|Oral Rehydration Therapy and the Control of Diarrheal Diseases (Peace Corps, 1985, 566 pages)|
|Module Two: Diarrhea, dehydration and rehydration|
|Session 5 - Rehydration therapy|
Effective treatment of dehydration requires the replenishment of salts, fluids, and nutrients to the body. Rehydration is necessary for all types of diarrhea. In Session 4 participants learned the signs and symptoms of diarrhea and dehydration that indicate the use of WHO Treatment Plan A (sugar and salt) to prevent dehydration, Plan B (ORS) to treat dehydration, and Plan C (IV or nasogastric tube) for severe dehydration and rapid Rehydration needs. In this session they develop a further understanding of the biological need for rehydration and the reasons for the effectiveness of ORS. Through hands on experience preparing solutions, participants explore the differences in ORT solutions. They also discuss the problems in preparing and giving ORT in the village.
· To explain why oral rehydration is necessary for the prevention and/or treatment of moderate dehydration.
· To accurately 01x two kinds of oral rehydration solutions.
(Steps 2, 3)
· To describe the components of two kinds of oral rehydration solutions and the appropriate use of each solution.
(Steps 1, 4)
· To describe problems in preparing and giving ORT in the village.
(Steps 5, 6)
"Oral rehydration Therapy for Childhood Diarrhea, "Population Reports, The Treatment of Diarrhea (WHO Supervisory Skills).
- 5A ORT Preparation Worksheet
- 5A Materials and Equipment Needed for ORT Stations
- 5B Using Models to Show Why rehydration is important
- 5C Suggestions for a Lecturette on the Hows and Whys of ORS
- 5D Oral rehydration Therapy: The Scientific and Technical Basis
- 5E Storing and Maintaining Supplies of Oral rehydration Salts
- 5F Oral rehydration With Dirty Water?
- 5G A Pinch of Salt, A Handful of Molasses
- 5H Cautious Prescription
Newsprint, markers, Read Trainer Attachment 5A for list of materials and equipment needed for practice stations. Read Trainer Attachment 5B for materials needed for using models.
In strict adherence to WHO guidelines, Peace Corps advocates the use of only two types of ORS solutions-prepackaged and sugar-salt solutions- in Peace Corps projects and in this training program. As discussed in Session 4 and reviewed in this session, WHO Treatment Plans A and B outline the appropriate and effective use of these two solutions in ORT. Before this session, find out what recipes for oral rehydration solutions the government and bother agencies are busing. In some areas more than one agency may be encouraging the use of ORT with different recipes. Be prepared to discuss these differences and their potential for confusing the public.
Please note that research is currently being conducted on "rice powder" ORS. Rice-powder ORS substitutes rice powder (i.e., ground rice) for glucose, an essential component of the standard OR formula (Rice-powder ORS should not be confused with rice water. Rice water is the fluid drained from the rice after cooking. Since it generally contains very little salt and variable amounts of rice starch, rice water is considered unsuitable for active rehydration. It is not an oral rehydration solution.) Possible advantages & disadvantages of rice powder ORS are being studied but no conclusions can be drawn until further research is done.
Trainers should only emphasize rice powder ORS in countries where a definite policy and guidelines on this subject have been developed and operationalized by the MOH. Only in countries where definite policies exist should rice powder ORS be incorporated as an ORT approach. In such cases, the trainer has the responsibility of becoming familiar with exact MOH guidelines and explaining those to the participants through discussion and a handout.
The main purpose of this session is to provide actual experience in correctly preparing the two kinds of solutions. Be sure to allow ample time for practice.
This session requires considerable preparation. Recruit the help of several participants to set up the work stations (with the materials, equipment and task descriptions explained in Trainer Attachment 5A), prepare for the demonstration, and clean up afterwards.
Identify individuals in the group or training center who have had experience preparing and using ORT to act as resource persons during Step 3.
If possible invite a local health worker to participate and assist in this activity. He or she may be able to help you arrange to give the solutions mixed during the session to children in the community or clinic during Step 7.
Ask participants to bring commonly used utenslis from their community work site. Each solution must be mixed as accurately as possible. Predetermine the quantities and weights measured by locally available utensils so recipe mixing may be done precisely under local conditions. Use these utensils in your demonstrations. (See Oral rehydration Therapies for Childhood Diarrhea in the ORT resource packet.)
Ask a participant to help you prepare the demonstration described in Trainer Attachment 5B (Using Models to Explain Why rehydration is important) and the lecturette described in Trainer Attachment 5C (Suggestions for a Lecturette on the Hows and Whys of ORS.)
If available, get copies of the WHO Treatment Chart in the local
language. hive prepare a list of ORT terms in the local language with the
assistance of Peace Corps language trainers.
Step 1 (20 min)
Demonstration and Discussion of Why Rehydration la important
Introduce this Session using the plastic bag, the gourd baby and the watered and wilted flowers to illustrate the need to rehydrate a child with diarrhea (as suggested in Trainer Attachment 5B).
Ask participants to describe Treatment Plan A on the WHO chart, which they discussed in Session 4 (Dehydration Assessment) and explain what this demonstration tells then about Plan A.
Briefly discuss the fluids available in village hoses that are already used or could be used during diarrhea to prevent dehydration (Including sugar salt solution). Also discuss any cultural beliefs that night help or hinder teaching mothers to give children liquids during diarrhea.
The main point of this activity is to illustrate why rehydration is necessary during diarrhea in a clear simple way that can be used by participants with mothers in the village.
It also provides a way to reinforce and use their learning about Treatment Plan A in the WHO Chart. They should recognize that the plastic bog and other models provide an explanation of why plan
Is very important. Emphasize prevention of dehydration as a major
goal for their health education efforts in ORT. Refer back to the circle of
pictures that you made for the diarrhea story in Session 3 (Prevention and
Control of Diarrhea Note that oral rehydration is one important intervention in
Step 2 (15 min)
Lecturette on the Hows and Whys of ORS
Point to the pictures showing the signs of dehydration that were introduced in Session 4. Ask someone to quickly summarize the signs of dehydration. Explain that these physical signs are caused by the loss of sodium, potassium and nutrients during diarrhea, in addition to the loss of water.
Present the lecturette that you prepared using Trainer Attachment SC (Suggestions for a Lecturette on the Hows and Whys of ORS). If possible use a simple diagram to illustrate the way that the body chemistry balance is affected by diarrhea.
Ask someone to describe Treatment Plan B on the HO chart. Discuss the ingredients in ORS and how they help the body regain its chemical balance. Ask someone to explain in their own words when they would give ORS to a child with diarrhea and what the ORS does for the child in comparison to sugar salt solution.
Briefly discuss how people in the village have responded to ORS packets (or are likely to respond it they have not been introduced to them). Build on the discussion of cultural beliefs regarding the acceptability of liquids (from Step 1).
