability (mental retardation) = state of arrested or incomplete development of the mind. Characterised by impaired skills manifested in the developmental period (e.g. cognitive, language, motor and social abilities)

Question 2

Triad of LD

Answer 2

1. Low intellectual performance (IQ <70)
2. Onset during birth or early childhood
3. Wide range of functional impairment (e.g. social handicap…)

Question 3

Define impairement

Answer 3

any loss or abnormality of psychological, physiological or anatomical structure or function

Question 4

Define disability

Answer 4

any restriction or lack of ability to perform an activity in the manner or w/in the range considered normal for a human being

Question 5

Define handicap

Answer 5

a disadvantage for a given individual, resulting from impairment or disability that limits or prevents the fulfilment of a role that is normal for that individual

Question 6

ICD-10 criteria mental retardation

Answer 6

F70-79

4 categories depending on the severity

Question 7

Mild mental retardation

Answer 7

• IQ 50-69 (Mental age: 9-12)
• Some learning difficulty at school (identified here); adults able to work + maintain good social relationships + contribute to society
• Adequate language + social + self-care skills
• Difficulties in academic work
• Most live indep. → some need support in housing + employment

Question 8

Moderate mental retardation

Answer 8

• IQ 35-49 (Mental age: 6-9)
• Language limited (but still can communicate)
• Supervision for self-care but able to do simple work

Question 9

Severe mental retardation

Answer 9

• IQ 20-34 (Mental age: 3-6)
• Marked degree of motor impairment
• Little or no speech (early childhood) → may eventually have simple comm.
• Associated physical disorders

Question 10

Profound mental retardation

Answer 10

• IQ <20 (Mental age: <3)
• Severe motor impairment
• Severe difficulties in communication
• Little or no self-care
• Usually require residential care

Question 11

Aetiology LD

Answer 11

Genetic eg Downs
Antenatal eg congen infection such as rubella
Perinatal eg IVH
Neonatal eg meningitis
Postnatal eg CP

Question 12

Genetic causes LD

Answer 12

• Autosomal chromosome disorders → Down’s
• X linked syndromes →
o X linked dominant syndromes: Fragile X syndrome, rett’s syndrome, Aicardi syndrome
o X linked recessive syndromes: Hunter syndrome, Lesch-Nyhan syndrome, oculocerebrorenal syndrome of Lowe,
• Deletions + duplications → Prader-Willi syndrome (partial deletion Chromosome 15), Cri du chat (partial deletion chromosome 5), Angelman syndrome, beta thalassaemia mental retardation, DiGeorge syndrome, Rubenstein-taybi syndrome, Smith-Magenis syndrome, Williams syndrome, Wolf-Hirchhorn syndrome
• Autosomal dominant conditions → Noonan’s syndrome, tuberous sclerosis, neurofibromatosis T1 (chromosome 17), neurofibromatosis T2 (chromosome 22), sturge-weber syndrome, Von Hippel-Lindau syndrome [renal carcinoma!!!]
• Autosomal recessive conditions → Phenylketouria (chromosome 12; diagnosed at Guthrie test), sanfilippo disease, Hurler syndrome, Laurence-Moon syndrome, Joubert syndrome, gaucher’s disease
• Presumed polygenic conditions → neural tube defects, pervasive developmental disorders
• Mitochondrial disorders [maternally inherited] → myoclonic epilepsy w/ ragged red fibres
• Sex chromosome disorders → turner’s syndrome (one X chromosome, female phenotype), trisomy X, klinefelter’s syndrome, XYY male

Question 13

Antenatal causes LD

Answer 13

Congenital infection (rubella, CMV, toxoplasmosis)
nutritional def
intoxication (alcohol, cocaine, lead)
endocrine disorders (hypothyroidism, hypoparathyroidism)
physical damage (injury, radiation, hypoxia)
antepartum haemorrhage
pre-eclampsia

Question 14

Perinatal causes LD

Answer 14

Birth asphyxia
intraventricular haemorrhage
neonatal sepsis

Question 15

Neonatal causes LD

Answer 15

Hypoglycaemia
meningitis
neonatal infections
kernictus (due to hyperbilirubinaemia)

Question 16

Postnatal causes LD

Answer 16

Cerebral palsy
infection (meningitis, encephalitis)
anoxia
metabolic (congenital hypothyroidism, hyponatraemia)
iodine def.

