JC120 (Paediatrics) - Child early growth and nutrition

Question 1

Key determinants of growth during infancy, young childhood and puberty

Answer 1

Fetal stage/ infancy – nutrition = single most important factor

Young childhood – growth hormones, thyroid hormones

Puberty – sex hormones

Question 2

Physiological factors that limit infant digestion and nutrition

Answer 2

Neonatal GIT is underdeveloped:

1. Uncoordinated sucking and swallowing
   - Poor esophageal motility
   - Poor LES tone and frequent reflux
2. Delayed gastric emptying
3. Disorganized intestinal motility: rapid emptying of ileum and colon limits water and electrolyte absorption, risk of dehydration
4. Less GIT secretions for digestion (salivary, pancreatic, gastric, HBP…)
5. Immature kidneys unable to expel undigested waste products

Question 3

Describe how the fetal GIT develops for nutritional uptake

Answer 3

Fetal GI tract is exposed to constant passage of fluid that contains Growth factors, Hormones, Enzymes, Immunoglobulins
»> transitional changes to support growth of GI tract:
 Mucosal differentiation, GI development
 Development swallowing, intestinal motility

Gut hormones also causes GIT to mature

Question 4

Describe how immature kidney function influences neonatal nutrition

Answer 4

Immature nephrons and pituitary gland in neonates = cannot concentrate urine and process high solute loads

> > Selection of food with Low potential renal solute load is better than high renal solute load

Human milk (= best, lowest burden) 
Whole cow milk (= highest solute load, do not give)

Question 5

Factors that changes amount of gut hormones in neonates

Answer 5

• Elevated in fetal distress for passage of meconium (meconium-stained liquor; MSL)
• Enteric intake of food&raquo_space; induce epithelial hyperplasia, stimulate microvillous enzymes production
• Early enteral feeding and breastfeeding increases GIT hormone expression

Question 6

Role of gut hormone in neonatal GIT development

Answer 6

1) Gut motility - Motilin
2) Tropic to gut mucosa - Enteroglucagon

3) Intestinal mucosal and pancreatic growth
 Enteroglucagon
 Gastrin
 Pancreatic polypeptides

4) Stimulus to insulin release - Gastric inhibitory polypeptide (GIP)

Question 7

Clinical assessment of nutritional deficiency in a baby

Answer 7

Signs: Cachexic appearance, marked wasting over buttocks, stunting, failure to thrive

Growth parameters:

• Body proportion: weight/height, +/- head circumference
• Growth record (compare with past)
• Comparison with other babies (relative to peers: age- and sex-appropriate)

Question 8

Key milestones of child growth

• Birth weight
• Weight trend
• Height
• Head circumference

Answer 8

Birth weight at term:
 3.2kg (F)
 3.4kg (M)

Weight:
 Double by 4 months (6-7kg)
 Triple by 10 months

Height:
 1⁄2 adult height by 3 years
 3⁄4 adult height by 9 years

Head circumference – 85% adult HC by 3 years

Question 9

WHO criteria for child growth failure

- Underweight, stunting and wasting

Answer 9

1. Underweight = Z-score cut-off point of

Question 10

Failure to thrive

• Clinical definition

Answer 10

Definition (= medical diagnosis):
 Failure of expected growth in children younger than 3 years
 Downward crossing of two percentile lines in weight over 6 months

Question 11

Outline groups of causes of failure to thrive

Answer 11

Poor processing of nutrition:

• Inadequate calorie intake
• Abnormal digestion/ malabsorption
• Inability to process calories - Syndromal genetic diseases/ Metabolic disorders
• Excessive loss

Increased calorie requirement/ abnormally high calorie requirement

Question 12

Causes of inadequate calorie intake in a neonate/ child

Answer 12

Maternal Factors: 
 Failed breastfeeding
 Inappropriate feeding technique
 Wrong formula
 Poor preparation (misconception/ tradition)

Child factors:
 Congenital anomalies (e.g. cleft palate)
 CNS disorders (e.g. swallowing problem)
 Distress (due to cardiopulmonary conditions)
 GI – vomiting, GER (reflux)

Question 13

Causes of malabsorption in a neonate/ child

Answer 13

Primary: Uncommon (e.g. cystic fibrosis)

Secondary:
 Post-gastroenteritis (common): secondary disaccharidase deficiency  meal intolerance
 Necrotising enterocolitis (NEC) – premature baby
 Short gut syndrome (due to surgical resection of ischemic bowel)
 Food allergy/ intolerance

Question 14

Causes of defective calorie processing in a neonate/ child

Answer 14

Syndromal diseases - e.g. Down syndrome

Metabolic disorders:
 Inborn errors of CHO metabolism
 Aminoacidopathies
 Mitochondrial diseases

