Most episodes of gastroenteritis are caused by self limited viral infections. Depending on exposure to large numbers of people, four to five episodes/year for this first 2 to 5 years is not unusual. There is often fever at the onset along with variable degrees of respiratory symptoms. When vomiting is present, it tends to occur primarily in the first day or two of the illness; it may be as little as once or twice a day or as severe as literally vomiting each and every time fluid are offered. When diarrhea is present, it may be very infrequent and may be as often as a stool an hour! The mechanism underlying the diarrhea is temporary damage done to the fingerlike projections (villi) that line the small intestine and on the surface of which are the enzyme containing cells that are essential for the normal digestion and absorption of the normal diet. When these villi are damaged, a significant proportion of the child’s fluid and caloric intake cannot be absorbed and flows down to the colon where bacteria metabolize the nutrients that normally do not reach this area resulting in a highly acidic stool and cramping due to gas formation. On average, it takes 5-7 days for these villi and their surface enzyme containing cells to regenerate themselves and for the normal absorption of fluid and nutrients to be restored. Just as for respiratory illnesses the children are considered non-contagious when they are free of fever for 24 hours and having diminished symptoms, although the actual communicability may extend another seven to ten days. Thus the main defense against contagion is frequent hand washing by all caretakers.
Vomiting and diarrhea is treated by replacing the fluid lost with a balanced fluid and electrolyte solution called PEDIALYTE, INFALYTE, RICELYTE available OTC in groceries and pharmacies. Extensive research has shown that these fluids contain an ideal proportion of glucose and electrolytes that maximize absorption of fluid and replace lost electrolytes in the presence of ongoing losses. There is no other fluid that is as effective in preventing dehydration; Gatorade, dilute soft drinks, tea, Kool-aid, etc. should not be used for this purpose in young infants with significant fluid losses with gastroenteritis. While the children will sometimes take these substitutes more readily, they may ironically cause increased fluid losses as their composition actually promotes fluid loss across the injured intestinal surface. When vomiting is severe, fluids should be given in very small amounts at frequent intervals and gradually increased in volume as tolerated. Once the vomiting has abated, fluids can be advanced to match stool losses. As soon as the vomiting has passed, reintroduction of breast milk and/or formula can be attempted along with bland solid foods (rice cereal, bananas, apple sauce) in children who were taking them prior to the illness. If there is a prompt recurrence of vomiting as the diet is advanced, Pedialyte should be reused for a few feedings and then another attempt at breast milk or formula. If the vomiting recurs at each attempt at diet advancement, the child may be temporarily lactose intolerant and may benefit from a trial of a sucrose containing formula such as Isomil-DF. The diarrhea will usually subside over a 5-7 day period. The general trend is for a gradually diminishing number and size of stools, while the child may have the occasional blowout from day to day! Other treatments for viral gastroenteritis such as Kaopectate are of very doubtful efficacy. Immodium AD is not an effective anti-diarrheal, but may provide some relief of cramping in the older child. Pepto-bismol is also of unproven benefit as an anti-diarrheal despite its longstanding advertisements and has the additional hazard of containing bismuth subsalicylate, an aspirin related compound that may be capable of causing Reye’s Syndrome (liver failure and cerebral edema-often fatal). It should not be used.
Signs and symptoms that may signify the need for and office visit include: significant fever beyond 48 hours; repetitive vomiting beyond 24 hours, bile stained (dark green to black) or bloody vomitus; severe and persistent cramping; bloody stools; fluid losses that appear to exceed intake; signs of dehydration (lethargy, less than 3-4 wet diapers/day, sunken fontanel, dry eyes-lips-tongue, mottled skin color, temperature below 97 degrees F.