Gastroenteritis - Paediatrics

Gastroenteritis

Differential of acute vomiting/diarrhoea

·        Enteric infection:

o   Virus: rotavirus (45% of acute gastro), also enteric adenovirus, caliciviruses, astroviruses 

o   Bacteria: Campylobacter, Salmonella (more common spring/summer), also Yersinia, enterohaemorrhagic E coli, shigella

o   Protozoa: giardia, cryptosporidia, also microsporidia, amoeba 

o   Food poisoning: (had anything different to eat from the rest of the family?) Staphylococcus enterotoxin, bacillus cereus, Campylobacter, salmonella, E coli, Norwalk virus

·        Systemic infection: if sicker than history suggests then UTI, Pneumonia, otitis media, meningitis, sepsis (including meningococcaemia)

·        Surgical conditions: Appendicitis, intussusception, bowel obstruction, Hirschsprung‟s enterocolitis, pyloric stenosis, incarcerated inguinal hernia, testicular torsion

·        Other disorders:

o   Diabetic ketoacidosis

o   Antibiotic associated diarrhoea

·        Haemolytic uraemic syndrome (renal failure, haemolytic anaemia and thrombocytopenia, eg due to E Coli verocytotoxin, also drugs, SLE, etc)

·        Poisoning

Warning Signs

·        Seek urgent advice if any of:

o  Vomiting bile or blood

o  Severe abdominal pain 

o  Toxic appearance (ie more than just gastro): lethargy, poor perfusion, hypo/hyper ventilation, cyanosis 

o  Abdominal signs: distension, tenderness, guarding, mass, hepatomegaly

o  Failure to thrive

o  Neonate

Diagnostic Clues

·        Sudden onset of fever, vomiting and watery diarrhoea: viral gastroenteritis

·        Cramping abdominal pain and frequent bloody, mucousy stools: bacterial gastroenteritis. If an infant and severe pain or pallor, consider intussusception

·        Colicky pain, RIF pain, bile stained vomiting and distension ® surgical case

·        Season: Rotavirus during winter epidemics, giardia and cryptosporidia during the spring and campylobacter in the summer

History

·        Vomiting: bile, blood, coffee grounds, volume, frequency, total duration

·        Diarrhoea: nature, colour, consistency, blood, mucus, frequency, volume, total duration

·        Amount and type of recent food and fluid intake

·        Urinary output

·        Other symptoms:

o  Fever

o  Abdominal, groin or scrotal pain

o  Urinary symptoms

o  Respiratory symptoms

o  Recent illness

·        Other:

o  Antibiotics and other drugs

o  Infectious contacts

o  Possible contaminated food ingestion, including shellfish

o  Overseas travel in the last 2 months

o  Immunisation

o  Other medical conditions, GI, diabetes, heart or renal

Management

·        Principles:

o  Dehydration is the most important complication.  In infants it can appear in several hours

o  See Topic: Assessing fluid loss, for assessment of dehydration and rehydration

·        Investigations:

o  Stool microbiology: Only if:

§  Blood in the stool

§  Recent overseas travel

§  Suspected epidemic or food poisoning

§  Child in an institution

§  Chronic diarrhoea (> 3 weeks)

o  Biochemistry: Na, K, Cr +/- glucose +/- ABG if severe, < 3 months, or on IV therapy

o  Other: urines, blood, and CSF culture, CXR, AXR, LFT etc if indicated

·        Management: 

o  Ambulatory if diagnosis not in doubt, family able to cope, have transport, no dehydration and good fluid intake

o   Admission if: diagnosis in doubt, < 3 months, high risk, dehydration, failure to improve, pre- existing condition (get sicker quicker: eg Ileostomy, short gut, cyanotic heart disease, renal failure, diabetes, etc) 

o   IV Rehydration if: shocked, severely dehydrated, failed trial of oral therapy

·        Treatment principles:

o   For a non-dehydrated child: 

§  Small, frequent sips of Gastrolyte (doesn‟t fix diarrhoea) – not for bloody dysentery (dehydration not the biggest concern). 5 – 7 ml/kg/hr

§  ½ strength formula feeds

§  Fruit juice diluted 1:4 

o   Maintain nutrition: Get back to solids within 6 – 12 hours if possible: banana, apple, rice, potato, noodles, toast and vegemite

o   Breast-feeding is continued

o   Do not use anti-emetics nor anti-diarrhoeal agents

o   Dehydrated child

Lactose Intolerance

·        Small bowel injury ® temporary lactose intolerance

·        Most common in bottle feed babies < 6 months.  Uncommon in breast-feed babies.

·        Clues are consistent fluid stools, or their restarting with reintroduction of milk feeds, excess flatus, perianal excoriation

·        Testing: Collect 5 drops of stool from a plastic lined nappy, mix with 10 drops of water and add a Clinitest tablet. Colour reaction of > ¾% indicates sugar is present

·        Change to a lactose free formula for 3 – 4 weeks, then introduce the old feed over 2 – 3 days