Gastroenteritis

Conor is a 10 kg, 13-month-old boy who presented to the ED with a 24-hour history of diarrhoea and vomiting.  He has had 5 episodes of non-bloody, non-bilious vomits. Since waking up this morning has had two episodes of loose/watery, non-bloody, malodorous stools. They have not ‘flooded’ the nappy but were quite large. 

He is taking sips of fluid (mixtures of water, milk, and juice are being offered) and has only eaten half a digestive biscuit so far today. He had a fairly large wet nappy last night but not since, though it’s now difficult to tell as his last nappy was dirty. 

He is alert and looking around while being carried but is upset about leaving his mother’s arms. He cries with tears and has a normal heart rate, but his mother is worried about his dry lips. She was told by a healthcare worker neighbour that he would “need a drip.”

CRT, HR, and BP are normal. His temperature is 37.8. His nappy is dry and has been on for 3 hours now. His capillary glucose measurement is 3.2. You decide he’s probably mildly dehydrated.

Gastroenteritis (GE) is the presence of diarrhoea or vomiting (or both) that may or may not be accompanied by fever, abdominal pain and anorexia.  Diarrhoea is the passage of excessively liquid or frequent stools with high water content.  Although often felt to be a common minor illness presentation, it is a major cause of childhood mortality and morbidity, causing millions of deaths worldwide in children in low and middle-income countries; of all child deaths from gastroenteritis, 78% occur in Africa and South-East Asia. 

Gastroenteritis accounts for a huge proportion of GP and ED presentations. In Europe, acute gastroenteritis is the third most common cause of hospital admission, accounting for between 4% and 17% of admissions. In Australia, gastroenteritis caused by rotavirus alone accounts for 115,000 GP visits, 22,000 ED visits, and 10,000 hospital admissions a year, with an estimated cost of 30 million Australian Dollars (£12m, €18m). In the UK, 20% of GP consultations in the under-5s are for GE.

It’s important to differentiate gastroenteritis from more sinister causes of vomiting.  The presence of diarrhoea is reassuring but doesn’t exclude other intra-abdominal causes.  The same can be said for pain out of proportion with gastroenteritis, distension, peritoneal signs or localised tenderness.

Most cases are not associated with complications but when complications do occur, the commonest are electrolyte disturbance and metabolic acidosis.  Supplementary fluids through oral or intravenous routes are the most effective way to avoid these complications.

Gastroenteritis in low—and middle-income countries can present differently, have different aetiologies, be often managed differently, and be a larger burden to healthcare systems in general than in high-income countries. This post will focus on gastroenteritis in high-income countries. Vecchio et al. (2016) is an interesting read for more information about comparisons of guidelines across the world.

This is not meant to provide a clinical practice guideline but rather an overview of the illness.  Many (if not all!) paediatric emergency departments or general paediatric units have their own guidelines.

Pathophysiology of gastroenteritis

Worldwide, the commonest causes are viral pathogens, most commonly rotaviruses and noroviruses.  Viral infections cause damage to the small bowel enterocytes with resultant low-grade fevers and watery diarrhoea – classically without blood.  Rotavirus strains are seasonal and vary within different geographical areas.  The peak age for these infections is between 6 months and 2 years.  Children with poor nutrition are at higher risk of acquiring gastroenteritis and developing dehydration and complications.

Children with bacterial gastroenteritis are more likely to have bloody stool.

Escherichia coli and Shigella dysenteriae can be complicated by haemolytic uraemic syndrome (HUS).  This is an acute onset, microangiopathic haemolytic anaemia, thrombocytopaenia, acute renal impairment and multisystem involvement.  (To confuse things, HUS can present without bloody diarrhoea.)

Pathogens can be generalised into four groups:

How is gastro transmitted?

Pathogens are spread mainly via the faecal-oral route, acquired by ingesting contaminated food or drink.  Water may be contaminated with bacteria, viruses, or protozoa. Undercooked (or inappropriately stored/cooked) meats and seafood are common culprits of bacterial pathogens.  Bacterial contaminants can produce toxins (e.g. Bacillus cereus in re-warmed rice or Staphylococcus aureus in ice cream).

Pathogens causing gastroenteritis can also be transmitted without the patient being symptomatic.

How do you assess a child with gastroenteritis?

Gastroenteritis is a clinical diagnosis.  Enquire about sick/infectious contacts and potential sources (recent travel, food).  Enquire about the frequency of symptoms and intake of fluids.  Note the frequency of urination.  Note other things that may cause diarrhoea, e.g. recent use of enteral antibiotics or chronic constipation with overflow diarrhoea, the presenting feature. 

In the presence of signs such as high fever, long duration of symptoms, severe abdominal pain or bilious vomiting; review the diagnosis and do not immediately label as gastroenteritis.

