Paediatric nutrition [advanced]

Background knowledge

Assessing nutritional status

• Plot height and weight on growth charts (determine trend and centiles)
• History and examination
• Bloods: haemoglobin, electrolytes (including Mg, PO, Ca), LFTs (including albumin), haematinics (B12, folate, ferritin)

Normal requirements

Nutrient	Neonate/Infant	Children 2-12 years	Adolescent
Energy kcal/kg/day	80-100	60-80	30-40
Protein g/kg/day	1.2-1.8	1	0.8
Fluid ml/kg/day	100 for 1st 10 kg, 50 for 2nd 10kg, 20 for remainder	100 for 1st 10 kg, 50 for 2nd 10kg, 20 for remainder	100 for 1st 10 kg, 50 for 2nd 10kg, 20 for remainder

Matching requirements

• Most formulas contain 0.6-1 kcal/ml and are nutritionally complete
• The volume of formula required must be calculated by working out their requirements 
• Daily volume required (ml) = daily requirement (kcal) / formula concentration (kcal/ml)

Age progression

• Breast milk is ideal for most infants
• Weaning on to solids should occur at 6 months
  • Initially baby rice, fruit and vegetables, then progress tastes and textures
  • Finger food from 7 months
• Complimentary breast or formula milk should continue until 1 year, then full fat cow’s milk should be main drink (semi-skimmed from 2 years)
• Supplemental vitamins A, C and D until 5 years
• Older children: whole-grain cereals; 5-a-day vegetables/fruit; 2 servings of meat or alternatives per day; 1 starchy food at each meal time; 3-4 portions of dairy product per day

Formulas

• Standard milk-based
  • Examples: aptamil, SMA first, Enfamil, cow & gate, babynet, alpro, hollie

Protein variations (for dietary protein intolerances)

• Soy formulas
  • Still whole protein but different type
  • Not first line because up to half of babies with cow’s milk protein intolerance are also intolerant to soy protein
  • Examples: infasoy, wysoy
• Partially-hydrolysed
  • Available over the counter
  • Examples: aptamil comfort, cow & gate comfort, SMA comfort
• Extensively-hydrolysed
  • 1^st line for dietary protein intolerances
  • Examples: nutramigen 1, pepti junior, aptamil pepti, infatrini peptisorb
• Elemental (amino-acid based)
  • 2^nd line for dietary protein intolerances
  • Very expensive
  • Examples: neocate LCP, nutramigen AA

Carbohydrate variations (for carbohydrate intolerances)

• Lactose-free
  • Examples: enfamil o-lac, SMA LF

Fat variations (for fat absorption disorders)

• Medium chain triglyceriedes (MCT)
  • Examples: portagen powder
• Light chain triglyceriedes (LCT)

Viscosity variations (for reflux)

• Thickened
  • Examples: SMA stay down, enfamil AR (anti-reflux), aptamil AR

High energy variations (for catch up growth)

• High energy
  • Examples: infatrini, SMA high energy

Enteric feeds

When oral feeds cannot sustain adequate growth and the gut is functioning, formula milk, expressed breast milk or enteral feeds can be administered via tubes…

Administration methods

• Fine bore-nasogastric (NG) tube – default
• Nasojejunal (NJ) tube – if problems with gastric reflux or delayed gastric emptying
• Percutaneous gastrostomy/jejunostomy tube – for longer term feeding i.e. >4-6 weeks or if mechanical swallowing obstruction

Administration

• Boluses – more physiological but can cause ‘dumping syndrome’
• Intermittent infusion – most commonly used (e.g. 10 hours on, 2 hours off)
• Continuous infusion – used for very ill patients

Drugs down enteric tubes

• Use solutions where possible
• Some tablets can be crushed and some capsules may be opened (check with pharmacist)
• Tablets which cannot be crushed: modified release tablets; enteric coated tablets

Parenteral nutrition

Parenteral nutrition may be required in intestinal failure (acute or chronic) and is given via central venous access

• ‘Parenteric nutrition’ (PN) – if also feeding patient by other methods
• ‘Total parenteric nutrition’ (TPN) – only IV feeding

Re-feeding syndrome

• Insulin surge and re-switching on of cellular membrane pumps in response to feeding causes electrolyte abnormalities (especially K⁺, PO₄^3-, Mg²⁺) which can lead to arrhythmias and death
• Check K⁺, PO₄^3-, Mg²⁺
• Prevent by starting feed slowly in at risk patients
• Management
  • Continue low level of feed
  • Daily bloods minimum initially
  • Replace all electrolytes – see common prescriptions

Causes of faltering growth

Low intake

• Not enough food offered or taken (95% of cases)
• Psychological
• Structural
• Neurological

Food loss

• GORD
• Pyloric stenosis
• Dysmotility

Increased requirements

• Cystic fibrosis
• Congenital heart disease
• Malignancy

Malabsorption – Digestive

• Carbohydrate ‘intolerance’ (lack of enzymes mean undigested disaccharides increase osmotic load causing flatulence, bloating, diarrhoea and cramps after eating carbohydrate)
  • Lactose intolerance
    • Congenital lactase deficiency (rare)
    • Secondary to enterocyte damage after gastroenteritis (transient)
  • Maltose intolerance
  • Sucrose intolerance
• Pancreatic
  • Cystic fibrosis
  • Chronic pancreatitis
  • Cholestasis

Malabsorption – Mucosal

• Dietary protein ‘intolerance’ (allergy to certain proteins)
  • Cow’s milk protein allergy (presents in first few months after being fed with formula)
  • Soya bean protein allergy
  • Egg protein allergy
• Coeliac disease (presents any time after weaning with bloating, diarrhoea, failure to thrive)
• Inflammatory bowel disease
• Abetalipoproteinemia (autosomal recessive mutation in microsomal triglyceride transfer protein resulting in interference with fat and fat-soluble vitamin absorption)
• Intestinal venous/lymphatic obstruction (e.g. cardiac failure, lymphangiectasia)