Gastrointestinal problems in pediatric patients require careful assessment

Gastrointestinal problems in puppies and kittens after birth to adulthood are extremely common. In the last 10 years, there actually have been no new or unique gastrointestinal problems noted in puppies and kittens. However, the practical principles of diagnosing and managing common gastrointestinal problems are still warranted.

Gastric disorders

Vomiting is the primary sign of gastric disorders and as an event first appears in puppies and kittens with a full stomach at 3 days and 10 days of age, respectively. The vomiting is usually preceded by a short period of nausea with licking, hypersalivation or multiple attempts at swallowing. This is followed by retching or several forceful, simultaneous diaphragmatic and abdominal contractions and, with the head lowered, expulsion of gastric contents. Observation of the amount, color and consistency of vomitus is useful for obtaining insight into the origin of a gastric disorder and the degree of mucosal damage. If the vomitus consists of food, the degree of digestion indicates the length of time food has remained in the stomach. Vomitus can contain varying amounts of mucus and fluid from gastric and swallowed salivary secretions. Yellow-stained or green-stained vomitus indicates intestinal reflux of bile into the stomach. Vomitus containing feces usually indicates intestinal stasis or possibly intestinal obstruction. Fresh blood from gastric bleeding may be present as small red flecks or as large blood clots. Blood that has been retained in the stomach soon becomes partially digested and has a brown "coffee grounds" appearance. The presence of blood in vomitus usually signifies a more serious gastric disorder. Other signs associated with gastric disorders may include nausea, belching, inappetence, polydipsia and pica. Black tarry stools are seen with upper gastrointestinal bleeding and may imply gastric mucosal damage.

Gastritis can be associated with a multitude of causes but more commonly results from dietary indiscretions, infectious diseases and possibly endoparasites. Ingestion of foreign material such as bones, pins, needles, plastic objects, food wrappings, rocks and small toys mechanically irritates the gastric mucosa and thereby causes gastritis. The incidence of ingested foreign material is much higher in young dogs and cats, possibly owing to their developmental chewing habits and curious natures. Trichobezoars (hairballs) are frequently seen in the vomitus of long-haired cats and some dogs. Many drugs (antimicrobial agents, nonsteroidal anti-inflammatory drugs, anthelmintics and corticosteroids) and chemicals (heavy metals, cleaning agents, fertilizers and herbicides) may also contribute to gastritis in the young animal. Bacterial-induced gastritis is extremely uncommon because the acidic gastric lumen does not favor the growth and colonization of bacteria. Helicobacter spp. are commonly present but non-contributory to gastric disease. Viruses, most commonly canine herpesvirus and parvoviruses, may cause gastric lesions and vomiting as a part of a more extensive disease condition. Endoparasites seldom produce gastric lesions or signs. Physaloptera spp., Ollulanus tricuspis (cats), ascarids, and, occasionally, tapeworms are endoparasites that may be associated with gastric irritation and vomiting. Other conditions, including renal failure, liver disease, neurologic disease, shock, sepsis and possibly altered behavior, may also play a role in the cause of gastritis in the young dog and cat.

Management of vomiting

Symptomatic treatment of most cases of gastritis and vomiting begins without extensive diagnostic procedures. Most young animals show improvement within 12-24 hours following little or no therapy and usually are treated on an outpatient basis. Those young animals with persistent vomiting; evidence of dehydration, abdominal pain, organomegaly or palpable abdominal mass; or failure to respond to previous symptomatic treatment require further medical and laboratory evaluation. The general principles in the treatment of gastric disorders include removing the inciting cause; providing proper conditions to promote mucosal repair; correcting fluid, electrolyte and acid-base abnormalities; and alleviating secondary complications of gastritis, such as abdominal pain and diarrhea.

Dietary restriction is the initial management for gastritis. A young animal with gastritis should be withheld food for 24-48 hours and water for 12-24 hours. If no vomiting occurs during this period of management, over the next two to five days the animal is gradually returned to full feed and water. Water is offered initially in small, frequent amounts or provided in ice cubes, enough to keep the mouth moist and to supply a modest fluid replacement. Until vomiting is well controlled, feed small amounts frequently (three to six times daily) of a highly digestible, low-fiber diet. One can expect most cases of vomiting in young dogs and cats will respond to just dietary and water intake management.

Table 1: Antiemetics and Dosages

Administration of parenteral fluids, antiemetics (Table 1, p. 24), and secretory H2-receptor antagonists (Table 2, p. 25) drugs may be given to control refractory vomiting in puppies and kittens and when a gastric foreign object has been ruled out. antiemetic drugs inhibit vomiting but do little for primary treatment of gastritis. Anticholinergic drugs reduce gastric motility and smooth muscle spasms. Overuse of the anticholinergic drugs can cause gastric atony and a pharmacologic gastric outflow obstruction, resulting in further vomiting. Oral protectants and antimicrobial agents are usually not indicated in the treatment of gastritis. Severe gastric hemorrhage should be treated as an emergency. Whole blood and parenteral fluids should be given to replace blood and fluid lost. Attempts at controlling bleeding are generally made with the use of gastric lavages with ice water or surgical gastrectomy.

Gastric retention problems

Gastric retention and paresis are most often associated with pyloric dysfunction, motility disturbances of the stomach, or both. Pyloric dysfunction in the young dog or cat usually results from congenital pyloric stenosis or from an intraluminal foreign object obstructing the gastric outflow area. Traumatic injury and inflammatory bowel disease can reduce motility throughout the gastrointestinal tract, resulting in the retention of gastric contents and recurrent episodes of mild bloating. Management should then be directed toward control of the underlying condition and possibly stimulating gastric motility.

