Acute Gastroenteritis:
|
Introduction Children with acute gastroenteritis (AGE) are seen on a daily basis in both the primary care and hospital setting. In Jacksonville, AGE with dehydration was responsible for more than 1500 hospital admissions in the past year. The majority of children are able to tolerate this illness without hospital care, however there is a significant cost in lost work days by parents, multiple visits to doctors offices, the iatrogenic spread through day care settings, and emergency room visits. With careful oral fluid management most children can avoid intravenous hydration and hospitalization. It is our responsibility to be aware of the current guidelines and new therapies, so we may adequately provide anticipatory guidance to parents and help reduce the morbidity associated with AGE. This paper addresses the therapy of oral rehydration, including glucose and rice based-solutions, early, rapid re-feeding versus slow, gradual re-feeding and the more recent areas in research including probiotics and oral immunoglobulins. Oral RehydrationOral rehydration is accepted world wide as the primary tool for management of dehydration in AGE. The availability and use of oral rehydration solutions (ORS) has resulted in a significant decrease in morbidity and mortality associated with acute diarrhea. (1) Oral rehydration therapy (ORT) provides replacement fluids and electrolytes to the dehydrated child. Although the literature supports oral rehydration , it has not been extensively used in the United States. Many reasons for not using oral rehydration therapy include the lack of awareness by practicing physicians, ease of intravenous rehydration in the emergency department, and frustration of parents due to the time consuming nature of ORT. Failure of ORT is rare among well-nourished children. In a review by Lifschitz, the estimated failure rate of glucose-based ORS in developed countries was only 3.6%. In addition, orally rehydrated patients had more favorable outcomes including improved weight gain and shorter duration of diarrhea. (2)Until recently, the classic teaching was correction of dehydration over a 24 hour period. This was felt to be an adequate amount of time for safe correction of electrolytes and fluid deficit. Current recommendations by the AAP for oral rehydration are the correction of mild dehydration (3-5%) with 50 cc/kg of ORS, and moderate dehydration (6-9%) with100 cc/kg of ORS, over 4 hours. For ongoing diarrheal stool losses, 10 cc/kg of ORS should be given for each loose bowel movement in addition to the volume given for correction of dehydration. (3) It is effective to give the ORS in small volumes of 5cc as frequently as every 1 to 2 minutes even in the presence of emesis. (2) An exception to this, is the management of hypernatrernic dehydration (> 150 mmol/L of sodium). Hypernatremic dehydration should be corrected with the same volumes of ORS described above, but over 12 hours instead of 4 hours. This reduces the risk of seizures associated with rapid correction of hypernatremia in mild-to-moderate dehydration. This method demonstrated no evidence for an increased risk of iatrogenic hyponatremia or hypernatrimia associated with oral rehydration. (2) Severe dehydration, defined as dehydration associated with cardiovascular compromise, should be corrected with intravenous fluids rather than ORT. Although ORT has been successful in the treatment of severe dehydration related to cholera in underdeveloped countries, it is not the standard of practice for cardiovascular compromise in the United States. In this instance, an isotonic solution should be used in 20 cc/kg boluses for volume recuscitation. (4) After correction of dehydration over 4 hours, an age appropriate diet should be reintroduced. Oral rehydration does not stop stools and is only necessary in AGE with dehydration. The child with AGE who is not dehydrated should continue a diet which provides adequate nutrition. (3) ORT is well accepted, but the ideal composition of rehydration solution is still being investigated. The most frequently used and best studied solutions are glucose-based, but there are several studies available that support the use of rice-based ORS. Glucose-based solutions aid absorption of fluid and electrolytes from isotonic intraluminal content, but do not aid re-absorption of fluid secreted by intestine or lessen the severity of the diarrhea. (5) These solutions work by glucose stimulation of a sodium transport system that carries water and electrolytes across the intestinal mucosa in the proximal small intestine. This system may carry more than one sodium ion for each molecule of glucose. The most effective concentration of glucose is 2.5%. This allows maximal absorption without surpassing the threshold of the transport system and causing hypernatremic dehydration secondary to osmotic diarrheal stools. Rice-based ORS, on the other hand, does aid re-absorption of fluid secreted by intestine and lessen the severity of diarrhea. It has been suggested that the rice-based solutions work similarly to glucose-based solutions, but provide starch (glucose polymers), protein, and stimulates pancreatic enzyme release that enhances further breakdown of molecules. Together these substrates provide more co-transport molecules that enhance fluid and electrolyte absorption beyond the proximal small intestine reducing stool losses. Two studies compared rice-based ORS to glucose-based ORS. The first study demonstrated a 45% reduction in stool losses by the rice-based ORS group. (6) In the second study, the rice-based ORS group also showed a decrease in the number of watery stools as well as improved weight gain. (7) Rice also demonstrated improved absorption of water, sodium and potassium from the intestinal lumen. (6,7) The addition of rice may also provide superior nutrition during the correction phase of diarrhea. Rice-based solutions are not yet routinely used in underdeveloped countries at this