Gastroenteritis is a common form of diarrhoea that predominantly attacks children. It is endemic in developing countries, but seasonal epidemics occur. Attempts to find a specific organism as a cause are often unsuccessful and not essential, as management and control are the same. Strains of enterotoxigenic, enteropathogenic and enteroag-gregative Escherichia coli as well as enteric viruses, particularly rotavirus, are the main organisms. Campylobacter (Section 9.2) is now a major cause.
Clinical features Profuse, watery diarrhoea with occasional vomiting, but despite the fluid nature of the stools, faecal material is always present. There is never the rice-water stool characteristic of cholera. Water and electrolytes are lost, which in the young child may be sufficient to cause dehydration and ionic imbalance, leading to death. Normally, a self-limiting condition, but in unhygienic surroundings, or where babies' bottles are used, repeated infections occur leading to chronic loss of nutrients and subsequent malnutrition. A serious infection in neonates, mortality decreases with age until in adults, it is just a passing inconvenience (travellers' diarrhoea).
Diagnosis is made on clinical criteria unless laboratory facilities sufficient to identify viral infections are available. Specific DNA probes are likely to be the most appropriate method of identifying causative organisms in developing countries if they can be made cheap enough.
Transmission Epidemics occur in families or groups of children sharing similar surroundings. Infection is often seasonal, for example, the beginning of the rains heralding an outbreak. This would suggest transmission by water and simple control measures, such as boiling of water, can
Table 8.1. Diarrhoeas.
Acute watery diarrhoea
Salmonellosis, food poisoning
(viral) Cryptosporidiosis Cholera
Acute diarrhoea with Bacillary dysentery, blood Campylobacter
Salmonella, Staphylococci, B. cereus, C. perfringens, V. parahaemolyticus E. coli or non-specific
Rotavirus and other enteroviruses Cryptosporidium V. cholerae
Shigella sp., C. jejuni
Chronic diarrhoea Giardiasis G. intestinalis
(Sprue or malabsorption syndromes)
Chronic diarrhoea Amoebiasis E. histolytica with blood
Balantidiasis B. coli
Schistosomiasis S. mansoni
Sudden onset with vomiting in group of people associated by food
Common, mainly in children, epidemic
Occurs in children, often in institutions (hospitals, schools, etc.)
Severe, dehydration, rice-water stools, epidemic
Severe, seasonal, all ages
Sporadic, from contaminated food, animal reservoir
Mainly children and travellers
Adults, mostly males; nutritional deficiencies especially of folic acid
Cooler climates, mainly adults
Similar to amoebiasis; associated with pigs
Endemic areas, characteristic eggs in stools
B. (cereus), Bacillus; C. (perfringens), Clostridium; V. (parahaemolyticus), V. (cholerae) Vibrio; E. (coli), Escherichia;
C. (jejuni), Campylobacter; G. (lamblia), Giardia; E. (histolytica), Entamoeba; B. (coli), Balantidium; S. (mansoni), Schistosoma. Many other diseases cause diarrhoea (e.g. measles, malaria, tonsillitis).
stop the epidemic. Improperly sterilized babies' bottles or their contents are a common method of infecting the neonate.
Incubation period 12-72 h (generally 48 h).
Occurrence and distribution Gastroenteritis is found throughout the world, especially in developing countries and in conditions of poor hygiene. It is particularly common where bottle-feeding has been recently introduced, such as by unscrupulous infant-feed companies. A seasonal distribution suggests contamination of the water supply.
Control and prevention is by the following methods:
• promotion of breast-feeding;
• use of oral rehydration solution (ORS) in the community;
• improvement in water supply and sanitation;
• promoting personal and domestic hygiene;
• vaccination (rotavirus and other vaccines, e.g. measles).
Breast-feeding not only provides a sterile milk formula in the correct proportions (in contrast to the often-contaminated bottle), but also promotes lactobacilli and contains lactoferrins and lysozymes. Promoting breast-feeding and the administration of
ORS solution in the community are the main control strategies. Improvement in water supplies and sanitation, with the promotion of personal hygiene, are long-term measures.
The oral cholera vaccine WC/rBS has been shown to be about 60% effective against enterotoxigenic E. coli so might have some place in control although its protective effect in infants is considerably less. Rotavirus vaccine (RRV-TV) has so far been shown to be less effective in developing countries than the developed and several cases of intussusception has resulted in its withdrawal from use in the latter. Preventing other childhood infections by vaccination, especially those associated with gastro-intestinal disease, such as polio and measles, can reduce the severity of gastroenteritis.
Treatment is by replacement of fluid and electrolytes using ORS in the moderately dehydrated and intravenous replacement in the severely dehydrated.
A suitable ORS is made by dissolving the following constituents in 11 of water:
3.5 g (Na+ 90 mmol)
2.9 g (citrate 10 mmol)
1.5g (K+ 20 mmol, Cl"
20.0 g (glucose 111 mmol)
These ingredients can be obtained separately or in packets of readily prepared mixtures. In the absence of prepared packets, a simpler formulation can be made as shown in Fig. 8.1, which consists of mixing salt and sugar in 1 l of clean water. Potassium is not an essential constituent, but addition of the juice of one orange is useful. Tea leaves also contain potassium, so the mixture can be prepared as tea with the addition of salt and sugar. Teaspoons vary in size and it is dangerous to give too much salt; hence a useful check is for the mother to taste the solution before adminis-
One litre clean water
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