Everything about Oral Rehydration Therapy totally explained
Oral rehydration therapy, (also called
ORT,
oral rehydration salts or
solutions (ORS),
oral electrolyte), is a simple, cheap, and effective treatment for
diarrhea-related
dehydration, for example due to
cholera or
rotavirus. It consists of a
solution of
salts and other substances such as
glucose,
sucrose,
citrates or
molasses, which is
administered orally. It is used around the world, but is most important in the
Third World, where it saves millions of children from
diarrhea—still their leading cause of death.
History
Since ancient times, caregivers substituted cholera patient's water loss with
rice water,
coconut juice,
carrot soup etc. Before the practice of ORT was known, modern doctors used
intravenous fluid therapy to compensate for fluid loss in diarrhea.
Physiologists noted in the
1950s that
sodium and glucose were
cotransported along the
gastrointestinal epithelium. Using
histological and other techniques it was shown that the epithelium wasn't disrupted in cholera. These notions provided a physiological basis for the use of ORT in
clinical medicine. ORT was developed in the late
1960s by researchers in
India and
International Centre for Diarrhoeal Disease Research, Bangladesh (then East Pakistan), for the treatment of cholera.
Smaller
clinical trials in the late 1960s (like those of
Hirschhorn,
Nalin,
Pierce etc.) confirmed the efficacy of adding glucose to
sodium chloride solutions for ORT.
The
Indo-Pakistani War of 1971 provoked a public health emergency in the refugee camps set up to house those fleeing the violence. With cholera spreading rapidly and death rates rising, medical teams ran out of intravenous fluids.
Dr. Mahalanabis, the head of a medical centre in one of the camps (accommodating 350,000 refugees) instructed his staff to distribute Oral Rehydration Salts (ORS). In the refugee camps where ORS was being used to treat over 3000 patients, the
death rate was only 3%, compared to 20–30% in those camps using only intravenous fluid therapy. Others replicated these findings and found ORT can be used in babies.
Meanwhile, further studies demonstrated the mechanism by which cholera caused fluid loss,
for example because the
cholera toxin constitutively activates the
enzyme adenylate cyclase in the
cells of the
intestine. Research at the International Centre for Diarrhoeal Disease Research, Bangladesh contributed much to these discoveries.
In
2002, Drs. Norbert Hirschhorn, Dilip Mahalanabis, David R. Nalin, and Nathaniel F. Pierce were awarded the first
Pollin Prize for Pediatric Research, in recognition of their work in developing ORT.
In 1978 the
World Health Organisation launched a worldwide campaign to reduce mortality related to diarrhea, with ORT as one of the principal elements of that program.
Between
1980 and
2000, ORT decreased the number of children under five dying of diarrhea from 4.6 million worldwide to 1.8 million—a 60% reduction. According to
The Lancet (1978), ORT is "potentially the most important medical discovery of the 20th century".
Today, the total production is around 500 million ORS
sachets per year, with the
children's rights agency
UNICEF distributing them to children in around 60
developing countries. ORT represents a cheap and effective way of reducing the millions of deaths caused each year by diarrhea. ORT is part of "GOBI", a low cost program to increase child survival in developing countries, including Growth monitoring, ORT, Breastfeeding, and Immunization. http://www.unicef.org/publications/files/1946-2006_Sixty_Years_for_Children.pdf
Physiology
Oral rehydration therapy is widely considered to be the best method for combating the
dehydration caused by
diarrhea and/or
vomiting.
Various diseases cause damage to the
intestine, allowing water to flow from the blood into the intestine, depleting the body of both fluid and
electrolytes. This may be
In the human body, water is absorbed and secreted passively; it follows the movement of salts, based on a principle called
osmosis. So, in many cases,
diarrhea is caused by intestine cells secreting
salts (primarily sodium) and water following passively along.
Simply drinking water is ineffective for 2 reasons: (1) the large intestine is usually secreting instead of absorbing water, and (2)
electrolyte losses also need compensating. As such, the standard treatment is to restore fluids
intravenously with water and salts. This requires trained personnel and materials which are not sufficiently available in the
Third World.
However, it was discovered that the body can absorb a simple
solution containing both sugar and salt. The dry ingredients can be mixed and packaged, and then the solution can be prepared and delivered by people with minimal training. One diarrhea mechanism (like in
cholera, which is a very dangerous form of profuse diarrhea), is an
enterotoxin interfering with
enterocyte cAMP and
G-proteins. However, water can still be absorbed by cAMP-independent mechanisms, like the
SGLT-transporter (sodium and glucose transporter, of which two types exist). This is achieved by combining
salts and
glucose.
Oral rehydration can be accomplished by drinking frequent small amounts of an oral rehydration salt solution.
It is important to rehydrate with solutions that contain electrolytes, especially
sodium and
potassium, so that
electrolyte disturbances may be avoided. Sugar is absolutely essential to improve adequate absorption of electrolytes and water, but the presence of sugar in ORS solutions does tend to cause
diarrhea to worsen. Although oral rehydration with a sugar solution doesn't stop diarrhea, and the diarrhea contributes to further loss of fluids, oral rehydration helps replace these fluids. It thus keeps the body hydrated and gives the patient a greatly improved chance of surviving the diarrhea. If a broth can be prepared from simple carbohydrates and substituted for sugar in the solution, diarrhea can sometimes be reduced while oral rehydration remains effective.
Often
sodium bicarbonate or
sodium citrate is also added to formulas in an attempt to revert
metabolic acidosis.
Recipe
There are several commercially available products but an inexpensive home-made solution consists of 8 level
teaspoons of
table sugar (sucrose) and 1 level teaspoon of
table salt mixed in 1
liter of water (
Rehydration Project: Home made recipe
). Fructose (fruit sugar) or artificial sweeteners shouldn't be substituted for the table sugar in this recipe. A half cup of
orange juice or half of a mashed
banana can be added to each liter both to add potassium and to improve taste.(
(External Link)) If commercial solutions are used, true rehydration solutions should be used and
sports drinks should be avoided (especially in younger children) as these solutions contain too much sugar and electrolytes.
Technique
Adults and children with dehydration who are not vomiting can be allowed to drink these solutions in addition to their normal diet. People who are vomiting should be fed small frequent amounts of ORS solution until dehydration is resolved. Once they're rehydrated, they may resume eating normal foods when
nausea passes.
Vomiting itself doesn't mean that oral rehydration can't be given. As long as more fluid enters than exits, rehydration will be accomplished. It is only when the volume of fluid and electrolyte loss in vomit and stool exceeds what is taken in that dehydration will continue.
Further Information
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