Oral rehydration therapy

Oral rehydration therapy, (also called ORT, oral rehydration salts or solutions (ORS), oral electrolyte), is a simple, cheap, and effective treatment for dehydration associated with diarrhea, particularly gastroenteritis, such as that caused by cholera or rotavirus. ORT consists of a solution of salts and sugars which is administered orally. It is used around the world, but is most important in the developing world, where it saves millions of children from death due to diarrhea—the second leading cause of death in children under five.^[1]

History

Presciptions from the ancient physician Sushruta date back over 2500 years with treatment of acute diarrhea with rice water, coconut juice, and carrot soup. However, this knowledge did not carry over to the Western world, as dehydration was found to be the major cause of death secondary to the 1829 cholera pandemic in Russia and Western Europe. In 1831, William O'Shaughnessy noted the loss of water and salt in the stool of cholera patients and prescribed intravenous fluid therapy to compensate. The results were remarkable, as patients who were on the brink of death from dehydration recovered. The mortality rate of cholera dropped from 70% to 40% with the use of hypertonic IV solutions.^[2]

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 3,000 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, i.e. 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.^[3] In May of 2001, the International Centre for Diarrhoeal Disease Research, Bangladesh received the first Gates Award for Global Health in recognition of its role in developing Oral Rehydration Solution. In 2007, three former ICDDR,B scientists, Dr. Richard Alan Cash, Dr. Dilip Mahalanabis and Dr. David R. Nalin, were also individually honoured for their efforts in testing and implementing ORS, sharing the 2006 Prince Mahidol Award for public health, which is presented annually for outstanding contributions in public health and medicine. In addition to the award for public health, a separate award for medicine was also presented to Professor Stanley George Schultz in recognition of his research on sodium absorption, which provided an important basis for the discovery of ORS.

In 1978 the World Health Organization 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". Despite the success and effectiveness of ORT, uptake of ORT has slowed, which may result in a decline in the progress on mortality rates from diarrheal disease unless swift action is taken to increase uptake of ORT.^[4]

Today, the world production of ORS sachets is around 500 million sachets per year. The children's rights agency UNICEF distributes them to families with 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.^[5]

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^{citation needed} 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 does not 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.

Recently, the ORS formulation was revised to reduce the sodium and glucose contents. This new, low-osmolarity ORS, improves the efficacy of ORS, reduces the need for unscheduled intravenous infusions, lowers stool volume, and causes less vomiting compared with standard ORS.^[6] While the old formulation of ORS is still acceptable, the World Health Organization and UNICEF are now actively promoting this new formulation.

UNICEF/WHO definition

UNICEF and the WHO jointly maintain the official guidelines^[7] for the contents of reduced osmolarity ORS packets. These guidelines are used by manufacturers of commercial ORT packets that are available for purchase and were last updated in 2006.^[8]

Additionally, there is an additional recommendation of zinc supplementation^[7] for the management of diarrheal disease in addition to ORT, particularly for pediatric patients. Preparations are available as a zinc sulfate solution for adults,^[10] a modified version for children,^[11] and also a tablet form for children.^[12]

Although magnesium is a common ingredient in commercial electrolyte solutions, it is not part of the UNICEF/WHO guidelines for ORT. Severe diarrhea causes an isotonic loss of fluid from the body's extracellular compartment. Because very little magnesium is in this compartment, very little is lost in diarrhea and there is no need to replace it.^{citation needed}

Recipes

There are several commercially available products^[13]^[14] 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 should not 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.([1]) This recipie is preferable to sports drinks which are formulated to rehydrate healthy individuals and so contain too much sugar and too little electrolytes for this purpose.^[15]

The online Merck Manual lists a recipe of "1 L of water to 3.5 g NaCl [salt], 2.9 g trisodium citrate (or 2.5 g NaHCO3 [Baking soda]), 1.5 g KCL [Salt substitute, Potassium chloride], and 20 g glucose"^[16].

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 are rehydrated, they may resume eating normal foods when nausea passes.

Vomiting itself does not mean that oral rehydration cannot 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.

Contents

History

Physiology

UNICEF/WHO definition

Recipes

Technique

See also

References

History

Footnotes

External links