Paediatric Nutrition Flashcards
What is the aim of childhood nutrition?
the aim of nutrition in childhood is to match supply with demand so that full genetic potential can be expressed/reached.
prevent/treat malnutrition which, at this age, can have lifelong and transgenerational implications.
Describe some ways in which children are nutritionally vulnerable
High potential for imbalance between supply and demand:
demand is high because:
- growth rate
- high amount of metabolically active tissue
- disease/infection as immune system matured
- partitioning of nutrients between organs
supply can be low because:
- underdeveloped systems (absorptive, metabolic, excretory)
- illness (low appetite, increased losses)
- dependency on parents for food (SES)
Small nutrient stores = lower chance of survival in time of deprivation
Low capacity for reductive adaptation (the ability of body systems to shut down/do less to allow survival on limited calories)
Severe energy restriction in childhood may never be fully recoverable e.g., cognitive impairment & stunting.
Describe some characteristics of physical growth
- how does growth impact nutrient demand?
- why is measuring growth in paeds important?
Growth is regulated by both genetic, endocrine (hormone) and environmental factors
Growth encompasses changes in:
- body size and proportion
- body composition
e.g., development of skeletal muscle & tone
e.g., 0-6 months fat proportion increases from 14-25% which explains why growth is so energetically demanding at this age
- organ system maturation
- changes in chemical composition
- nutrition partitioning
e.g., Brain completes most growth in the first 2 years of life - glucose is the principal brain fuel so glucose requirements change greatly with age
Effect of growth on nutrient demand:
Growth is ‘expensive’
- in early years up to 50% of energy use can be attributed to growth
- partitioning of nutrients between organ systems (e.g., nutrients stored or oxidised for fuel) affects nutrient balance and requirement.
Why is measuring growth important?
- To identify malnutrition:
Growth follows a characteristic pattern which is disturbed if nutrition supply is inadequate, therefore, monitoring of growth throughout childhood is an essential clinical tool.
Describe some factors that can impact optimal growth in childhood
- what are some contributing factors to childhood malnutrition?
Socioeconomic status:
- poverty = under nutrition
- affluence = over nutrition
Ethnic background
General wellbeing e.g., underlying illness?
Physiological changes
- infancy
- puberty
What are some of the effects of nutrient restriction during childhood?
What mechanisms exist to counteract this?
Cognitive function
- Brain growth is completed in early years
- Prolonged and/or severe nutritional restriction at this age has severe consequences on lifelong functioning
Stunting:
- chronic early life undernutrition = stunting
- this also has impact on cognitive function:
At age 2, height > 2sd below WHO mean is associated with IQ deficit (although other factors may play a role)
Mechanisms exist to spare brain nutrition when intake is inadequate e.g., newborn suffering from intrauterine growth retardation is born with a large head and small body/limbs.
Describe what is meant be catch up and catch down growth in infancy.
Birth size predominantly determined by placental function and maternal nutrition.
Catch up growth:
Infant constrained within the intrauterine environment will thrive and seek out genetic potential if optimal nutrition is given outside of the womb
Catch down growth:
Over-nourishment within the intrauterine environment (e.g., diabetic mother) results in slowed growth after birth to reach genetically determined size.
Catch up and catch down growth are usually completed within the first year of life but can extend beyond 2 years.
Similar pattern is seen during puberty.
What are the key developmental changes that children to allow metabolic demand to be met?
- Development of GI system to enhance nutrient absorption
e.g., 24 weeks the gut is anatomically mature - Development of the liver and kidneys to enhance ability to adapt to over/under supply
- Neurological maturation to allow child to source own food supply
e.g., hand to mouth co-ordination and self-feeding
Describe metabolic maturation in children:
- what are the counter regulatory mechanisms that take place?
Newborns must quickly switch from continuous transplacental nutrient supply to intermittent enteral feeding
In the early days the energy provided by breastmilk is small (50-60ml) rising to 500-600ml
Counter regulatory mechanisms are developed to meet energy needs during this period of time:
- Adrenaline secretion opposed insulin action and stimulates lipolysis and protein catabolism to produce substrates needed for gluconeogenesis
- Growth hormone and cortisol secretion prevent neonatal hypoglycaemia.
How is the treatment of childhood undernutrition approached?
- what are the origins of undernutrition
- what aspects are included?
Treatment of undernutrition does not merely involve the provision of nutrients as the origin of under nutrition is complex:
- Physchological disturbance (ARFID?)
- SES (poverty)
- Physiological disturbance (illness)
Aspects of treatment includes:
- Societal level - wider availability of food e.g., providing free school meals
- Family level - parental education, free school meal vouchers, benefits
Individual level - underlying illness
What are the aspects of nutritional assessment in children?
