Diarrhoea and Vomiting (D&V) - Some Common Causative Agents and Their Management (Part 3)

Antibiotic Associated Diarrhoea (Clostridium difficile Infection):

A history of any antibiotic therapy in the 6weeks prior to the onset of diarrhoea can be related to the finding of Clostridium difficile or its toxins in the stool.

This is a potent cause of diarrhoea and can produce life threatening pseudomembranous colitis.

This diagnosis is common in the elderly and treated often with metronidazole (Flagyl) for 10days.

Vancomycin may be used where the organism is unresponsive to metronidazole.

Cholera:

Aetiology & Epidemiology:

Cholera is caused by Vibrio cholera, a bacterium. Serotype 01 causes acute watery diarrhoea plus vomiting.

Following its origin in the Gangs valley, devastating epidemics have occurred, especially during large religious festivals.

Pandemics have spread worldwide.

The 7th pandemic due to the El Tor biotype began in 1961 and spread via the Middle East to become endemic in Africa.

In 1990 it surfaced in Peru and spread throughout South and Central America.

Since August 2000, there has been a massive outbreak in South Africa.

The El Tor biotype is more resistant than the classical vibrio and can cause prolonged carriage in about 5% of infections.

A new classical toxigenic strain, serotype 0139, established itself in Bangladesh in 1992 and started a new pandemic.

Mode of Infection/Transmission:

The infection spreads via the stools and vomitus of symptomatic individuals or through the much larger number of subclinical cases (asymptomatic carriers).

Transmission is through infected drinking water, foods contaminated by flies or through the hands of carriers.

The vibrio microorganism survives for up to 2weeks in fresh water and 8weeks in salt water.

Signs and Symptoms (Clinical Features):

Severe diarrhoea starts all of a sudden without abdominal pain or colic and is soon followed by torrential vomiting.

After evacuation of normal gut faecal contents typical "rice water" stools follow, consisting of clear fluid with flecks of mucous.

Classical cholera produces enormous loss of body fluids and electrolytes leading to intense dehydration with muscular cramps. Shock and oliguria develop but mental alertness remains.

Death from acute circulatory failure may occur rapidly unless fluids and electrolytes are replaced quickly. This is why the disease is more dangerous in children.

Improvement however is rapid with proper treatment.

It is to be noted however, that majority of infections cause mild illness, with slight diarrhoea and vomiting.

Occasionally, a very intense illness "cholera sicca" occurs, with massive loss of fluids into dilated bowel, killing the patient before typical gastrointestinal symptoms appear.

Diagnosis:

Clinical diagnosis is easy during an epidemic.

At other times, diagnosis is confirmed bacteriologically from rectal or stool swab cultures.

*Cholera is a notifiable disease under international health regulations.

Treatment/Management:

Quick, early restoration of the circulation by replacement of water and electrolytes is very important and is the key to survival.

Early intervention improves the prognosis.

Oral rehydration solution (ORS) is effective and safe where vomiting has been controlled by initial intravenous fluid therapy.

The addition of resistant starch to ORS reduces faecal fluid loss and shortens the duration of diarrhoea in adolescents and adults.

Total fluid requirements may exceed 50litres over a period of 2-5days. Ringer lactate is the best fluid for intravenous replacement.

Careful attention to fluid balance is especially important in children and they are prone to low blood sugar (hypoglycaemia) during the illness.

3-5days treatment with Tetracycline, or Doxycycline or Ciprofloxacin in adults and children helps to reduce the duration of excretion of vibrio and the total volume of fluids needed for replacement.

*Children should not be given Tetracycline because of discolouration of their dentition.

Prevention:

• Strict personal hygiene


• Clean drinking water (pipe borne or boiled)


• Proper food hygiene to deny flies access.


• Parental and oral vaccines provide limited protection (6months at most)


• In epidemics, mass single dose vaccination and treatment with Tetracycline are valuable.


• Public education, control of water sources and population movement are very important.


• Disinfection of discharges and soiled clothing.

Meticulous hand washing by medical personnel reduces danger of spread.