Treating dehydration

Oral hydration solutions

Most children are not dehydrated and can tolerate oral fluids, so they can be managed at home.  Take a look at Nikki Abela’s DFTB19 talk on top tips for a high-yield dehydration assessment.

When children are only mildly to moderately dehydrated, as a general rule, they can be treated with oral/enteral rehydration with low osmolality oral rehydration solution (ORS).  Worldwide, ORS is recognised as first-line therapy. The WHO, European Society for Paediatric Gastroenterology and the American Academy of Paediatrics support treating mild to moderate dehydration with enteral rehydration. The WHO recommends a low osmolality (hypo-osmolar) solution, usually containing sodium, potassium, chloride, carbohydrate (glucose) and a base.  Low osmolarity solutions reduce the need for IV fluids, reduce stool output and reduce vomiting frequency.

But… a major limitation to using ORS is its taste – and this is where apple juice comes in. For minimally dehydrated patients, half-strength apple juice is associated with fewer treatment failures than ORS and could be a more palatable alternative.  Take a look at a sweet summary (pun intended!) of the “apple juice trial”.

Breastfeeding should continue, and a child can be supplemented with ORS if necessary. After the illness has passed, children can return to a normal diet.

Enteral (oral / NG) versus IV hydration

Most studies show that enteral rehydration with ORS is just as effective as IV hydration in mild to moderate dehydration. A 2006 Cochrane analysis concluded that enteral rehydration is as effective, if not better than IV rehydration, with fewer adverse events and a shorter hospital stay. It is also less invasive (even with NG placement); anecdotally, parents’ satisfaction is greater. It is very safe.

Enteral rehydration only fails in approximately 1 in 20-25 children.

Barriers to oral rehydration include unfamiliarity with the benefits, the misconception that it takes longer than IV therapy and that it has a high failure rate.

Contraindications to enteral rehydration include haemodynamic instability, abdominal distension, concern over ileus, absent bowel sounds, or impaired airway reflexes.

IV therapy is more invasive and involves placing and maintaining IV access.  There are also iatrogenic complications, including electrolyte disturbance, should inappropriate fluids/composition/volume / rate be used. 

But… in severely dehydrated children, put away the ORS and apple juice. They will need IV rehydration as the first line.

Antiemetics

How can we support enteral fluids? Well, children who receive Ondansetron are less likely to vomit, have greater oral intake and are less likely to require IV hydration.  A Cochrane review demonstrates that Ondansetron also increases the proportion of children who stop vomiting when compared to placebo [RR1.4] and reduces the proportion of children needing IV therapy (and therefore admission rate) [RR 0.41].  Median length of stay is also shorter in the ED. 

Reported side effects are rare, with very few reported side effects other than a few cases of increased frequency of diarrhoea.

Antiemetics alleviate vomiting by acting on the ChemoReceptor Trigger Zone and vomiting centre.  Ondansetron is a 5HT3 receptor antagonist.  This class of antiemetics have fewer adverse effects (than dopamine antagonists, anticholinergics, antihistamines and corticosteroids) and can be safely used in children.  The NICE guideline discusses its off-licence use (at the time of publication, its licence was for post-operative nausea and vomiting and chemotherapy-induced vomiting).

Ondansetron prolongs the QT interval.  Recommendations are it should be avoided in those with long QT and should be used with caution where there may be electrolyte imbalance (severe dehydration) or on other QT-prolonging medication.

Ondansetron is relatively cheap  £1.71 for 10 4mg tablets) and is available in oro-dispersible form (though these are much more expensive, at £36 for 10x4mg tablets) and liquid (£36.82 for a 40mg [50ml] bottle).

Do probiotics help in the management of gastroenteritis?

An ESPGHAN working group position paper on the use of probiotics in acute paediatric gastroenteritis concludes that:

• Effects seen in clinical trials are probiotic strain specific (this makes ‘trial-life’ difficult to replicate in ‘real-life’).
• A lack of evidence now doesn’t mean that there won’t be evidence sometime in the future. 
• The safety profile of certain strains cannot be extrapolated to other strains.
• Studies that report benefits in certain doses in certain settings have insufficient evidence to support a health benefit at lower doses and different setting.

…the jury’s still out.

Other therapies

Antibiotics and anti-diarrhoeal agents aren’t routinely recommended in managing paediatric gastroenteritis.

For gastroenteritis in high-income countries, the WHO does not recommend adding zinc to a treatment regimen (it is for gastroenteritis in low and middle-income countries). 

What tests do you need to do for a child with gastro?

Routine lab testing in mild and moderate gastroenteritis is useless in these patients and should be avoided unless clinically indicated.

This goes for stool samples, too.  Stool cultures are not routinely indicated in immunocompetent children with non-bloody diarrhoea.

Confirmation of viral gastroenteritis after the child has been discharged from the ED and is likely on the road to recovery at home adds very little to (A) the clinical diagnosis of viral gastroenteritis in the ED, (B) the management plan, and (C) the clinical outcome. 