time, but for economic reasons as well as availability of rice in these countries has lead to further Early FeedingOnce dehydration has been corrected, feeding should be re-introduced. Both the technique and value of early feeding in the management of AGE have been well established, but continue to be rarely practiced. Until recently, common practice was therapeutic starvation for 24-48 hours, followed by gradual re-introduction of feeding. This starvation period was thought to allow the gut to recover from the acute illness. (8) However, even short term starvation induces deterioration of the gut mucosa function including reduction of disaccharide levels, decrease surface area, and decrease capacity for fluid resorption. Starvation does usually reduce the volume of stool and thus make intravenous fluid management simpler. Several studies have demonstrated that early feeding improves nutritional intake and weight gain during AGE, but does not prolong the course of illness, and does not increase the risk of lactose malabsorption. (2) A large multi-center study looked at early versus late feeding on the duration and severity of diarrhea, weight gain and occurrence of complications. The early-feeding group was given their regular diet immediatelly following the 4 hour correction of dehydration, whereas the late-feeding group had gradual reintroduction of feeding after 24 hours of ORT correction for dehydration. They found that the complete resumption of a child's normal feeding, including lactose-containing formula after 4 hours of rehydration with glucose-based ORT, led to significantly greater weight gain after rehydration and during hospitalization. This did not result in worsening of diarrhea, increased vomiting, or lactose intolerance compared with the late feeding group. Also, they found there was no significant difference between the two groups in complications during AGE. (9) The idea of early feeding does have relevance in the private practice setting. In fact, one study was done by a group of office based pediatricians who evaluated an unrestricted diet versus clear fluids in AGE. This study demonstrated that dietary manipulation does not affect the outcome of mild diarrhea in the private practice setting. Those who were fed their usual formula tended to have fewer stools, less weight loss and shorter duration of illness. They also found that parents were 90% compliant with an unrestricted diet, but only 30% of the 'clear fluid' group were compliant. (10)
Amino acid solutions that stimulate water absorption are also currently under investigation. It is known that amino acids stimulate sodium and water transport in the intestine and would theoretically enhance absorption of sodium and water, but there is no published data yet available. These amino acid-based solutions may work by similar mechanisms providing more substrates to stimulate absorption. Current research focuses on the physiology of intestinal absorption and newer techniques for rehydration. Areas of active investigation include the addition of fiber, specific amino acids and different polymers of glucose that stimulate intestinal absorption and provide nutrition. Eventually, we will most likely have an ORS that includes all of the above ingredients in a ratio that is most effective at decreasing stool losses with maximal absorption and the least number of complications underlying cause of their symptoms should be evaluated carefully and monitored more closely. (3) There continues to be controversy in the use of lactose containing instead of sucrose containing formulas in AGE. The available studies provide mixed results. In 1994, a meta-analysis was performed to evaluate lactose-containing diets in children with diarrhea. This study concluded that 80% of children with acute diarrhea and mild-to-moderate dehydration can tolerate full-strength lactose based formula safely, however other studies seemed to differ. (11) One study concluded that although both formulas were well tolerated, there was a 50% decrease in stool output and 40% shorter duration of diarrhea when using soy-based formula with sucrose instead of lactose. There was also an increase failure rate of lactose containing formulas in children with severe dehydration. (12) A second study suggests that the use of a low-lactose formula for re-feeding after gastroenteritis may have some advantages with respect to early weight gain and therefore, may be more important in the management of underweight children in whom prevention of further weight loss is important. (13) To further complicate the issue a third study that evaluated sucrose, lactose and polycose (small polymers of glucose) demonstrated recovery from AGE occurred within two weeks irrespective of carbohydrate ingested. The investigators concluded that most formula fed infants with mild acute gastroenteritis probably do not need to be routinely given a non-lactose containing formula. (14) These studies also suggest that rapid re-feeding as opposed to gradual re-feeding does not increase the risk of lactose malabsorption. The AAP currently recommends full strength milk/formula and that intestinal reduction of lactose is not necessary in most pediatric patients. (3) Managing children with AGE using regular age-appropriate diets is more cost effective than substituting more expensive formulas such as Alimentum or Nutramigen. Although human milk contains lactose, it is tolerated better than formula during diarrhea and therefore, breastfeeding should always be continued for oral rehydration of mild-to-moderate dehydration. Breast milk has a lower solute load and higher water content compared to formula and may actually decrease stool output. ( 13) Additionally, anti-infective properties present in breast milk including immunoglobulins (especially IgA), lactoferrin, and anti-adherent factors that may all contribute to the success of breast milk feeding in AGE. (15) Figure 1 presents an algorithm for feeding the child with AGE.
