Nutrition, constipation and dehydration Flashcards
Daily fluid requirements (>6months)
1,500ml/m2/day by surface area
Or by weight - 1st 10kg - 100ml/kg/day –> 2nd 10kg 50ml/kg/day –> each further kg 20ml/kg/day
Daily fluid requirements (<6months)
Term (1-3months) - 150ml/kg/day
Preterm (<32weeks) - 200ml/kg/day
Benefits of breast feeding (6)
Ideal nutritions, immunoglobulins & leukocytes, low risk of infection or incorrect mixing. Emotional bonding, oxytocin release, lower risk of obesity/atopic disorders, better neurodevelopmental performance and emotional stability
Breast milk vs Cows milk
Slightly less energy except in colostrum
More protein, IgG, Casein, less lactose and fat,
Much more ions
Diarrhoeal dehydration (2,5,1)
The biggest killer of babies globablly. Viral - Rotavirus, Norovirus and others. Bacterial - campylobacter, shigella/salmonella/Enteropathogenic E coli or cholera
Protozoal - Cryptosporidium
Mild Dehydration
Up to 5% weight loss
Hx of diarrhoea and vomiting, – no/minimal physical signs
Skin turgor and fontanelle tension is normal
Extremities are warm
Moderate Dehydration
5-10% weight loss - Signs of contraction of interstitial fluid
Reduced skin turgor, depressed fonanelle, sunken eyes but circulation is maintained
Severe Dehydration
10-15% weight loss - Signs of contraction of interstitial fluid and circulatory compromise. Reduced skin turgor, depressed fonanelle, sunken eyes and tachycardia, weak peripheral pulses, delayed cap refill, cold extremities (central/peripheral temp gap >2C)
Types of dehydration
Defined by ECF tonicity:
Isotonic - plasma Na 130-150mmol/L
Hypertonic - plasma Na >150mmol/L
Treatment of deydration
Restore the ECF volume with isotonic fluid
Replace K+ and alkali – give K+ and bicarbonate
Maintain nutrition – give local starch staple (polymer base)
Do not interrupt breast feeding
WHO oral rehydration solution
3.5g salt 2.5g baking soda
1.5g KCl 20g sugar
In 1L of water - if using polymer base replace sugar with 30g of ground rice
IV rehydration
Used when oral rehydration has failed in moderate to severe dehydration — use isotonic solution and be careful about replacing hypernatreamia too quickly
Re-establish feeding as soon as possible
Causes of acid/base imbalance in children
Respiratory acidosis - CO2 retention in bronchiolitis
Respiratory alkalosis - hyperventilating
Metabolic acidosis - ketoacidosis in diabetes
Metabolic alkalosis - loss of HCl due to pyloric stenosis
Infantile hypertrophic pyloric stenosis
Due to fibromuscular hypertrophy of the pylorus - palpable as an olive mass below the right costal margin. Causes projectile vomiting from the 1st wk upto 2months. More in boys and first borns – can lead to FTT. Vomit is never bile stained and HCl is lost
Diagnosis of pyloric stenosis
USS is diagnostic but can also feel an ‘olive tumor’ during test feed - may be a family history. Persistent jaundice
May be visible peristalsis from left–>right across abdomen
Treatment of pyloric stenosis
Replace fluid with saline + 20mmol K+
Definitive treatment is longitudinal division
(Ramstedt’s pyloromyotomy)
Diabetic ketoacidosis
Metabolic acidosis due to production of ketones from fats to replace sugars which cannot enter cells due to lack of insulin - smell of acetone
Why are children dehydrated during ketoacidosis?
Hyperglycaemia increases ECF osmolality which causes some water loss from cells (idiogenic osmols defend cell volume) –> hyperglycaemia causes osmotic diuresis causing dehydration and hyponatraemia
Signs of ketoacidosis
Impaired consciousness. Ketotic (acetone) breath. Kussmaul’s breathing (deep sighing). Will be acidotic, Low HCO3, hyperglycaemic, hyponatraemic, hypokalemic
Treatment of ketoacidosis
Treat shock and restore fluid volume with saline (with K+)
Gently lower glucose with small doses of insulin
Do not give alkali and beware rapid changes in osmolality as this can cause cerebral oedema
Other causes of acid/base imbalance
Burns
Acute or chronic renal failure
Diabetes insipidus or psychogenic polydipsia
Congenital adrenal hyperplasia
Epidemiology of Constipation
3% of general paediatric and 25% of paediatric gastro clinics
prevalence 0.3-28% in vulnerable periods
Vulnerable periods for constipation
Infants: after the introduction of solid foods and weaning onto solid foods. Toddlers: at the time of potty training
Older children: avoiding the bathroom at school
Definition of functional constipation in Infants (<4yrs)
1/12 with 2 of: 1wk of incontinence after potty training, Hx of retention with painful and large poos with feeling of fecal mass in rectum, accompanying symptoms (irritability, decreased appetite, early satiety)
Definition of functional constipation in Infants (>4yrs)
2/12 with 2 of: 1wk of incontinence after potty training, Hx of retention with painful and large poos with feeling of fecal mass in rectum, accompanying symptoms (irritability, decreased appetite, early satiety)
Disorders of defecation
Infant dischezia
Constipation
Retentive incontinence
Non-retentive incontinece soiling
Physiology of defecation
rectal distention -> the external anal sphincter (EAS) and puborecalis (PR) contract and the internal AS (IAS) relaxes –> Defecation Urge-> If appropriate EAS and PR relax and you poo-> if not EAS and PR remain contracted and IAS recovers tone and defecation urge passes