Should the investigation influence management, then stool sampling may be helpful.  This could be applicable where an outbreak may be suspected in school or creche, where there may be a public health benefit.

Stool samples should be sent in cases of bloody diarrhoea, immunodeficiency and recent foreign travel.

How about tests for dehydration? Sadly, no one test correlates clinically with dehydration. Urine specific gravity in infants is unreliable because the kidney reaches adult concentration abilities after the age of 1. Also, the child often doesn’t begin urinating until rehydration has begun.

And glucose? Well, almost 10% of GE patients aged 1 month to 5 years in high-income countries present with hypoglycaemia. Risk factors for hypoglycaemia on presentation include a longer duration and increased frequency of vomiting. It would be reasonable to consider point-of-care glucose testing at triage for young children as identifying hypoglycaemia on clinical grounds alone is difficult in this age group. 

Preventing gastro

The key to reducing the burden (and generally for an all-round happier life!) is preventing acute gastroenteritis.  Rotavirus vaccination is now commonplace in the Antipodes, the UK and Ireland. It is very effective.

In the home and in the ED…Handwashing, handwashing, handwashing!

Vaccination leads to a profound reduction in presentations and admissions and a fall in overall seasonal workload, often within the first year after universal vaccination against rotavirus is introduced.  Even though only those under 1 year old are generally vaccinated, it has been shown to contribute to a significant herd effect, with fewer cases than expected in older children.

In Scotland, where initial vaccine uptake was 93- 94% during the first 2 years, annual rotavirus-confirmed gastroenteritis cases fell by 84.7%, and bed days reduced by 91% (from 325 to just 29), without any documented cases of intussusception.  Reductions were seen across all age groups despite only infants receiving the vaccine.  Similar results can be seen in other areas of the UK and Ireland.

What not to miss

Do not assume isolated vomiting in a child is gastroenteritis. Consider other causes—these vary widely, from inborn errors of metabolism to diabetes mellitus, surgical obstruction, and urinary tract infections. If you’d like to hear more, check out Dani’s talk on vomiting in children in DFTB Essentials.

Beware chronic diarrhoea in an infant – do they have malabsorption or is this a presentation of IBD or an immunodeficiency?

Beware the non-thriving child with diarrhoea.

And beware of chronic diarrhoea.

But what happened to Conor?

References

BK F, A H, JC C. Enteral vs Intravenous regydration therapy for children with gastroenteritis: A meta-analysis of randomized controlled trials. Arch Paediatr Adolesc. 2004;158(1):483–90.

Colletti JE, Brown KM, Sharieff GQ, Barata IA, Ishimine P. The Management of Children with Gastroenteritis and Dehydration in the Emergency Department. J Emerg Med [Internet]. 2010;38(5):686–98. Available from: https://dx.doi.org/10.1016/j.jemermed.2008.06.015

Elliott EJ. Acute gastroenteritis in children. Br Med J. 2007;334(7583):35–40.

Fedorowicz Z, Jagannath V, Carter B. Antiemetics for reducing vomiting related to acute gastroenteritis in children and adolescents. [Internet]. Cochrane database of systematic reviews. 2011. Available from: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD005506.pub5/full

Freedman SB, Willan AR, Boutis K, Schuh S. Effect of dilute apple juice and preferred fluids vs electrolyte maintenance solution on treatment failure among children with mild gastroenteritis: A randomized clinical trial. JAMA – J Am Med Assoc. 2016;315(18):1966–74.

Forrest R, Jones L, Willocks L, Hardie A, Templeton K. Impact of the introduction of rotavirus vaccination on paediatric hospital admissions , Lothian , Scotland : a retrospective observational study. 2017;323–7.

Hartling L, Bellemare S, Wiebe N, Kf R, Tp K, Wr C, et al. Oral versus intravenous rehydration for treating dehydration due to gastroenteritis in children (Review). 2006;

MARLOW RD, MUIR P, VIPOND I, TROTTER CL FA. Assessing the impacts from the first year of rotavirus vaccination in the UK. Arch Dis Child. 2015;100(Supl 3):A30.

NICE. Management of vomiting omiting in children and y young oung people with gastroenteritis : ondansetron. NICE GUIDELINES. 2014. p. 1–20.

Szajewska H, Guarino A, Hojsak I, Indrio F, Kolacek S, Shamir R, et al. Use of Probiotics for Management of Acute Gastroenteritis : A Position Paper by the ESPGHAN Working Group for Probiotics and Prebiotics. 2014;58(4):531–9.

Vecchio A Lo, Dias A, Berkley JA, Boey C, Cohen MB, Cruchet S, et al. Comparison of Recommendations in Clinical Practice Guidelines for Acute Gastroenteritis in Children. Gastroenterology. 2016;63(2):226–35.