Close this step by telling the participants that they will be spending the rest of the session preparing two different oral rehydration solutions' the kind that should be used at the first sign of diarrhea to prevent dehydration (sugar-salt) and the type used to treat mild dehydration (ORS).
Prepare two sheets of newsprint with the recipes for ORS and for sugar-salt solution as stated in The Treatment of Diarrhea, pages 17 and 42.
During the group's discussion of these two recipes, make sure that the following points are covered:
- Potassium is an essential element in the body and is lost during diarrhea. A minimum level of potassium is needed for the body to function.
For more technical background see Trainer Attachment 5D (Oral
Rehydration Therapy: The Scientific and Technical Basis).
Step 3 (20 min.)
Preparing to Mix Oral Rehydration Solutions
Demonstrate how to mix the two kinds of oral rehydration solution. Have one or two people do return demonstrations and have the group critique their demonstration. Pass the solution around so that everyone has a chance to taste it.
Explain that everyone will be working in small groups at oral rehydration stations for the next hour. Each group will carry out the following tasks at each station:
- Read the instructions for preparing the solution at the station and take turns in mixing and tasting that particular solution.
- Discuss and complete Handout 5A (The ORT Preparation Worksheet) prior to moving to the next station.
- Clean up the station before moving on to the next one.
In doing the demonstration, make sure that you'
- Emphasize washing hands before you begin mixing the solutions.
An alternative approach is to do a correct demonstration then tell
participants that you will be doing an incorrect demonstration and you want thee
to tell you what you did wrong. This repetition helps them learn and remember
the steps in mixing the solutions.
Step 4 (60 min)
Preparing Oral rehydration Solutions
Ask the group to fore small groups, move to the first station and begin preparing the solutions.
During this step you should:
- Have resource persons who have mixed these solutions observe, correct and assist the participants with any problems or questions they nay have. Also tints person should make sure everyone uses proper hygienic techniques when mixing the solutions (e.g. washing their hands and all utensils before and after making the solution).
Step 5 (30 min.)
Discussing The Use of Oral Rehydration Solutions in The Village
Reconvene the group and ask each small group to report on their experience at one of the stations. Have someone from each group record the answers on newsprint, using the format from Handout 5A (ORT Preparation Worksheet). Allow about 5 minutes for each work station report. Encourage comments and discussion after each presentation.
Ask participants to think about what they have learned and answer the following questions:
- Which treatment should be used when a child has diarrhea? Some signs of dehydration? severe dehydration? Why?
- What problems do you foresee in preparation and use of ORS in the village? What about sugar salt solution?
- What can you do to overcome some of the problems encountered in teaching and encouraging people to prepare and use these solutions?
Be sure to discuss the following kinds of problems:
- Lack of understanding in the village about the importance of accurate measuring.
Make sure that everyone understands the difference between preventing and treating dehydration sad recognizes the need for the potassium and sodium bicarbonate or trisodium citrate (In the ORS packets) for treating dehydration.
Emphasize the importance of adapting the sugar-salt solution recipe to use locally available ingredients and to amounts appropriate for the utensils available for measuring.
Trainer Attachments 5F (Oral rehydration with Dirty Water?) and 5G (A Pinch of Salt, a Handful of Molasses) discuss some of these problems and describe ways to deal with thee.
Following this step you may want to use the optional step
(Discussing Drugs Used to Treat Diarrhea).
Step 6 (45 min.)
Practice in ORT
Demonstrate how to give oral rehydration solution to an infant, Including what to do if the infant spits up the solution or is reluctant to take it. Have one of the participants do a return demonstration.
If possible, give all the participants an opportunity to give the solution to an infant or child during or after this session.
After they finish practicing, discuss problems encountered and ways To overcome them.
Step 7 (15 min.)
Ask the participants to summarize the key points that should be taught about rehydration solution preparation and administration in the communities and how they would do this.
Information that they should include on how to educate community
and family members about home treatment of diarrhea can be found in The WHO
Supervisory Skills Module, "Treatment of Diarrhoea" pages
Optional Step (15 min)
Discussing Drugs Used to Treat Diarrhea
Depending on the health background and task assignments of the participants, you nay want to use Trainer Attachment 5H (Cautious Prescription) and page 55 of Treatment of Diarrhoea to discuss the types of diarrheal diseases that do require drugs in addition to oral rehydration.
- What kinds of drugs are commonly used to treat diarrhea in this country?
- Why is this use of drugs dangerous?
- How can we overcome the idea that drugs are the best cure for any kind of diarrhea?
- What do people in your communities think about the power and/or danger of medicines?
- Who should decide whether a drug is needed to treat a case of diarrhea?
Emphasize that drugs should be "cautious prescriptions.. They should be given cautiously and only when there is a clear indication (such as bloody stools and high fever) that the cause of the diarrhea is a disease that requires drug treatment. They should be prescribed by a qualified health worker. Drugs should never be given as a routine practice for treating diarrhea. A drug that is not needed can be harmful to the body in a variety of ways; giving the drug is likely to divert the mother's attention from oral rehydration, widespread use of drugs promotes the development of drug-resistant strains of diseases; and antibiotics are expensive.
You nay want to assign two people to visit a local pharmacy or
store to ask about and get samples of drugs commonly used to treat diarrhea in
the host country. You can ask them to report their findings at the beginning of
Observation Items (1-8)
Pre-packaged Solution (ORS)
Homemade Solution (sugar, salt)
1) List of Solution Ingredients and Amounts
2) Availability of ingredients
3) Length of Time for Solution Preparation
4) Difficulty of Instruct ions for Solution
5) Problems in Solution Preparation
6) Materials (Equipment ) Needed to Prepare Solution
7) When to Use the Solution (Treatment Plan A or B?)
The set-up for Stations. 1 and 2 is intended to permit participants to learn how to prepare two kinds of oral rehydration solutions under organized, clean conditions, wing local utensils and measures. Modify these preparations to fit government standards for ORT preparation.
If the training is conducted at a regional site near a community, you may want to arrange opportunities for participants to mix ORT solutions in local homes, under the supervision of someone skilled in mixing ORT.
Both Stations should have:
- soap and water for handwashing,
- clean water for mixing the solution,
- ladle or means of drawing water,
- hand towels,
- spoons or utensils for stirring,
- drinking glasses or cups for tasting solution.
- large (over 1 liter) container to use in stirring the solution
Station 1: Pre-packaged Solutions
- Proper size containers (usually over one liter but marked to give volume corresponding to exactly 1 liter) for mixing packets and water
- Local containers that approximate 1 liter
- Enough Packets for all participants to mix the solution
- Mix the solution in the marked container and pour it into the local container.
- Note hoc closely the local container matches the volume of the marked container and what problems this could cause.
- Complete the ORT Preparation Worksheet (column one) this station.