The `Brat Diet' (Bananas, Rice, Applesauce, Toast) also deserves attention. The previous studies that have been reviewed all used early feeding with a regular diet and showed no prolongation of symptoms. This Brat Diet is often well tolerated, but it does not provide adequate nutrition or caloric intake during AGE. It provides a large amount of carbohydrate, which may be poorly absorbed. It is also a low fat and protein diet that may contribute to watery stools by stimulating gut motility. (3) Probiotics Probiotics are receiving a great deal of attention in many fields. A probiotic is a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance. (16) Examples of probiotics in commercial products are yogurt and buttermilk. These products have long been advocated by Grandmothers for a variety of intestinal complaints, but more formal uses include prophylaxis for traveler's diarrhea, antibiotic-associated diarrhea, and the treatment of infectious diarrhea. They are also being studied in a variety of immune related conditions, and idiopathic inflammatory bowel disease. Probiotics have actually been used for decades to improve the symptoms of diarrhea. The most commonly used and studied probiotic organisms are the Lactobacillus species. There are multiple theories for their mechanism of action including the production of antimicrobial substances by various biotherapeutic agents, competition for nutrients, inhibition of adhesion of pathogens, modification of toxins or toxin receptors, and the trophic effects on the intestinal mucosa. (17) In the initial studies, these organisms were given in capsules. One study done using lactobacillus capsules found that the organism colonized the gastrointestinal tract and significantly shortened the duration of watery diarrhea associated with Rotavirus gastroenteritis. This study was difficult to interpret because of poor patient compliance with the large number of capsules that had to be ingested daily. (18) Two recent studies evaluated the addition of probiotic to ORS. A multi-center trial demonstrated a shortened duration of diarrhea and faster discharge from the hospital. (19) A second study also found that the addition of lactobacillus to ORT was effective at decreasing the duration of diarrhea. (20) These data suggest a role for probiotic therapy, however there still needs to be further studies to advocate the routine use of probiotics. The dose, organism, duration of therapy, and long-term effects need to be evaluated. Oral ImmunoglobulinsRecent studies evaluated the role of anti-viral therapy in Rotavirus induced AGE. The `lag property' of Rotavirus reproduction in the intestinal tract stimulated an interest in the use of oral immunoglobulins. A double blind, prospective, placebo-controlled study was conducted with the goal of determining effectiveness of oral immunoglobulins against rotavirus. The investigators concluded that oral administration of immunoglobulin is associated with faster recovery from AGE and should be given to children hospitalized with this illness. Additionally it is believed that the use of oral immunoglobulins should decrease iatrogenic spread of rotavirus in the hospital setting. It is predicted that treatment could reduce overall hospitalization by an average of two days. However, the cost would be two hundred dollars for a ten kilogram infant. The use of this therapy still requires further studies to reproduce the data and expand the studies to determine actual efficacy. (21) Conclusion Judicious use of ORS and early re-feeding are the major components of therapy for AGE. These are now well accepted, carefully studied, and are considered standard practice. Current research focuses on probiotic, immunoglobulins, and other anti-infectious agents to improve our ability to both heal and comfort our patients. In the future, we should expect to see further declines in the morbidity associated with diarrhea. REFERENCES
Jacksonville Medicine / October, 2000What's New
·
Northeast Florida Medicine Journal ·
Know Your Physician
· Legal
& Legislative
Duval County Medical Society
·
555 Bishopgate Lane
·
Jacksonville, FL 32204 |
The AAP currently recommends that children with AGE who require rehydration should be fed
an age appropriate diet as soon as they have been rehydrated. These recommendations apply
to previously healthy, well-nourished children from 1 month to 5 years of age. Infants
less than one month of age who are more likely to develop intractable diarrhea or have a
more serious
investigation. Table 1 provides data on the components of generally available solutions. 