History (medical & social)
- must be thorough
- must be taken by close relative or carer
Clinical examination
- anthropometry
- assess behaviour/temperament
- developmental stage e.g., puberty?
- full systematic evaluation (heart murmurs, stomach distension, muscle wasting?)
depending on the results of the above, some children may need further investigation which can include:
Special investigations
- assessment of nutrient balance
- assessment of body composition
- assessment of physiological & metabolic function
What are the UK recommendations for screening for malnutrition in children?
What difficulties can arise when screening for malnutrition?
Weighing of babies and children
- Once in first two weeks
- Monthly in first 6 months
- 6 months to 1 year - every 2 months
- 1 years + every 3 months
Interpretation of weight measurement can be difficult due to catch up/catch down growth.
Special indexes have been developed to differentiate between babies ‘failing to thrive’ and those experiencing catch down:
- Calculation of the thrive index and use of the thrive lines (1994)
explain what is meant by ‘failure to thrive’
- definition
- causes
- treatment
FTT is a common term used to describe lack of adequate weight gain in pediatric patients e.g., weight for age less than the fifth percentile on standardized growth charts.
FTT can have many causes, some which are concurrent e.g.,
- insufficient nutrient intake
- excess losses e.g., vomiting & diarrhoea
- abnormal nutrient partitioning
FTT is rarely due to underlying illness.
- insufficient nutrient intake is often a sign of neglect/abuse, or parenting difficulty such as poverty.
Factors leading to FTT in industrialised countries are non-organic and are related to inappropriate care practices or developmental delay.
other less common causes include:
- Chromosome abnormalities, such as Down syndrome
- Endocrine abnormalities such as hyperthyroidism or GH deficiency
- Gastrointestinal problems - malabsorption
Treatment of weight faltering is behavioural and directed at solving the root cause of FTT
Involves a multi-disciplinary approach including involvement of a paediatric dietitian.
Prescription of ONS is not appropriate - should be used only in cases of underlying illness where nutrition support is required.
Explain the prevalence and implications of severe malnutrition in children
What are the principles for assessment and screening of severe malnutrition in children?
Severe undernutrition in children is life threatening
Kwashiorkor (protein malnutrition)
Marasmus (protein-energy malnutrition)
Mostly occurs in developing countries due to famine or national emergency. Also occurs in industrialised countries e.g., anorexia nervosa.
Diagnosis
- Kwashiorkor or marasmus?
Assessment
- Assessment of body composition
- Wasting or stunting?
Treatment includes -
Resuscitation, Stabilisation & Repair:
- Fluid and electrolyte balance determines choice of feed given
- Underlying infection & micronutrient deficiency treated
- Hypoglycaemia & hypothermia must be addressed
Rehabilitation and repletion:
- Sufficient food to promote catch up
- Education for carers about refeeding
- Immunisation
Discuss micronutrient deficiencies in children
What are the most common?
what are the signs?
what are the underlying causes?
Micronutrient deficiency is common in children, in both developing and industrialised countries.
Most common:
- vit A (evidenced by xerophthalmia)
- vit D (evidenced by growth retardation, genu valgum/genu varum deformity)
- iron (evidenced by pallor)
- zinc (evidenced by acrodermatitis)
The underlying cause of micronutrient deficiency in children reflect the general nutritional vulnerabilities of children:
- low body store of nutrients
- low intake (due to poor diet)
- increased nutrient loss (recurrent infection due to underdeveloped immune system)
However, some micronutrient deficiencies occur due to geographical reasons (lack of mineral in soil).
Other deficiencies seen in special circumstances include:
- iodine
- selenium
- scurvy (vit C)
- B vitamins
How is obesity defined in childhood?
What are some of the issues associated with defining overweight/obesity in children?
Overweight is defined as:
BMI > 85th percentile (population monitoring)
Obesity is defined as:
BMI > 95th percentile (population monitoring)
BMI > 98th percentile = clinically obese
It is inappropriate to use BMI in the same way that it is used in adults.
BMI is read off charts specifically designed for boys and girls:
(charts are derived from WHO Multicentre Growth Reference Study & 1990 Growth Reference)
Issues with defining overweight/obesity in children include:
- long term implications of any given BMI are not clear - i.e., cut offs for clinical risk are difficult to determine
- charts are cross-sectional and children tend to move up and down centiles as they grow - not linear.
Systematic review and meta-analysis found that there is little relationship between childhood BMI and adult fatness however, there is a correlation between adolescent BMI and adult fatness (Simmonds et al, 2016)