Station 2: Homemade Solutions: Sugar and Salt
- Proper size local container and marked container for mixing.
- Measuring spoons
- Plenty of salt and sugar (If baking soda is available and is part of the government standards for mixing ORT solutions, include it)
- Knife for leveling measurements
- Weighed, labeled correct amounts of ingredients fusing the WHO recommendations).
It the government standard measurements are the handful and the pinch, have participants compare the weighed amounts of ingredients with their own "handful" and "pinch." This reduces variation in measurement resulting from differences in hand size and perceptions of what constitutes a handful or a pinch. Be sure to include the weighed ingredients in your demonstration. Stress the importance of accurate measurement.
If locally available salt is very coarse, provide a means to grind it for more accurate measurement.
- Measure and mix the solution.
- Compare your measured amounts with the samples of ingredients that were weighed exactly.
- Complete the ORT Preparation Worksheet (Column two). Give particular attention to " problems in solution preparation. and how they could affect the success of mixing ORT solutions in the home.
Below are two examples of simple ways to present the idea of rehydration. See Helping Health Workers Learn, Chapter 24, pages 17-22 for additional ideas.
Plastic Beg Model
Take a clear plastic hag with no tear or bole in it. With a felt-tip pea (the kind with waterproof ink) draw a picture of a baby on it. Fill the bag with water; the picture of the baby will be full and well-rounded, like a healthy child. Now make a small hole la the lower part of tee bag with a pin. As water flows out, the bag and the picture will become wrinkled. This shows what happens to a child who has diarrhoea and becomes dehydrated.
Ask a trainee to pour water into the bag faster than it is flowing out of the hole. This shows what happens with oral rehydration; the picture of the baby will become normal again. Now seal the hole with a piece of tape or sticking plaster so that the water stops flowing out. This shows that the diarrhoea has stopped and no more rehydration is needed.
To learn about dehydration, the children can conduct their own experiment by making a gourd baby' like this one:
How can dehydration from diarrhea be prevented?
They learn that, as long as all the lost water is replaced, the water level will never go down and the baby will not become dehydrated.
A child with diarrhea needs to drink at least 1 glass of liquid each time he has a watery stool.
Giving lots of liquid to a baby with diarrhea may at first increase the amount of diarrhea. But this is all right. Usually the diarrhea will soon get better. The important thing is to be sure that the child drinks as much liquid as he loses.
(From: Bower and Werner. Ch. 24 pp. 18-20. And WHO, Guidelines for Training Community Health Workers in Nutrition. P.111)
- Oral Rehydration Therapy (ORT) For ChIIdhood Diarrhea (ORT Resource Packet. pp. 43-44.
- Trainer Attachment 5 (The Scientific Basis for Oral Rehydration Therapy)
1. Diarrhea upsets the body's chemical balance and its' ability to process and absorb eater and nutrients.
When the child is healthy, the lining of his or her intestines transforms food into a tore that can be absorbed and transported by the blood stream to all parts of the body. These nutrients provide energy and enable growth. The blood stream is also the source of the minerals and water needed by the intestine to transform the food into a useable form. The intestine "borrows" and returns water and minerals as it processes food. This chemical balance is upset during diarrhea.
Diarrheal diseases affect the functions of the intestines. During diarrhea, the small intestine loses its ability to absorb water and essential minerals called electrolytes (sodium chloride, potassium, and bicarbonate). Minerals and water needed to process food leave the body in the child's stools, depleting the body's store of these vital elements and the nutrients they help process.
2. Water and electrolye loss cause the physical signs and symptoms recorded on the WHO Treatment Chart.
Fluid and mineral loss of greater than five percent, but less than ten percent of body weight generally causes a weak rapid pulse, loss of skin elasticity, low blood pressure, severe thirst, and other signs noted in Column B of the WHO Diarrhea Treatment Chart.
A loss of more than ten percent of the body weight results in shock, stupor, disrupted kidney function, acids build up in the blood (acidosis), peripheral blood vessels collapse, and death follows (see Treatment Plan C on the WHO chart.
3. Infants and small children are nor- susceptible to dehydration from diarrhea.
Infants and young children are particularly susceptable to dehydration from diarrhea, because of their small body weight For example, it a child who weighs ten kilograms loses one kilogram of water, ho or she has lost ten percent of the body weight and is severely dehydrated.
4. Oral Rehydration Salts (ORS) restore the body's chemical balance, and replaces the water lost.
Oral Rehydration with ORS (Oral Rehydration Salts) replaces the blood's electrolytes nearly as quickly as they are lost in the stool. This is due in large measure to the special ability of glucose to increase the absorption rate of sodium through the intestinal lining.
ORS includes all the essential electrolytes. Sugar and salt solution only has one of the three. This is why it is necessary to give ORS to a mildly dehydrated child.
Summarized below is the formula for the new trisodium citrate ORS. The ingredients for the other solutions are stated in The Treatment of Diarrhoea, p.17 and 42.
ORAL REHYDRATION SALTS (ORS) FORMULATION CONTAINING TRISODIUM CITRATE
1. In 1982-1983 the WHO Diarrhoeal Diseases Control (CDD) Programme supported laboratory studies to identify a more stable ORS composition, particularly for use in tropical countries, where ORS has to be packed and stored under climatic conditions of high humidity and temperature. The results of these studies demonstrated that ORS containing 2.9 grams of trisodium citrate dihydrate in place of 2.5 grams of sodium bicarbonate (sodium hydrogen carbonate) was the best of the formulations evaluated1. The formulae of the standard ORS (ORS-bicarbonate) and ORS containing trisodium citrate dihydrate (ORS-citrate) are shown below:
Sodium bicarbonate (sodium hydrogen carbonate)
Trisodium citrate dihydrate
SUMMARIZE by stating that Oral Rehydration Therapy is used to:
· Replace fluids
· Restore the chemical balance of the body.
ANALOGIES THAT HELP LEARNERS UNDERSTAND THESE CONCEPTS:
To give participants a more concrete sense of what it means to lose chemical balance, ask someone to stand on one foot and hold objects of equal weight in each hand. Then ask them to remain on one foot but hold both objects in one hand. Ask thee to tell the others hoe that feels to go from a balanced to an unbalanced situation. How well can they function in this states This can provide the basis for discussion.
To convey the idea that children are particularly vulnerable to dehydration from diarrhea, put the sane amount of water in a large cup and in a small cup. Ask participants to compare the cups. Use this as a basis for discussion.
DR. NORBERT HIRSCHHORN
John Snow Public Health Group Inc.
National Control of Diarrheal Diseases Program
When a child has diarrhea it loses body fluids - mainly essential minerals and water - and becomes dehydrated. So mix up some salts and sugar in water, and feed the solution to the child, as much as he/she will take until the child is no longer dehydrated, and diarrhea has slowed down or stopped. Make sure the child continues to take food or breast milk.