Question 15

Causes of increased caloric requirement in an infant/ neonate

Answer 15

 Chronic/ recurrent infection – urinary tract infection, tuberculosis
 Chronic respiratory insufficiency – bronchopulmonary dysplasia (BPD), CF (Caucasians)
 Congenital/ acquired heart disease
 Chronic anemia
 Malignancy
 Toxins – lead
 Drugs excess – thyroxine
 Endocrine disorders – hyperthyroidism (high metabolic rate)

Question 16

Physiology of milk expression during breastfeeding

Answer 16

Baby sucks nipple: stimulates nerves in breast via autonomic nervous system to hypothalamus:

1. Inhibit release of dopamine (reduce tonic inhibitory effect)&raquo_space; lactotrophs in anterior pituitary free to express its
   inherent capacity&raquo_space; secrete prolactin at a very high rate (lacteal glands produce milk for next feed)
2. Produce and transport oxytocin to posterior pituitary gland&raquo_space; act on myoepithelial cells (contract to eject
   milk for this feed)

Question 17

Nutrients contained in breast milk

Answer 17

Energy: 67 kcal/100ml

Nutrients:
 Carbohydrates – lactose, oligosaccharides
 Proteins – LF (lactoferrin), α-lactalbumin, b-casein, lysozyme; cytokines, antibodies…
 Fat – LC-PUFA (long-chain polyunsaturated fatty acid: DHA (docosahexaenoic acid), AA (arachidonic acid), EPA (eicosapentaenoic acid))
 Micro-nutrients (vitamins), trace metals (Fe, Ca)

Question 18

Benefits of breastfeeding to baby

Answer 18

 Nutritional value: best composition with high bioavailability

 Enzymes, hormones and immune factors

 Reduce obesity and overfeeding (breastmilk is tailor-made to need of baby at different stage)

 Less contamination, readily available

Offers unique immunologic protection:

1. Matches with sequence of postnatal development of immune system
2. Helps adaption of the gastrointestinal tract in the switch from fetal to postnatal life

Protects against infections & allergy – 3 overlapping groups of bioactive agents:

1. Direct-acting antimicrobial agents
2. Anti-inflammatory agents
3. Immunomodulating agents

Question 19

Benefits of breastfeeding to mother

Answer 19

 Involution of uterus
 Better physical shape
 Less neoplasm (breast cancer)
 Improves psychological well being
 Less postnatal depression

Question 20

Benefits of breastfeeding to family and society

Answer 20

Family:

• Maternal- infant bonding (attachment)
• Reduce withdrawal, behavioral problem and child abuse / neglect
• Contraceptive effect (for birth control)
• Most economic & effective way of feeding

Society:
 Less medical consultations
 Less hospitalizations
 Less medical expense related to infections

Question 21

Health risks associated with not breastfeeding to baby and mother

Answer 21

For baby:
 Diabetes: 40%
 Obesity: 25%
 Recurrent ear infection (otitis media): 60%
 Hospitalization for asthma/ pneumonia: 250%
 Death in first year: 27%

For mother:
 Maternal breast cancer: 39%
 Maternal type 2 diabetes: 14%/year

Question 22

Disadvantages/ Risks of breastfeeding to baby

Answer 22

 Infections – virus, e.g. HIV, CMV, HTLV (T-cell lymphoma)

 Transmission of undesirable drugs, e.g. chemo-, radiotherapy, psychiatric drugs

 Inborn error of metabolism – babies require special diet

Question 23

Disadvantage/ risks of breastfeeding to mother

Answer 23

 Physical exhaustion (frequent, on- demand feed)

 Emotional stress

 Impaired sleeping quality

Question 24

WHO recommendation for neonatal diet and breastfeeding period

Answer 24

Exclusive breastfeeding is recommended up to 6 months of age, with continued breastfeeding along with appropriate complementary foods up to 2 years of age or beyond

Question 25

Describe pancreatic function at birth and compensatory mechanisms for neonatal nutrition

Answer 25

Pancreatic function: relatively deficient at birth
Pancreatic enzymes (mature levels not achieved until late infancy)

Protein digestion:
- Gastric acid, pepsin, trypsin, chymotrypsin, pancreatic proteases, intestinal mucosal peptidases: all low level/ activity at birth

Carbohydrate digestion:

• Pancreatic amylase level is low until 4-6 months - Compensated by breastmilk amylase
• Disaccharidase level is normal - compensated by fermentation/ absorption in large intestines
• Lactase level is low until 3-5 years

Fat digestion:

• Pancreatic lipase is low until 1-2 years - compensated by lingual absorption, gastric absorption of breast milk
• Bile acid level is low until 6 months - compensated by bile-salt stimulated lipase