Learning Disability

Question 1

What is a learning disability (LD)?

Answer 1

Learning disability (LD) is a state of arrested or incomplete development of the mind.

It is characterised by impairment of skills manifested during the developmental period and skills that contribute to the overall level of intelligence.

Question 2

Briefly differentiate between mild, moderate, severe and profound LD

Note: all in ICD-10 Classisication

Answer 2

Mild → IQ = 50– 70 (mental age = 9– 12)

Moderate → IQ = 35– 49 (mental age = 6– 9)

Severe → IQ = 20– 34 (mental age = 3– 6)

Profound → IQ = <20 (mental age <3 years)

Question 3

What is the triad of LD?

Answer 3

A triad must exist to constitute a learning disability. This includes:

1. Low intellectual performance (IQ below 70)
2. Onset at birth or during early childhood
3. Wide range of functional impairment including social handicap due to reduced ability to acquire adaptive skills (activities of daily living)

Question 4

Briefly describe the genetic pathophysiology and aetiology of LD

Answer 4

Down’s syndrome, fragile X syndrome, Cri du chat, Prader– Willi, neurofibromatosis, tuberous sclerosis, Angelman syndrome, homocystinuria, galactosaemia (carbohydrate), phenylketonuria (protein), Tay– Sachs disease (lipid) and hydrocephaly.

Question 5

Briefly describe the antenatal pathophysiology and aetiology of LD

Answer 5

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

Question 6

Briefly describe the perinatal pathophysiology and aetiology of LD

Answer 6

Birth asphyxia, intraventricular haemorrhage and neonatal sepsis.

Question 7

Briefly describe the neonatal pathophysiology and aetiology of LD

Answer 7

Hypoglycaemia, meningitis, neonatal infections and kernicterus.

Question 8

Briefly describe the postnatal pathophysiology and aetiology of LD

Answer 8

Infection (e.g. meningitis, encephalitis), anoxia, metabolic (e.g. hypothyroidism, hypernatraemia) and cerebral palsy.

Question 9

Briefly describe the environmental pathophysiology and aetiology of LD

Answer 9

Neglect/non-accidental injury, malnutrition and socioeconomically deprived.

Question 10

Briefly describe the psychiatric pathophysiology and aetiology of LD

Answer 10

Autism and Rett’s syndrome.

Question 11

How common is LD?

Answer 11

The prevalence of LD is 2%:

• 85% of these are mild
• 10% moderate
• 5% severe or profound

Question 12

Are LD more common in men or women?

Answer 12

The ♂ to ♀ ratio is 3:2.

Question 13

What is the biggest risk factor for a LD?

Answer 13

The most common risk factor is a positive family history of LD.

Question 14

What are the common physical disorders linked to LD?

Answer 14

Common physical disorders include motor disabilities (e.g. ataxia, spasticity), epilepsy, impaired hearing and/or vision and incontinence (faecal and urinary).

Question 15

How does mild LD present?

Answer 15

Usually identified at a later age when the child starts school. They have adequate language abilities, social skills and self-care . There may be difficulties in academic work. Most live independently but may need some support in housing and employment.

Question 16

How does moderate LD present?

Answer 16

Able to communicate but language is limited . May need supervision for self-care but able to do simple work.

Question 17

How does severe LD present?

Answer 17

There is a marked degree of motor impairment . Little or no speech in early childhood but may eventually use simple communication. May be able to perform simple tasks under supervision. They may have associated physical disorders.

Question 18

How does profound LD present?

Answer 18

Severe motor impairment and severe difficulties in communication. Have little or no self-care. Frequently have physical disorders and require residential care.

Question 19

What is Down’s syndrome?

Answer 19

Down’s syndrome: A genetic disorder (trisomy 21) characterized by LD, dysmorphic facial features and multiple structural abnormalities. It is the commonest cause of LD.

Question 20

What are the physical features of Down’s syndrome?

Answer 20

Physical features (‘ PROBLEMS ’):

• Palpebral fissure (up slanting)
• Round face
• Occipital + nasal flattening
• Brushfield spots (pigmented spots on iris)/ Brachycephaly
• Low-set small ears,
• Epicanthic folds
• Mouth open + protruding tongue
• Strabismus (squint)/ Sandal gap deformity/ Single palmar (Simian) crease

Question 21

What are the medical features of Down’s syndrome?