Table 2: Summary of Therapeutic Products for Management of Gastrointestinal Disorders

Intestinal disorders

Diarrhea is the primary sign of intestinal disorders and often occurs secondary to many non-intestinal diseases. Diarrhea of young dogs and cats typically is of abrupt onset and has a short course that ranges from transient and self-limiting to fulminating and explosive. With the aid of history, physical examination, and stool characteristics (frequency, volume, consistency, color, odor, and composition) diarrhea can be localized to the small intestine, large intestine, or both (Table 3), and a search for the cause and treatment can be undertaken.

Diarrheal disorders are associated with many causes but more commonly results from dietary indiscretions, infectious diseases, and endoparasitism. Dietary causes may include intestinal overload from overeating; ingestion of rancid or spoiled foodstuffs from scavenging of decomposing garbage or carrion; ingestion of indigestible and abrasive foreign material, intolerance of lactose ingested as milk; and intolerance of miscellaneous types of food, such as fatty or spicy food. Food allergies that are expressed as signs of inflammatory bowel disease may first begin to contribute to enteropathic signs at 3 to 4 months of age. Ingesting foreign objects occurrence is much higher in young dogs and cats, probably because of their developmental chewing habits and curious natures. Trichobezoars are frequently encountered in the diarrheic stools of long-haired cats and some dogs. Many drugs (corticosteroids, nonsteroidal anti-inflammatory drugs, antimicrobial agents, and anthelmintics) and chemicals (heavy metals, cleaning agents, fertilizers, and herbicides) may cause diarrheal problems. Many ingested plants and plant toxins may cause diarrhea and an associated enterocolitis.

Table 3: Differentiation of Small Intestinal Diarrhea from Large Intestinal Diarrhea

Many infectious agents are often associated with varying degrees of enterocolitis. Bacteria (Salmonella spp., Escherichia coli, Campylobacter spp., Yersinia enterocolitica, Bacillus piliformis, and Clostridium perfringens) reside in, and may contribute to severe mucosal damage in, the small and/or large intestine. Canine parvovirus-2 and feline parvovirus-1 infections are still important causes of enterocolitis in young dogs and cats, respectively. In refractory diarrheal problems, feline leukemia virus, feline immunodeficiency virus, and feline infectious peritonitis virus should also be considered in the diagnosis.

Endoparasites typically do not produce intestinal lesions but contribute importantly to generalized unthriftiness, diarrhea and weight loss or failure to gain adequate body weight. The younger the animal, the more frequent are endoparasites present and the more severe the consequences of endoparasitism. Endoparasitism often complicates other existing intestinal disorders such as virus-induced or bacterial-induced enterocolitis. Other disorders, including renal failure, liver disease, neurologic disease, shock, sepsis, hypoadrenocorticism, stress, and even altered behavior, may play a prominent role in the cause of enterocolitis.

Managing diarrheal disorders

Symptomatic treatment is given initially for most cases of enterocolitis and diarrhea without extensive diagnostic procedures. Most young animals with enterocolitis show improvement within 24-48 hours with little or no therapy and usually are treated on an outpatient basis. The basic principles in the treatment of enterocolitis include removing the inciting cause; providing proper conditions to promote mucosal repair; correcting fluid, electrolyte, and acid-base abnormalities; and alleviating secondary complications of enterocolitis, such as vomiting, abdominal pain, and infection.

Dietary restriction is the initial step in management of enterocolitis. Animals with severe intestinal disturbances should be deprived of food for 24-48 hours. Water may be offered in small amounts during the first 24 hours. However, if the animal is vomiting, water should be restricted. Restriction of food and possibly water allows for restoration of mucosal integrity and a more rapid return of gastrointestinal function. In most cases, fasting reduces or eliminates diarrhea by removing the osmotic or irritating effects of undigested or unabsorbed nutrients. If no diarrhea has occurred during the 24- to 48-hour fast, small amounts of a highly digestible, low-fiber, moderately low-fat diet are fed three to six times daily. With the commercial diets formulated for gastrointestinal disease, begin feeding the animal with one third the amount needed to meet normal maintenance caloric needs. Over the next several days, gradually increase the amount of food to meet the animal's needs in order to maintain body weight.

The use of narcotic analgesics as anti-motility drugs is warranted in the treatment of some diarrheas (Table 2, p. 25). The rationale behind their use is based on their direct action on the smooth muscle of the small intestine and colon, causing increasing tone and segmentation. The narcotic analgesics, such as diphenoxylate hydrochloride and loperamide hydrochloride, are the preferred motility modifiers to use in the symptomatic treatment of diarrhea. Because of the frequent occurrence of endoparasites as the primary or secondary cause of enterocolitis in the young dog or cat, routine administration of an appropriate anti-parasitic drug is also recommended. The use of antimicrobial agents is warranted only when there is evidence of inflammation in the gastrointestinal tract (numerous inflammatory cells in the feces), damaged intestinal mucosa (blood in the stool), a systemic inflammatory reaction (fever and leukocytosis), and/or abnormal fecal culture results.

Suggested Reading

• Burrows CF, Merritt AM: Assessment of gastrointestinal function. In: Anderson NV (ed): Veterinary Gastroenterology, 2nd edition. Philadelphia, Lea & Febiger, 1992, p 16.
• Hoskins JD: The digestive system. In Hoskins JD (ed): Veterinary Pediatrics: Dogs and Cats from Birth to Six Months, Third Edition. Philadelphia, WB Saunders Co, 2001, p 147.
• Jergens AL: Inflammatory bowel disease. Vet Clin North Am Small Anim Pract 29:501, 1999.