Diarrhoea and Vomiting (D&V) - Some Common Causative Agents and Their Management (Part 2)

Diarrhoea and Vomiting (D&V) - Some Common Causative Agents and Their Management (Part 2)

Travellers Diarrhoea (TD):

This is classically defined as passage of three or more unformed stools within a 24 hour period during or shortly after a period of foreign travel.

It is frequently encountered by individuals travelling to developing countries although no country is exempt in our modern day 'jet age'.

Aetiology:

Most common cause of TD is the ingestion of faecally contaminated food or water.

A number of viral, parasitic and bacterial organisms can cause TD. Among the common enteroviruses which have been implicated include: Coxsackie, Polio and echoviruses while the common parasites include Entamoeba histolytica (Amoebiasis/Amoebic dysentery) and Giardia lamblia (Giardiasis) but the majority of cases are associated with bacteria, particularly the pathogen enterotoxigenic Escherichia coli (ETEC).

Here is a list of the most common causes of TD:

(1)  Enterotoxigenic E.coli

(2)  Shigellosis spp. (bacillary dysentery)

(3)  Aeromonas spp.

(4)  Salmonella spp.(Already discussed in Part 1)

(5)  Non-Cholera Vibrio spp.

(6)  Camphylobacter  jejuni

(7)  Pleisonias Shigelloides

Pathogenesis:

The bacterial organisms produce either a heat-labile or a heat-stable enterotoxin, causing marked secretory diarrhea and vomiting after 1- 2 days incubation.

Treatment:

(a) If diarrhea is associated with severe dehydration, intravenous fluid and electrolyte replacement is indicated.

This is of particular importance in the case of diarrhea associated with Vibrio.

(b)Antibiotics: These can be used to limit the duration of symptoms and prophylaxis may help to prevent the disease.

(c) In most cases the illness is usually mild and self-limiting after 3 - 4days. Most important supportive treatment is fluid and electrolyte replacement; either orally (if there is no vomiting) or intravenously if there is.

Campylobacter jejuni:

Aetiology and Pathogenesis:

This infection is basically a zoonosis (a disease of animals that may secondarily be transmitted to man). The organism inhabits the gut of cattle and poultry, the commonest source of infection being chicken or contaminated milk.

There is also an association with pet puppies.

Campylobacter infection is now the most common cause of bacterial gastroenteritis in the U.K., even though most of the cases are sporadic.

The incubation period is 2-5days.

Clinical Features & Treatment:

Severe colicky abdominal pain which mimics surgical pathology at times ensues and is followed by nausea, vomiting and quite significant diarrhoea which may become blood stained as the illness progresses.

Majority of Campylobacter infections affect fit, young adults and are self-limiting after 4-7 days.

10-20% will have prolonged symptomatology warranting treatment with antibiotics such as ciprofloxacin or a macrolide, while another 1% of cases will develop bacteraemia and distant foci of infection.

Non-infectious Diarrhoea:

Among the common causative agents of non-infectious diarrhoea the following should be considered:

-      Drugs:These include purgatives (most common); antibiotics, and digoxin (rare).

-      Others:

Diverticulitis:- This occurs commonly.

Diabetes, thyrotoxicosis (rare)

Spastic colon / Nervous diarrhoea (common)

Malabsorption syndromes - especially following vagotomy (an operation to divide the Vagus nerve around the stomach area)

Ulcerative colitis and Crohn's disease.

Colonic carcinoma - at times manifests with spurious diarrhoea secondary to partial obstruction.