Prevention and Control of Diarrheal Diseases

Mary Anne S. Baysac & Mark Beilstein, Fall 1999, IH 887

PowerPoint Presentation

Introduction

Diarrheal diseases are a global problem. Along with acute respiratory infections, it is the leading cause of death for children less than five years of age.1 According to Harrison’s Principles of Internal Medicine, an approximate 5-8 million persons of all ages die of diarrheal diseases.2 Moreover, diarrheal diseases are a major cause of morbidity and mortality in infants in the developing world.3 Eighty-five percent of diarrheal deaths occur during the first year of life,4 and approximately 4.6 million children under the age of 5 in developing countries die from diarrheal diseases each year.5 The driving force behind these deaths is dehydration; however, nutrition is a major side effect.

Diarrhea is characterized by three or more watery or loose stools within a 24-hour period. 6 There are three different types of diarrhea:

Dysentery diarrhea causes bacterial damage to the intestinal mucosa. In the gut, pathogenic toxins are released causing cell and tissue death. 3 Tissue layers deteriorate and blood is present in the feces. Symptoms include rapid weight loss and anorexia and this diarrhea can be fatal. 7 (An example of dysentery is Shigellae).7

Acute Watery diarrhea has an acute beginning. Although it usually lasts less than seven days, it can often last up to 14 days. 3 Acute Watery diarrhea involves the passing of frequently occurring watery stools without any visible signs of blood. The stool is clear and termed "rice water stool" because it looks like rice water. 7 Of the three types, Acute Watery is the most common killer; however, one hundred percent of these deaths are preventable by standard case management. 8 (An example is Cholera). 7

Persistent diarrhea is parasitic and can last for unusually long periods of time (at least 14 days. Often, it begins as either acute or dysentery and once present in the gut, it is difficult to remove. Significant weight loss is expected with the diarrhea looking like the food ingested. (An example is Cryptosporidium.) 7

 

Etiology and Transmission

The etiologic agents that cause diarrhea in both developing and developed countries are the same. These agents span from bacterial, viral, protozoan, and parasitic, and they demonstrate a wide spectrum of clinical severity. Rotavirus, a bacterial agent, is the major cause of severe dehydrating diarrhea in the first two years of life in both developing and developed countries. 3 Other diarrhea-causing agents include Salmonella, Shigellae, Campylobacter jejuni, Vibrio Cholerae, and Escherichia coli, which are all bacterial pathogens. Protozoan pathogens include Giardia and Entamoeba. 5

These etiologic agents are mostly spread by physical contact with infected feces, eating or drinking contaminated food or water, or person to person relay. 5

 

Pathophysiology

Deaths from diarrhea are largely due to dehydration and not the bacterial infection itself. As a result, one of the most effective remedies is maintaining a good fluid balance while waiting for the bacterial infection to clear. In most cases of diarrhea, maintenance of hydration, in addition to bacterial specific remedies, would be the proper treatment. There are, however, clear exceptions to this such as Shigellae, where antibiotic treatment would be necessary. 7

 

Factors increasing the risk of diarrhea diseases:

Socioeconomic factors such as overcrowding, poor sanitation, contaminated water and inadequate food hygiene, were associated with a high incidence of diarrheal diseases in early infancy in several studies. 3 Similar findings related to poverty found higher attack rates of diarrhea in poor areas versus prosperous areas. Risk factors include socioeconomic deprivation manifested by household crowding, low maternal education, and low birth weight. 3 Behavioral factors include failure to breast feed exclusively for the first 4-6 months of life, failure to continue breast feeding until one year of age, using infant bottles which are difficult to clean, storing food at room temperature, failure to was hands, failure to dispose of feces hygienically, and drinking contaminated water. 3

Immunosuppression is another factor linked to higher rates of diarrheal diseases, as well as an episode of measles. Of all infectious diseases, the diarrheal diseases have the greatest adverse effect on the growth of children. This is the result of factors such as malabsorption of nutrients caused by the infectious process in the gut and reduced dietary intake resulting from anorexia and from food withdrawal during diarrhea. This is a consequence of traditional practices and improper advice from health workers.3 Malnourished Children in turn have more severe diarrhea, setting up a vicious circle which often leads to persistent forms of diarrhea, with high-case fatality rates and long lasting effects on the quality of life. 5

 

Symptoms of Diarrhea:

As dehydration increases, signs and symptoms develop. These include thirst, restless or irritable behaviors, dry mucous membranes, decreased skin turgor, sunken eyes, sunken fontanelle (in infants), absence of tears when crying vigorously, moist and pale hands and feet, no urine flow for several hours, and drinks poorly. 5,9

 

Prevention:

A number of measures can prevent diarrhea diseases from manifesting. These measures include 1) breast feeding, which provides infants the antibodies to protect against infection, 2) improved weaning practices, 3) proper use of water for hygiene and drinking, 4) hand washing, 5) disposing of feces properly with well maintained latrines, 6) Measles vaccinations, which decrease measles episodes transitively reduce the risk of developing diarrhea, and 7) proper nutrition. 3,5,10

In order to implement these preventive strategies, we must educate people about proper practices and utilize the community health workers and village health workers to enforce such measures.