This is oral rehydration therapy, and it seems so simple (compared, say, to manipulation of genes or artificial hearts) that one may wonder what science has had to do with ORT, or why we need continue scientific studies on ORT. Many older physicians, nurses, or mothers have protested, "This is nothing new, we have been practicing ORT for years" Some of the great clinicians wrote about ORT thirty to forty years ago - Darrow, Harrison, Chatterjee. But this is precisely the point: they wrote about using ORT, but did not know how ORT works (nor to be fair, could they have them and so there was no further development or spread of their anecdotal experience until some decades later. Even today, when we fail to understand and use the scientific approach, we continue erroneous or wasteful methods of therapy; actually, this is the case in all fields of medicine and public health. Not everyone who practices ORT must be a scientist, but the spirit of inquiry and joy of discovery which suffuses science may be shared by all. The spirit of inquiry is present in five stages:
1. Observation - using all one's senses to capture events and think about them: it was noticed that children with dehydration drank the oral rehydration solution vigorously and greedily and, when nearly hydrated, slowed down and often went to sleep.
2. Measurement - taking one's observations and gauging some values on scales of time, length, amount, and degree: children who drank oral rehydration solution at will tended to drink close to what their initial deficit was, as measured by intake, output, and change in body weight.
3. Creative hypotheses - thinking through the implications of a measured observation and asking interesting questions: who can choose more closely the correct amount of fluid for rehydration, the dehydrated child or the physician?
4. Testing experimenting - within the ethical boundaries of conduct, designing, with proper statistical force and safeguards against bias, a test of the hypothesis: in certain situations, children freely drinking oral rehydration solution became hydrated faster and reached better fluid and mineral balance than those on intravenous solutions controlled by physicians.
5. Application - using the results of scientific testing for the widest possible benefit. It is as Jon Rohde and Robert Northrup have written, "taking science where the diarrhea is" Human information must be shared across all political and other boundaries.
The data and information I will present in this paper have gone through several of these five stages of scientific inquiry.
ORT developed from two streams of inquiry, if I may use a liquid metaphor. The first established what dehydration actually meant, how it related to the clinical picture of the dying child, and what was needed to reverse the situation. Believe it or not, this line of inquiry has taken nearly eighty years to come to satisfactory resolution. The second line, still ongoing, is the discovery of how the intestinal tract handles the movement of salts, nutrients, and water between the body and the outside world.
The picture of the dying child is hauntingly familiar. The baby has lost about 10% of its weight in fluid. This amounts to one liter of fluid in a ten-kilogram child, or about a quart in a twenty-two pound baby. Now the child has hollow, sunken eyes; its pulse is feeble or absent; its breathing is deep and rapid; the skin, when pinched, tends to remain dented and inelastic; the abdomen many be distended; urine has ceased to flow; the mouth is parched; the eyelids do not quite shut properly; there are no tears. Dry as the child may be, vomiting and watery diarrhea persist nearly to the end, and this stage may be reached in as little as ten to twenty hours after onset of illness.
Virtually all these signs are due to loss of salt, water, potassium, and sodium bicarbonate, all essential ingredients for life. Most of the loss is in the watery stool, and some, especially in the case of potassium, is from the urine. Regardless of the cause of diarrhea (rotavirus, cholera, E. coli, etc.) or whether in Baltimore or in Bengal, once the child reaches these clinical signs the amount of loss of water and minerals is roughly the same (Table 1) This is fortunate in a way, because the replacement therapy may be uniform and does not require us to know which specific microbe is doing the mischief. Incidentally, while the loss of potassium is of the same magnitude as that of sodium, the body stores of potassium are several times larger. So replacement of sodium is more urgent and also helps conserve potassium.
Although the extreme case I have portrayed is present in 1% to 2% of all bouts of diarrhea, it is sobering realize that with very few visible signs of dehydration beyond thirst, the child may have already lost 5% of body weight, halfway to death, in as little as five to ten hours. By the time parents become alarmed, there may be only a few hours left in which to find competent help. The majority of children who die, however, do linger for two to three days: they have received some fluid, probably of dubious value, by mouth or intravenously; the diarrhea may have slowed a little if various medicines are tried. But by this time the parents may have exhausted their money or the skills and resources of the local practitioner, and the nearest hospital is miles away. The child needs fluid therapy: effective, affordable, trustworthy, nearby.
But we learned about ORT only after we knew how to apply intravenous therapy. Beginning in the mid-1940s, diarrhea research centers in Dhaka, Calcutta, Manila, Cairo, Baltimore, and Taipei proved that intravenous solutions containing sodium chloride, potassium chloride, sodium bicarbonate (or lactate or acetate) in a well-determined combination could be given rapidly so that severely dehydrated children could, Lazarus-like, be resuscitated within two to four hours. Lives are saved by the use of a polyvalent solution, administered quickly with the correct proportion of ingredients. ORT is successful foremost because of this principle, first discovered for intravenous therapy. And we must still rely on intravenous fluids if the child is so severely dehydrated that it cannot drink at all. With this principal exception, what then makes ORT preferable to the intravenous route?
- It can be given by persons with little formal education, even in the home.
- It needs no sterile equipment.
- It is inexpensive (a boon, incidentally, even to well-equipped hospitals)
- It is safer and, under most circumstances, more effective.
- In a pinch, a less-effective formula can be prepared at home from table salt and table sugar (sucrose)
- It allows parents to participate in the care of their children.
- It is comforting to the child and to the parents.
Let us now consider the second stream of inquiry that led to the development of ORT: how the intestine handles salts and water
"What a piece of work is man," given form by skeleton, powered by muscles, coordinated and programmed by a chemical-electric skein of nerves and brain, nourished and defended by a red liquid distantly related to the primordial sea.
The intestine is but a hollow tube connected to the outside world at both ends, the core around which the rest of the body is wrapped. The intestine does many things, but its prime job is to take food, break it into basic molecules that are usable by the body's cells, and transport these molecules across the one-cell-thick lining that separates inside from out. To digest food, it seems necessary to increase the surface area of the tube by multiple folds on the surface of the tube and by fingerlike projections from these folds, called "villa," which carry multiple digestive enzymes at or near their surface. If the surface area is much reduced, as occurs in the disease called "spree," key nutrients and vitamins are not absorbed. It also seems necessary to suspend the particles in liquid and let digestive enzymes do their chemical work. The ultimate source of the digestive liquid is the blood stream, from which the intestine abstracts and secretes salty water free of blood or serum. Secretion of salts and water seems largely to be the function of the youngest cells in the lining, called the "crypt cells" end is controlled by a marvelously organized sequence of enzymes, minerals, and small chemical messengers which ´'know" just when to turn the flow on and off. Infectious agents which cause diarrhea are able to turn the cell mechanisms for secretion to a fixed "on" state until new cells replace the infected ones, usually in two to four days, or until the microbes and toxins are cleared out by the defense mechanisms of the body.