Answer 21

Heart defects (ventricular and atrial septal defects, ToF), hearing loss, visual disturbance (cataracts, strabismus, keratoconus), GI problems (oesophageal/duodenal atresia, Hirschsprung’s, coeliac), hypothyroidism and haematological malignancies (AML, ALL) and increased incidence of Alzheimer’s.

Question 22

What is Fragile X syndrome?

Answer 22

The second most common cause of LD. A sex-linked disorder with developmental, physical and behavioural problems.

Question 23

What are the physical features of Fragile X syndrome?

Answer 23

Large, protruding ears, long face, high arched palate, flat feet, soft skin and lax joints.

Question 24

What are the medical features of Fragile X syndrome?

Answer 24

Mitral valve prolapse.

Question 25

What is Prader-Willi?

Answer 25

Due to a deletion of part of chromosome 15. Characterised by hypotonia and developmental delay as an infant, and obesity, hypogonadism and behavioural problems (compulsive eating, disruptive behaviour) in later years.

Question 26

What is Cri du chat?

Answer 26

Caused by a partial deletion of chromosome 5. Those affected have a high-pitched cry like a cat. Low birth weight and feeding difficulties are also characteristic.

Question 27

Briefly describe the MSE of LD

Answer 27

Appearance will vary depending on the cause of learning disability, for example the type of genetic disorder.

The extent of behaviour problems is determined by the level of LD. In more severe cases there may be motor impairment. There is often speech disturbance and mood can be low or normal.

Question 28

What examinations should be performed for LD?

Answer 28

Examinations to be performed:

• Cardiovascular
• Respiratory
• Neurological (cranial nerves and peripheral)
• Weight, height and head circumference
• Developmental assessment

Question 29

What other psychiatric conditions are co-morbid with LD?

Answer 29

The following psychiatric disorders are more common in patients with learning disability:

• Early-onset Alzheimer’s disease
• Schizophrenia
• Anxiety and depressive disorders
• Autism
• Hyperkinetic disorder
• Eating disorders
• Personality disorders

Question 30

Who is involved in the MDT of LD?

Answer 30

• Community Learning Disability Nurses (CLDN)
• Speech and Language Therapist (SALT)
• Occupational Therapist (OT)
• Physiotherapist (PT)
• Clinical psychologist
• Care managers and carers
• Teachers

Question 31

How can communication with a patient with LD be maximised?

Answer 31

Always greet the patient before greeting the accompanying individual and ensure communication is clear with simple language used.

Give appropriate time for the patient to respond.

Use gestures or pictures to explain your point if they struggle to understand.

Note: focus on their abilities not their disabilities.

Question 32

What investigations should be ordered for LD?

Note: before and after birth

Answer 32

Before birth

• Amniocentesis, chorionic villus sampling, genetic testing and karyotyping
• For Down’s syndrome there are two methods:
  
  • Serum screening (β-hCG and pregnancy-associated plasma protein A) + nuchal translucency
  • Quad test (β-hCG, α-fetoprotein, inhibin A, estriol)

After birth

• Bloods:
  
  • FBC (infection)
  • TFTs (hypothyroidism)
  • Glucose (hypoglycaemia)
  • Serology (ToRCH infections)
• Brain imaging: CT head and/or MRI
• IQ (intelligence quotient) test

Question 33

What is the role of the GP in treating a LD?

Answer 33

The GP must be involved in the care of the individual as physical health problems are common. Treatment of co-morbid medical conditions and psychiatric problems is vital.

Question 34

Briefly describe the treatment of a LD

Answer 34

Antipsychotics can be used for challenging behaviour but are overused.

Behavioural techniques such as applied behavioural analysis, and positive behaviour support, as well as CBT can be used. Psychiatrists, mental health nurses and psychologists can support carers with these strategies.

Family education is essential and support should be offered through educational programmes and voluntary organizations.

Question 35

How can LD be prevented?

Answer 35

Prevention can be attempted through genetic counselling and antenatal diagnosis.