 

Case Management

There are three main types of therapy used in the case management of diarrhea: oral rehydration therapy, nutritional therapy, and drug therapy.

 

Oral Rehydration Therapy

Oral rehydration therapy (ORT) generally refers to the management of diarrhea through oral administration of water and electrolytes to replace existing losses. 11 This is primarily accomplished by giving an oral rehydration salt (ORS) solution.

There is evidence that ORT was an ancient traditional practice. However, ORT was not used by modern health professionals until the 1960s and 1970s. Research in the 1960s demonstrated that the addition of glucose to salt solutions resulted in absorption of salt and water across the intestinal walls. In the absence of glucose, no absorption of salt or water was observed.11 Soon after, in the 1971 Bangladeshi war for independence, a severe cholera outbreak in refugee camps led physicians to administer ORT using a mixture of table salt, sugar, baking soda and water. As a result of this intervention, mortality rates from diarrhea in refugees decreased dramatically from 30% to less than 3%.12 In 1978, The British medical journal, The Lancet, declared ORT to be "potentially the most important medical advance of this century." 13

The WHO and UNICEF have endorsed the use of oral rehydration salt (ORS) solutions as the standard therapy for the case management of diarrhea. The standard WHO/UNICEF ORS formula consists of :

Glucose (sugar) 20.0 grams

Sodium chloride (table salt) 3.5 grams

Potassium chloride 1.5 grams

Trisodium citrate, dihydrate 2.9 grams

(formerly sodium bicarbonate, 2.5 grams) 12

Currently, two-thirds of ORS packets produced annually are produced locally in 60 developing countries. UNICEF produces the remaining one-third. 12

Homemade ORS solutions, consisting of water, salt, and sugar, are equally effective as the standard ORS packets. Recommended ingredients of homemade ORS solutions include a "three-finger" pinch of salt, and a "fist-full" of sugar or molasses, combined with a liter of water. 14

 

Nutritional Therapy

In addition to ORT, appropriate feeding during episodes of diarrhea is recommended. Laboratory and clinical studies have shown that continued feeding during episodes of diarrhea leads to outcomes in diarrheal diseases. 15 These improved outcomes include: decrease in stool output; shortened duration of illness; significant weight gain; and improved nutritional status. 15

Recommendations for nutritional therapy depend on the age and diet of the child. For infants, the importance of breast-feeding is stressed. WHO recommends exclusive breast-feeding for the first four months of an infant's life, six months if possible. 11 When mothers breast-feed there is a dramatic decrease in episodes of diarrhea. 15 Breast-feeding should be supplemented with ORT. For bottle-fed infants less than six months of age, dilute formula in combination with ORT is recommended. 15 For children who have a regular food diet and experience episodes of diarrhea, continuation of a regular diet is advocated. This should include easily digested foods such as complex carbohydrates (rice, potatoes, bread), lean meats (e.g. chicken), yogurts, fruits, and vegetables. 15

Scientific research has suggested a relationship between diarrhea and specific micronutrient deficiencies. 15 Zinc deficiency may cause diarrhea because zinc assists in absorption of water and salts across the intestinal wall. 15 Vitamin A deficiency is associated with increased risk of diarrhea, and folic acid may be associated with improved recovery time from acute cases of diarrhea. 15 More research into the mechanisms of these associations is needed before micronutrient supplementation can be recommended for the management of diarrhea.

 

Drug Therapy

It is strongly recommended that drug therapy of diarrhea be avoided. There are several potential problems managing diarrhea with drug therapy. Drugs may be potentially toxic to some patients, leading to adverse reactions. 3 Another potential problem with drug therapy is that non-compliance with therapy could lead to antibiotic resistance. 3 In addition, the costs of drug therapy are unnecessary. There is no proven efficacy for the use of drugs in the treatment and management of diarrhea.