It has been estimated that the intestine of a healthy adult secretes one hundred liters - 264 U.S. gallons - or more of fluid each day; amazing, of course, but, given the total surface area of two million square centimeters (the size of a ballroom carpet seventy by thirty feet), one hundred liters represents but one drop per square centimeter per day Since the well nourished adult body contains only forty-five liters of fluid altogether and the adult would die if just seven to ten liters were permanently lost, there must be a rapid, certain mechanism to put the digestive fluid back into the bloodstream nearly as quickly as it is secreted. In what is surely one of the neater bits of engineering, the very molecules produced by the liquidy digestion are the ones that help transport the salts and water back across the intestinal cell, from there to return to the inner pools of body fluid. The molecules that work this way are principally glucose, the simple sugar derived from starch or table sugar; galactose, a component of milk-sugar; and amino acids and peptides, the products of protein digestion. Each of these molecules combines with sodium, probably in close to a one-to-one ratio, and these dyads cross the cell membrane, per haps by linking in a menage-a-trots to carrier protein molecules anchored in the membrane. Water is pulled along by osmosis, and other minerals (potassium, bicarbonate, more sodium) follow along, caught up in the stream, as it were. Most of this absorption appears to take place in the upper, more exposed regions of the villi, so that if there is extensive damage to villi from, say, viral diarrhea, oral rehydration may fail: failure occurs in about 5% to 10% of seriously ill children.
What is rather elegant about this system is that glucose, amino acids, and peptides seem to enter the cell linked to sodium, but each class of molecules joins with different carrier molecules or finds separate entrances specific to each. One predicts that if one adds an amino acid - glycine, say - to glucose in an oral rehydration solution, more fluid will be absorbed than if glucose or glycine are used alone. This is just what happens, and, as you shall hear shortly, this phenomenon promises a major advance in oral rehydration therapy. But for the moment, let us leave the alimentary canal and return to the child.
The formula for the oral rehydration solution was originally devised to combat epidemic outbreaks of cholera in which both adults and children are affected and where lifesaving intravenous fluids are scarce. The salts are packed in flat aluminum foil packets, paid for and stockpiled by UNICEF ready for shipment to any country on demand. The formula, often referred to as the "WHO formula,' was originally devised as a compromise between what adults needed and children could tolerate. The composition, however, is more inspired than that suggests (Table 2). The amount of salt is sufficient to replace sodium and water losses in severe de: hydration (Table 1), although adults may need to drink extra amounts. Glucose at 2% is optimal, as many studies suggest that water is best absorbed when glucose and sodium are in the ratio of one-to-one, and glucose does not exceed a concentration of 2 1/2%. Potassium deficit is only partially met by this formula because it is unsafe to completely replace losses so fast, but initial replacement must be started quickly (some suggest increasing the replacement rater Acidosis is corrected much faster with bicarbonate than without This formula has proved surprisingly versatile in the treatment of hundreds of thousands of children and adults, with documented success in #5% to 95% of cases, under the following range of situations:
- in persons who are able to drink;
- in malnourished children and the well nourished;
- in bacterial and viral causes of dehydrating diarrhea;
- with serum sodium levels as low as 110 milliequivalents per liter to as high as 165 extremes immediately threatening to life;
- with severe derangement of the blood alkaline-acid balance to the acid side (a condition called acidosis);
- in tropical climates and Baltimore winless;
- with no visible dehydration up to loss of body fluid equivalent to 10% of body weight.
- with voluminous, continuing loss of diarrhea, up to 10 milliliters per kilogram body weight per hour.
Even vomiting does not bar success except in a few instances; in fact, vomiting decreases in direct proportion to the degree of rehydration with ORT what makes ORT so versatile, in addition to its balanced formula, is that most children drink as much oral rehydration solution as is offered up to nearly the amount of which they are deficient. When they are hydrated, or nearly so, they seem to lose their taste for the fluid, then they either fall asleep, or cry for food.
Crying for food: we must think of ORT as more than simply rehydration with a solution of salts and sugar. ORT also means restoration, quickly, of a normal diet. It is now well established that a principal cause of malnutrition in children of the Third World is repeated episodes of diarrhea. The reasons are several and interactive:
- children lose their appetite for food because of salt and water loss and acidosis;
- children are often made to fast when they have diarrhea, sometimes for several days, because it is feared that food makes diarrhea worse;
- potassium loss may make muscle tone too weak for eating and digestion;
- when a child is ill, anxiety and restlessness burn up calories from the child's own stores of fat and protein (which may be already seriously depleted;
- diarrhea and fasting independently damage digestive enzymes in the intestinal tract, leading to malabsorption and loss of food that is eaten.
- with each serious bout of diarrhea, a child loses weight and may never catch up to its potential for growth and good nutrition.
In well-designed studies in the Philippines, Iran, Turkey, India and Panama, ORT appeared to protect against acute weight loss with an episode of diarrhea when the parent was also encouraged to continue to feed the child despite the diarrhea. Breast milk, soft foods and porridges, even fish and fruit and breads were advised. ORT restores a child's appetite u within a few hours, so suddenly this advice made sense to parents. The protective effect was most apparent in those already undernourished, and in those with repeated episodes of diarrhea and protection seemed to last several months. But of course no food, no protection.
We do not know, exactly how ORT works to protect nutrition, but we observe regularly that rapid restoration of fluid and mineral balance restores appetite. Potassium may play a key role here; there is also an intriguing possibility, based on studies of adults who go without food, that the glucose in ORT may help restore or protect intestinal digestive enzymes. The parent certainly finds feeding the child more acceptable, and the child becomes more settled.
Oral rehydration therapy is, thus, two therapies: rehydration and continued feeding. ORT has already been proved to reduce mortality from diarrhea. It would be an amazing achievement if ORT could also reduce the prevalence of malnutrition.
This hope leads me to consider an impending development in ORT. Often, parents" and physicians' prime concern is to stop the diarrhea, and until they see otherwise, they do not believe that rehydration is the first order of business. ORT does not stop diarrhea, which generally runs its own course of a few days; we spend a lot of effort getting that point across. Perhaps we soon will have the means to slow stool loss even while rehydrating the child.
You will recall, back in the alimentary canal, that the different breakdown products, or metabolites, of digestion (sugars, peptides, amino acids) linked up to sodium and promoted salt and water absorption through different gates in the intestinal cell membrane. There is now sufficient evidence that if we combine these metabolites in a single oral solution, we not only rehydrate but can actually decrease the total loss of stool. Peptides and amino acids are particularly necessary in the combination because they act on absorption all along the small intestine, whereas the action of glucose is more confined to the upper portion. Absorption of peptides and amino acids are also far less susceptible than glucose to damage by diarrhea. So the next step is to develop an enriched ORT, one that combines salt, potassium, bicarbonate, glucose or a simple starch, and peptides or a simple protein. Here are some expected advantages of such a formula.