Question 17

Environmental causes LD

Answer 17

Neglect
NAI (non-accidental injury)
malnutrition
socioeconomically deprived

Question 18

Psychiatric causes LD

Answer 18

Autism

Rett’s syndrome (genetic disorder affecting brain development [seizures!!])

Question 19

CFs LD

Answer 19

• Common physical problems: motor (e.g. ataxia, spasticity), epilepsy, impaired hearing/vision, incontinence
• See each severity (in criteria section)

Question 20

Dx + Ix LD

Answer 20

Establishing cause:
• Hx → FH, Gestational Hx, birth Hx, neonatal hx, childhood Hx (inc. developmental milestones)
• Physical examination: dysmorphic features, developmental exam…etc
• Ix
o Standard: FBC, U+Es, LFTs, TFTs, glucose, infection screening (blood + urine), serology (CMV, toxoplasmosis…)
o If dysmorphic features → XR skull…etc
o Metabolic disorder suspected → screening (blood + urine)
o If genetic disorder suspected: karytoping
o Other: neurophysiological test (EEG), neuroimaging…etc

IQ test!!!!

Question 21

Treatment LD

Answer 21

• MDT approach → GP (physical health problems), psychiatrist, SALT, specialist nurses, psychologist, OT, social worker, teachers
• Antipsychotics → challenging behaviour
• Behavioural techniques → applied behavioural analysis, +ve behaviour support, CBT
• Family education

Question 22

Prevention

Answer 22

Genetic counselling + antenatal diagnosis

Question 23

Down’s syndrome - pathophysiology / aetiology + RFs

Answer 23

• Trisomy 21
• Maternal age >40
• Previous child w/ T21
• T21 in mother

Question 24

CFs Down’s - physical features

Answer 24

Physical features (PROBLEMS)
• Palpebral fissure
• Round face
• Occipital + nasal flattening
• Brushfield spots (on iris) + brachycephaly
• Low-set small ears
• Epicanthic folds
• Mouth open + protruding tongue (small mouth)
• Strabismus (squint), sandal gap deformity, single palmar crease
• Also: short stature, overweight

Question 25

CFs Down’s - medical problems

Answer 25

• Congenital heart defects (VSD, ASD, mitral valve disease, PDA, ToF)
• Congenital GI abnormalities (oesophageal atresia, duodenal atresia, Hirschsprung’s, coeliac)
• Hypothyroid
• Haematological malignancies (AML, ALL)
• Alzheimer’s disease
• Others: sensorineural deafness…etc

Question 26

CFs Down’s - psychiatric problems

Answer 26

• Depression
• Learning disability
• Less common: BPAD, OCD, tourette’s, schizophrenia, ^ risk of autism

Question 27

Investigations Down’s

Answer 27

During pregnancy:
o EITHER → serum screening (beta-hCG + pregnancy-associated plasma protein A) and nuchal translucency on USS
o OR → Quadruple testing: beta-hCG, alpha-fetoprotein, inhibin A, estriol

Question 28

What is Fragile X syndrome?

Answer 28

• 2nd commonest cause of LD
• M>F (due to protective effects of second normal X chromosome in females)
• Variable LD (mild → profound)

Question 29

Pathophysiology fragile X syndrome

Answer 29

X-linked dominant transmission

Question 30

CFs fragile X syndrome - behaviour

Answer 30

Behaviour (similar to autism): hand flapping/waving, repetitive mannerisms, shyness, gaze avoidance, poor peer relationships, perseveration, echolalia (meaningless repetition of another person’s spoken words), palilalia (involuntary repetition of words, phrases or sentences), over detailed speech

Question 31

CFs fragile X syndrome - physical & medical

Answer 31

• Large testicles + ears
• Smooth skin
• Hyperextensible fingers
• Flat feet
• Mitral valve prolapse
• Inguinal + hiatus hernia
• Facial: long, narrow face w/ underdevelopment of mid-face, macrocephaly
• Epilepsy
• Psychiatric problems: depression + anxiety

Question 32

Ix fragile X syndrome

Answer 32

Brain imaging → reduced posterior cerebellar vermis, enlarged hippocampus + causate nuclei, enlarge ventricles