Stool withholding cycle
previous painful experience prevents children passing stools which leads to rectal distension > eventually this forms a faecal mass around which liquid stool seeps causing overflow incontinence > distension reduces rectal sensitivity leading to the loss of normal defecation urge
Causes of constipation in infants
Intestinal obstruction, Hirschsprungs disease, Ano-rectal anomalies (agensis, myelocele), Cystic fibrosis, Functional fecal retention
Causes of functional non-retentive fecal incontience
IBS Coeliac disease
Myopathies
Other metabolic or endocrine disorders, lead poisoning
Drugs – opiates or antacids
How to assess constipation in a child - History
Did they pass meconium? Age of onset, consistency and size of stools
Associated symptoms –> pain, blood, Holding posture. Functional constipation risk period/possible causes. Is there incontinence or overflow diarrhoea? Diet and toilet training
How to assess constipation in a child - Exam
Gen. growth and abdomen (size and masses)
Anal – position, fissures?, redness, signs of abuse, soiling
PR – tone, sensation, presence and quality of stool
Lumbo-sacral dimple with tuff of hair (spina bifida occulta)
Red flags for constipation
Onset <12months – delayed passage of meconium
No soiling, FTT, Empty rectum, tight anal sphincter
Abnormal neurology and lumbo sacral anatomy
Extra-intestinal symptoms, bladder symptoms, blood in stool
Infant dischezia
When healthy infants strains and cries to pass soft stools —> abdomino-pelvic dyssynergia
Treat with reassurance
Hirschsprung’s disease
Lack of nervous innervation of the large bowel
can present from birth into childhood
Diagnostics for constipation
History and exam are most important
AXR, Barium enema or CT
Can use colonic or anorectal manometry
Sweat test if CF is suspected
Treatment of constipation
Improve dietary fluid and fiber –> if not able to pass stools evacuate with senna or manually. Give parallel psychological help
Can also use osmotic and stimulant laxatives, also lubricants and bulking agents. Movicol is 1st line in kids
Causes of dehydration (3)
Gastroenteritis and diarrhoea (biggest for children)
Diabetes
Intestinal obstruction leading to vomiting
Homeostatic regulation of body fluid
Osmolarity and fluid volume are closely related
At first osmolarity is prioritised —> when volume drops significantly this reverses
Controlled by ADH, distal renal tubules, aldosterone
Acute diarrhoea & vomiting - causes
Usually in children under 2yrs in the winter
Aetiology: 60% viral, 15% bacterial, 1% protozoan, idiopathic 24%
Differential –> meningitis, DKA, appendicitis, Intussusception
Acute diarrhoea & vomiting - presentation
D&V , abdo distension and pain, watery stools, mild fever
may have URTI prodrome
if invasive bacterial gastroenteritis
bloody mucoid stools –> show be treated with abx
May also have high fever, iritability, convulsions, erythema nodosum and arthritis
In most cases of gastroenteritis antibiotics are…
CONTRAINDICATED because there is a risk of toxicity
and the slow gut transit time which encourages abnormal bowel flora
Fluid deficit in dehydration
If shock treat with 20ml/kg boluses
Deficit is kg x % dehydration x 10
Aim to replace deficit over 24-48hrs
Morbidity of dehydration
Early - Oliguria and renal failure, convulsions, pulmonary odema
Late - protracted diarrhoea due to persistent reinfection
Mortality: 6/100,000 in under 5s with gastroenteritis
8% of surviving infants have neurological deficits
Causes of chronic diarrhoea in children
Well children - toddler’s or non-specific
Malabsorption – cystic fibrosis, Coeliac, lactose intolerance
Infection - giardia lamblia
Inflammatory - crohn’s, cow milk protein intolerance, UC
Toddler’s diarrhoea
Non-specific diarrhoea in a healthy toddler, especially if there is loose stools with undiagested food. May be linked to a large fluid intake or just rapid transit.
Coeliac disease
Gluten intolerance which will present before 2yrs with FTT, anorexia, abdo pain/distension, vomiting & diarrhoea and buttock wasting. stools will be pale and foul smelling. gluten free diet and rechallange after 2yrs. 95% are HLA DQ2
Secondary lactose intolerance
Occurs secondary to Gastroenteritis where the surface mucosal cells with lactose have been stripped away. congential intolerance is rare. switching to soy or breast milk for a period is often enough
Cow milk protein intolerance
Rare, diarrhoea may be bloody with urticaria/eczema, stridor and wheeze. presents in first 3months. Less common in breast fed babies. switched to hydrolysed formula and rechallanged over a period of time. Usually resolves within 1-2yrs
Giardia lamblia
Causes outbreaks of watery diarrhoea with weight loss and abdo pain in playcentres. may follow foreign travel. treat with metronidazole.
kwashiorkor
A form of severe protein-energy malnutrition characterised by oedema, abdominal distension, irritability, anorexia & fatty liver enlargement. this occurs in cases of sufficient calories but insufficient protein. May also have thinning or discoloured hair, loss of teeth and skin depigmentation.
Marasmus
A severe form of calorie deficiency characterised by emacited appearance (<60% of expected body weight). May be fretful, irritable and extremely hungry