- Diarrhea is lessened.
- With less diarrhea, there will be less waste of nutrients in regular food, and possible more protection of intestinal enzymes.
- Common local foods, already familiar to parents, may be adapted to form an enriched ORT.
Early studies with such a formula are encouraging. We look forward now to a burst of research to define its optimal composition, the range of severity of illness it can be used for, its advantages over the WHO solution and food given separately, its cost and distribution. We will need to consider, also, how we can enlist parents to prepare and use an enriched ORT at home.
Where does all this take us? From a global public health view, it is possible that ORT is nothing more than a palliative until research produces effective antidiarrheal vaccines. Now. sadly, for many children, ORT merely postpones death. Optimists among us hope ORT programs will enable people to trust other health services, such as family planning, to encourage better nutrition and hygienic practices, to improve the health worker's morale, and to help achieve "Health for All".
We hope these hopes prove true; they need testing. But little can be advanced, I believe, as long as nations fail to make human welfare the first priority.
This brings me full circle to the beginning of this paper.
The international agencies sponsoring this conference have done a lot for our children. They support research; they supply services and technicians; through a generous network of information they link scientists from Boston to community health workers in Bangladesh; but most of all they demonstrate that the global village exists: in helping our neighbor's child survive we establish our common humanity.
AVERAGE WATER AND SALT LOSSES IN SEVERE DIARRHEA OF A 10-KILOGRAM CHILD BEFORE TREATMENT (milliequivalents)
COMPOSITION OF THE "WHO FORMULA" FOR ORAL REHYDRATION SOLUTION
Grams per Liter Solution
Chemical Concentration in Millimoles per Liter Solution
Whether a country is producing ORS locally or using UNICEF sachets, the product must be properly stored so that it remains effective from the time it is delivered to the central store to the moment it is used. Sodium bicarbonate causes decomposition of glucose in oral rehydration salt mixtures. High temperatures and humidity may accelerate this process and manufacturers must consider these factors when preparing and packing ORS.
· Temperatures in buildings where ORS is stored should not exceed 30°C. Above this temperature the ORS may melt or turn brown. If this happens, it may be very difficult to dissolve and should not be used. If, however, it has only turned yellow, as long as it can be properly dissolved, it is still safe to use and effective.
· Supplies of ORS should not be stored in buildings with galvanized roofs directly exposed to the sun without adequate ventilation. These rooms get very hot.
· Humidity in stores should not exceed 80 per cent. In higher humidity the ORS is likely to cake or turn solid. Increase ventilation and avoid standing water in or near storage rooms.
· As far as possible, storage areas should be cleared of insects and rodents.
· Packets should be packed so they are protected from puncturing by sharp objects.
· UNICEF recommend storing their ORS sachets in stacks of cartons approximately 1 to 1 1/2 metres high.
· A rotating system should be introduced so that the oldest ORS (identified by date and batch number) is used first. When in a hurry, avoid distributing the packets which are at the front of the top unless you are sure they are the oldest in the store.
· Regional storage areas should be located in places that will be convenient for subsequent distribution.
Regular inspection of packets
· Laminated foil ORS packets have an estimated shelf life of at least three years. Note the production date on the label. Packets of ORS must be checked regularly (every three months) to see if the quality is still acceptable. Open at least one packet in each batch to see if ORS is usable. Locally produced packets of ORS is usable. Locally produced packets of ORS are often packaged in plastic and will probably have shorter shelf life. It is especially important to check them regularly.
· Check ORS packets in any boxes that appear to be damaged. Open at least one packet from the top, middle and bottom of the box to see if the ORS is still usable.
Keeping records at each point where ORS is received and delivered
· Records should show:- the quantity, batch number or letter, and date received.
- the quantity and date issued (i.e. sent from one point in the distribution system to another).
- the amount currently in stock.
- stock level at which a new supply should be requested.
· Records should also indicate any problems (such as spoilage due to a leaking warehouse).
· Supplies should be counted every three months and results compared with quantities shown in the records.
· The evaluation of stock is an important factor in determining future quantities of ORS required.
If you are interested in further information on local production of ORS and quantity control, the following publications are available from the Programme Manager, CDD Programme, World Health Organization, 1211 Geneva 27, Switzerland.
· Guidelines for the production of oral rehydration salts.
· Good practices for the manufacture and quality control of drugs.
(From: Diarrhoea Dialogue, Issue 8, February 1982, p.6)
Many of you have asked about the use of dirty water in making up oral rehydration solution when clean water is unavailable. Richard Feachem suggests that the benefits of early replacement of water and electrolytes in acute diarrhoea far outweigh the possible risk of using contaminated water.
Mothers are encouraged so prepare oral rehydration fluid using only clean water. However, most people in rural areas of developing countries have no access to clean water and in some communities the only available water is heavily contaminated with faecal material(1). In these circumstances it is recommended that the water be boiled and allowed to cool before preparing the oral rehydration fluid. This is often impracticable - involving use of expensive fuel and delaying the start of treatment. If oral rehydration therapy becomes common place in villages it is certain that the ore's rehydration fluid will often be made up with water containing pathogens of faecal origin. Does this matter? The answer is we don't yet know but it probably doesn't.
The main questions
The dirty water used to make up the fluid may contain faecal viruses, bacteria and intestinal parasites. Of these only tile bacteria may multiply if conditions are right. Oral rehydration fluid is normally used for about 24 hours after it is prepared and therefore the two central questions are:
· can certain bacterial pathogens that may be present in water multiply in oral rehydration fluid stored in the home at 20-30°C
· if they can, what is the effect of ingesting a large dose of bacterial pathogens on an intestine already colonized by the same pathogen or by another viral, bacterial or protozoal pathogen
Only multiplication (rather than enhanced survival) of a pathogenic bacterium in oral rehydration fluid is important, since only if multiplication takes place might the child receive a greater dose of the bacterium in the oral rehydration fluid than in plain water.
The results of laboratory experiments are conflicting. Some have found a steady decline in the numbers of pathogens introduced into oral rehydration fluid. On the basis of these findings a WHO Scientific Working Group(2), concluded that "Escherichia coli, Vibrio cholerae, Salmonella and Shigella do not multiply in oral rehydration fluid and survive in declining numbers for up to 48 hours".
This is unlikely to be true in all circumstances and one recent study has shown that V. cholerae and entero-pathogenic and enterotoxigenic strains of E. coli increased in concentration by between 1 and 5 log10 units after 24 hours in oral rehydration fluid. However, all these experiments used oral rehydration fluid made up with distilled water, or with sterilized surface water and therefore failed to duplicate actual field conditions.
