Paediatrics: Gastrointestinal infections

Gastrointestinal infections

GI infections are the second commonest cause of primary care consultation after the common cold. These infections also cause over 3 million children deaths per year (mostly in developing world).

Viral gastroenteritis

Transmission is by the faecal–oral route, including contaminated water. Epidemics are frequent and usually occur during winter. Breastfeeding is protective. Severity is increased in malnourished children.

Causes

•   Rotavirus (most common).

•   Small round structural virus, e.g. winter vomiting disease caused by ‘Norwalk agent’.

•   Enteric adenovirus.

•   Astrovirus.

•   CMV (in immune-comprised patients).

Presentation

•   Watery diarrhoea (rarely bloody).

•   Vomiting.

•   Cramping abdominal pain.

•   Fever.

•   Dehydration.

•   Electrolyte disturbance.

•   Upper respiratory tract signs common with rotavirus.

•   Vomiting predominates with Norwalk virus.

Investigation 

Is rarely necessary. Stool electron micros-copy or immunoassay can sometimes be useful.

Treatment

Give supportive rehydration orally or with a nasogastric tube, or IV glu-cose and electrolyte solution. Hospitalization is rarely needed (e.g. 10% dehydration, or unable to tolerate oral fluids).

Prognosis

Symptoms generally last <7 days, except in enteric adenovirus, when diar-rhoea frequently goes on beyond 14 days. The child may develop tempo-rary secondary lactose intolerance.

Prevention 

Rotavirus immunization is now available and effective.

Bacterial gastroenteritis

Causes secretory and inflammatory diarrhoea. It is most common under 2yrs of age. Commonest causative organisms include:

• Salmonella spp.;

• Campylobacter jejuni;

• Shigella spp.;

• Yersinia enterocolitica;

• Escherichia coli;

• Clostridium difficile;

• Bacillus cereus;

• Vibrio cholerae.

Sources of infection include 

contaminated water, poor food hygiene (meat, fresh produce, chicken, eggs, previously cooked rice), faecal–oral route.

Presentation

As for viral gastroenteritis plus:

• malaise;

• dysentery (bloody and mucous diarrhoea);

• abdominal pain may mimic appendicitis or IBD;

• tenesmus.

Complications

·Bacteraemia.

• Secondary infections (particularly Salmonella, Campylobacter), e.g. pneumonia, osteomyelitis, meningitis.

• Reiter’s syndrome (Shigella, Campylobacter).

• Haemolytic–uraemic syndrome (E. coli 0157, Shigella).

• Guillain–Barré syndrome (Campylobacter).

• Reactive arthropathy (Yersinia).

• Haemorrhagic colitis.

Investigation

• Stool +/– blood culture (some organisms need specific culture medium).

• Stool Clostridium difficile toxin.

• Sigmoidoscopy if inflammatory bowel disease or colitis.

Treatment

• Rehydration as for viral gastroenteritis.

• Antibiotics are not indicated, as the duration of symptoms is not altered and may increase chronic carrier status, unless there is high risk of disseminated disease, presence of artificial implants (e.g. V-P shunt), severe colitis, severe systemic illness, age <6mths, enteric fever, cholera or E. coli 0157. Most organisms are sensitive to ampicillin, co-trimoxazole, or third generation cephalosporins.

·Consider:

•   erythromycin if Campylobacter;

•   oral vancomycin or metronidazole if Clostridium difficile (causes pseudomembranous colitis).