Anti-diarrheal drugs are to be strictly avoided. Anti-diarrheal drugs do not prevent dehydration or improve nutritional status. In fact, they can prolong infection and mask signs of dehydration. 16

 

Cost Effectiveness

ORT is less than one-tenth as expensive as intravenous fluid and it is as effective. One packet of ORS costs about 8 cents. An estimated one billion dollars per year could be saved worldwide by appropriate treatment of diarrhea and elimination of drug therapy for diarrhea. 17

 

New Developments

The standard WHO/UNICEF ORS solution has proven highly effective in achieving and maintaining rehydration. However, it does not reduce stool volume, or reduce duration of diarrheal illness. Several "Super ORS" solutions (cereal- and rice-based ORS solutions) have recently been developed. These "Super ORS" solutions reduce stool volume and increase water absorption in the gut. 12

Another new development is a vaccine for diarrhea caused by rotavirus. In the early part of 1999 the United States Food and Drug Administration approved licensure for Rotashield. Produced by Wyeth Lederle Vaccines and Pediatrics, Rotashield was shown to be about 75 percent efficacious in earlier trials. 18

However, in July 1999, the CDC recommended healthcare providers postpone use of the rotavirus vaccine. This recommendation was based on early surveillance reports of intussusception (a type of bowel obstruction that occurs when the bowel folds in on itself) among some infants who have received the rotavirus vaccine. CDC has been collecting additional data to better determine whether the rotavirus vaccine increases the risk of intussusception. A more definitive recommendation by the CDC regarding the use of the rotavirus vaccine is expected by the end of the year. 19

 

Controversies

One controversy surrounding the management of diarrhea is the under-use of ORT and overuse of drugs and IV therapy. The Western medical establishment under-uses ORT and overuses IV therapy in the management of diarrhea. 12 In addition, a large number of physicians prescribe drugs for the management of diarrhea. 12 These practices seem to stem from refusal of the Western medical establishment to re-examine entrenched beliefs regarding the management of diarrhea. 12

Another controversy revolves around the preparation of ORS solutions in developing countries. Some experts advise women to boil water used to make ORS solutions. 12 Opponents argue against the need to boil water. There are several problems with boiling water used to make ORS solutions. The first is that it takes time to heat the water and then let it cool. A severely dehydrated child needs water now. The time delay by boiling water increases the risk of dehydration. Another problem with boiling water is the cost of fuel needed to boil the water. Considering these problems, the argument against boiling water ORS solutions seems justified.

 

References:

  1. http://www.who.int/chd/images/deaths.gif
  2. Friedman LS, Isselbacher KI. Diarrhea and Constipation. Harrision’s Principles of
  3. Internal Medicine, 14th Edition. McGraw-Hill. pp. 236-243 1998.
  4. Claeson M, Merson M. Global progress in the control of diarrheal diseases. Pediatric Infectious Disease Journal. 9:345-355, 1990 
  5. Centers for Disease Control and Prevention. 1992. The Management of Acute Diarrhea in Children: Oral Rehydration, Maintenance, and Nutritional Therapy. http://www.rehydrate.org/html/dia020.htm
  6. Laniken KS, Bergstrom S, Makela PH, Peltomaa M. Health and Disease in  Developing Countries. Macmillan. Chapter 15.
  7. 6. World Health Organization. The Epidemiology and Etiology of Diarrhea. 1998.
  8. Interview with Eugene Millar, Ph.D. Epidemiology Candidate at Johns Hopkins University and former employee of the Center for Disease Control and Prevention. November 7, 1999
  9. World Health Organization. WHO Fact Sheet: Reducing mortality from major childhood killer diseases. Fact sheet Number 180. http://www.who.int/chd/pub/imci/fs_html
  10. What are the symptoms of dehydration. http://www.rehydrate.org/html/faq050.htm
  11. World Health Organization. Prevention of Diarrhea. 1998. http://www.who.int/chd/pub/cdd/meded/8med.htm.
  12. Framm S, Rosemary S. Agents of Diarrhea. Medical Clinics of North America 81(2): 427-447 1997 
  13. Werner D, Sanders D. Questioning the Solution: The Politics of Primary Health Care and Child Survival. Health Rights. Palo Alto, CA. 1997.
  14. Water with sugar and salt. (editorial) Lancet 2: 300-301 1978.
  15. Nova. Child survival: the silent emergency. (video) 1986.
  16. Duggan C, Nurko S. "Feeding the gut": the scientific basis for continued enteral nutrition during acute diarrhea. Journal of Pediatrics  131(6): 801-808 1997.
  17. World Health Organization. The treatment of diarrhea: a manual for physicians and other senior health workers. 1990.  http://www.who.int/chd/cdd/textrev4.htm
  18. . USAID. 1999. http://www.info.usaid.gov/pop_health/cs/csddc.htm
  19. Santosham M. Hopkins: New Vaccine developed for common childhood diarrhea. Health News Zone. Johns Hopkins Health Information – Health News. 1999.
  20. Centers for Disease Control and Prevention, Division of Media Relations. Press 

    21. Release: CDC recommends postponement of rotavirus vaccine for infants. July 15, 1999. http://www.cdc.gov/od/oc/media/pressrel/r990715.htm.