A more relevant study on the behaviour of wilds E. cold in oral rehydration fluid made up with well water has recently been reported from The Gambia.(3)
The concentration of E. cold in well water alone fell slightly during 24 hours storage (2330° C). However, in well water plus oral rehydration salts the concentration increased by over 2 log10 units. The same study compared the response of children (three months to four years) receiving oral rehydration fluid made up with well water with those whose fluid was made up with sterile water. There was no difference in the incidence and duration of acute diarrhoeal attacks, or in the growth rates, between the two groups it was estimated that the E. cold ingested in stored oral rehydration fluid were at most 5 per cent of the E. cold regularly ingested in food eaten by these children in The Gambia.
A sound strategy
In conclusion, some bacteria may multiply in stored oral rehydration fluid. There is no evidence, however, that using contaminated fluid increases the incidence severity or duration of diarrhoea, and there is one study indicating that it does not.
A sound strategy, pending more field research, is to advise mothers to use the cleanest water available, to boil it where possible and not to keep the oral rehydration fluid more than 24 hours. To those who express concern at this approach it must be stressed that the proven benefits of water and electrolyte replacement early in acute diarrhoea far outweigh the possible risk of using contaminated water.
(1) The Lancet, August 2 1980 pp 255-256
(2) Report WHO/DDC/79.3
(3) Transactions of the Royal Society of Tropical Medicine and Htgyene, 1980, Vol. 74, pp 657-662.
In remote Sulla, a deprived area of Sylhet district in Bangladesh, an epidemic of diarrhoea among young children prompted an emergency do-it-yourself solution. That "solution" - salt, water, molasses - has proved a saviour of children's lives. By MEHR KAMAL
Sulla, a low-lying tract in Bangladesh's Sylhet district, is one of the poorest areas in the world. Here, farmers wrest one rice crop a year out of tiny plots of land. Most people, however, are landless and find only seasonal employment as farm hands or as fishermen when the rain-swollen rivers spill over, converting the marshy area into a vast monsoon lake.
So remote and neglected is Sulla that few Bangladeshis have heard of it. In 19 72, when a local non-governmental organization, the Bangladesh Rural Advancement Commitee (BRAC), began rehabilitating destitute refugees returning home after the creation of Bangladesh, it chose Sulla as a base of operations because of its extreme deprivation.
But BRAC workers arriving there were immediately faced with another more urgent problem as a diarrhoea epidemic broke out and hundreds of children began to die of dehydration and malnutrition. With no health services or pharmacies to rely on for support. in dealing with the problem) they prepared oral rehydration solutions for the children with salt, molasses and water, all of which were available even in the poorest homes.
This simple treatment - approved by the International Centre for Diarrhoeal Disease Research in Bangladesh (ICDDRB), the world's leading institution for research on diarrhoeal diseases-and BRAC'S method of teaching mothers how to use it, are now generally recognized as the best hope for an early reduction in infant deaths in Bangladesh.
Of every 1,000 children born alive in the country, some 140 die before reaching their first birthday, approximately half of them from complications such as dehydration and severe malnutrition connected with diarrhoea. While not a serious problem in itself, since the body purges itself of most diarrhoeal infections without any medication, diarrhoea can be devasting to a small child because essential fluids, minerals and nutrients are sometimes expelled from the body in a day. In Bangladesh, most of the 17,000 children who lose their eye-sight every year do so because diarrhoea drains away their already meagre reserves of vitamin A.
The treatment for diarrhoea is simple. A solution of salt, glucose and electrolytes mixed with water and taken orally can help to reverse dehydration. In Bangladesh, the Government is packaging oral rehydration salts (ORS) at four national centres assisted by UNICEF. These are then distributed free through the health services, and commercially-produced ORS packets are sold in dispensaries.
The total national production of ORS is not enough to meet the need. But stepping up production would address only a small part of the problem of getting mothers to use ORS when they should. In one of the world's least developed countries, health services reach only 21 per cent of the people and the nine out of ten people who live in rural areas have no access to pharmacies because these exist only in urban or semi-urban areas.
In addition, only 14 per cent of Bangladeshi women are literate and thus able to read the instructions for mixing the solution. At prices ranging from a few cents to over one dollar a packet, the cost may also be prohibitive, since the annual GNP per capita is only US$110, and four out of every five people live below the official poverty line.
Overcoming the hurdles
In Sulla, BRAC devised a programme which overcame ail of these hurdles. Since the accurate measurement of ingredients is crucial to the success of the therapy, it chose the method that most rural South Asian women use in measuring ingredients for cooking: their fingers.
The only spoon available in many homes is a wooden ladle used for stirring and serving, and women judge the proportion of spices required by pinches and heaps. BRAC therefore suggested a three-finger pinch of salt and a handful! of molasses mixed with an appropriate quantity of water.
Next, BRAC concentrated on one of the most difficult aspects of the problem: a change in attitudes and ingrained habits. Many Bangladeshi women believe that diarrhoea is either an air-borne affliction or is caused by evil spirits. So they hide the problem until it becomes severe. Doctors at the ICDDRB say that, at this stage, death can be only hours away, particularly for under-nourished children. Dehydration is accelerated by the fact that most mothers deny their children food and water during diarrhoea in the hope that this will stop the runny stool.
BRAC devised a simple flip chart which explained the connection between diarrhoea and dehydration by likening a child suffering from diarrhoea to a pitcher of water with a hole in the bottom. Armed with these, a ream of seven girls, who received five days training in diarrhoea management, went from house to house in Sulla, stressing the importance of rehydration from the moment the first loose motion begins.
With ingredients provided by the mother, they demonstrated the proper way to prepare a solution in a utensil available in the home. At the end of the session, the inside of the container was scratched to mark the appropriate water level, and a discussion ensued on the prevention of diarrhoea.
Each team was preceded by male workers who talked to the men about diarrhoea, and the "doctor" who will come to teach mothers how to treat it. Such persuasion was crucial to gaining the confidence of the community and giving the female workers access to all families.
One of the workers, 23-year-old Rooma, says that while mothers almost always accept the treatment, persuading them to take appropriate steps to prevent diarrhoea is hard. She cites the case of Mumtaz Begum whom she has just visited.
Mumtaz is one of the very few rural Bangladeshis lucky enough to have access to both a tubewell and a latrine. Yet, ignorant of the connection between clean water and sanitation and her children's frequent diarrhoea, she uses neither. The tubewell water is rejected because its high mineral content gives it a "peculiar" taste and the latrine her brother constructed when he came home for a visit from Dubai is regarded as a quaint city facility.
When pressed to wash her hands frequently with soap, Mumtaz said that her husband who sells vegetables in the village earns only Taka 30, U.S. $1.20, a day. This, supplemented with occasional remittances from Dubai, is barely enough to buy food. At 20 cents a bar, soap is a luxury they cannot afford on a daily basis.
In Bangladesh, diarrhoea will continue to be a major health hazard as its prevention requires the installation of millions of new tubewells and latrines, as well as a massive health education effort designed to motivate people to use them. The BRAC method of oral rehydration therapy with its home-made solution and house-to-house instruction is therefore winning widespread support. The experiment begun in Sulla, was extended in 1980 to cover five districts. In October 1983, it will enter its second phase, covering another seven of the country's 20 districts by June 1986.
It will take time to wipe out the agony of diarrhoea in Bangladesh, a land where medical historians believe cholera was reported for lee first time ever in the seventeenth century. But random surveys of its own programme carried out by BRAC have shown very positive results. Three months after receiving initial instructions, some 90 per cent of mothers have been able to answer all questions about diarrhoea correctly, and approximately 82 per cent have been able to prepare accurate oral rehydration solutions. Mizanur Rehman Chaudhry, BRAC'S area manager in Sylhet, claims that, at the cost of Taka 7 (U.S. 29 cents) per mother trained, this could be the most cost effective health programme anywhere.
Professor Harold explains the clinical situations which justify the use of drugs in addition to oral rehydration therapy.
Two main groups of drugs are commonly prescribed in the treatment of diarrhoeal diseases:
· Antimicrobial drugs - which kill the responsible organism and so lessen the illness.
· Antidiarrhoeal drugs - which diminish the amount of fluid loss by various pharmacological mechanisms.
These two types of drugs are often combined and many preparations are marketed containing both antibiotics and antidiarrhoeal drugs. These combination drugs should never be used.
Only single drugs should be given and only where appropriate.
Antibiotics in bowel infections
For certain specific infections of the gut an appropriate antimicrobial drug is an important part of the treatment.
Shigella infection: in mild, transient diarrhoea caused by shigella, antibiotic treatment may be unnecessary as, for example, in mild Sonne or flexneri dysentery. Antibiotics are, however, an essential part of the treatment of severe bacillary dysentery especially in infants with persistent high fever. Choice is difficult because transferable drug resistance has become very common in these organisms and local knowledge of their drug susceptibility has to be taken into account. Ampicillin or co-trimoxazole are usually suitable (ampicilin 100 mg/kg/day in four divided doses for five days, or trimethoprim 10 mg and sulfamethoxazole 50 mg/kg/day in two divided doses for five days). Single dose treatment in adults with tetrad cycling (2.5g) is also very effective if the bacilli are known to be susceptible to this drug.
Campylobacter infection: Campylobacter jejuni may invade the bowel wall causing abdominal pain and mildly dysenteric stools. Most cases recover well without chemotherapy. Severe cases may be treated with erythromycin (40 mg/kg/day in three divided doses for five days) but its efficacy is unproved. A recent controlled trial showed no clinical benefit from erythromycin but treatment was not started until an average of six days from the onset of illness. (1)
Cholera: Several antibiotics, particularly tetracycline, have been shown to shorten the duration of the disease and are therefore useful in the management of cholera patients. Tetracycline is given as 50 mg/kg/day in four divided doses for three days. Drug resistance is now being seen in areas where mass chemoprophylaxis has been carried out. Alternative drugs include furazolidine and chloramphenicol.
Enterotoxigenic and enteropathogenic E. coli: Relatively few clinical trials have been done on the effect of antibiotics in this group of bowel infections. Enterotoxigenic E. cold generally cause acute episodes of relatively brief duration, making antibiotics unnecessary. Because of the difficulty in identifying these organisms, there seems to be little justification at the moment for treating them with antibiotics. Similarly, for enteropathogenic E. coli, there is no clear evidence that antibiotics are beneficial
Salmonella infections: For the vast majority of acute diarrhoeal illnesses caused by nontyphoid Salmonella strains. antibiotics do not change the course of illness and may actually prolong the period during which stool cultures remain positive. Salmonella septicaemia. which may present in childhood as a combination of diarrhoea with systemic illness and fever requires antibiotic treatment. Ampicillin, chloromycetin, or co-trimoxazole may be used, depending on the sensitivity of the organism.
Amoebiasis and Giardiasis: Both these parasitic infections respond to several antimicrobial agents. Metronidazole is the first choice for either.
Antibiotics in bowel infections of unknown cause
The cause of many bowel infections is never identified, or the organism may be found after the acute illness is over. Antibiotics have no role in the treatment of the large group of viral diarrhoeas. It has sometimes been suggested that antibiotics should routinely be prescribed in case the illness turns out to be due to an infection for which antibiotic treatment is indicated.
This practice is to be avoided for several reasons:
· The giving of antibiotics may divert the attention of mother and nurse from the essential task of replacing water and electrolytes.
· The widespread use of antimicrobials promotes the selection of antibiotic resistant strains and thus lessens the likelihood that the drugs will later be effective for those few patients who need them.
· Antibiotics are expensive.
The balance of factors therefore clearly lies against the blind use of antibiotics in diarrhoeal disease of unknown origin.
Other drugs in gastroenteritis
The most commonly used agents are kaolin and pectin in one or other of many available preparations, despite clinical trials proving lack of efficacy. Most children improve so quickly with fluid and electrolyte replacement that the use of 'constipating agents is unnecessary in acute diarrhoea.
Drugs such as opiates, diphenoxylate and loperamide which reduce bowel motility. although widely used, should never be given to children. By slowing peristalsis they make the situation worse - this has been seen in a number of children and in volunteers with shigellosis. These drugs also depress respiration and are an important cause of accidental poisoning in childhood
Several research projects arc underway aiming to find drugs which will reduce the abnormal transport of fluid across the small bowel mucosa. For example, anti-inflammatory drugs (aspiring and indomethacin) may decrease the action of cholera and other toxins acting on the trowel. Bismuth subsalicylate, in large doses, has been beneficial in adults with travellers' diarrhoea.
Other substances have also been tried; for example, chlorpromazine, which probably inhibits adenylate cyclase, was shown to reduce diarrhoeal losses in cholera. However, since it may cause drowsiness in children and hence a decrease in fluid in lake. it is unsuitable for widespread use Attempts have also been made to prevent cholera toxin binding to the bowel wall, but these studies have not shown the method to be useful in practice.
None of these experimental drugs have reached a stage where they can be recommended for general use in patients with diarrhoea. If drugs which reduce intestinal secretion become better defined, and can be shown to be effective in field conditions against diarrhoea caused by 8 broad range of aetiologic agents, they will be useful adjuncts to therapy.
Oral rehydration therapy- remains the essential treatment and antibiotics arc useful only in the few clinical situations described.
Professor H.P. Lambert, Communicable Diseases Unit, St.
George's Hospital-London UK.
(1) Andres BJ et al 1982 Double-blind placebo controlled trial of erythromycin for treatment of campylobacter enteritis. The Lancet January 16: 131-132
(From: Diarrhoea Dialogue, Issue 8, February 1982, pp.4-5)