Page 502 - Small Animal Internal Medicine, 6th Edition

474 PART III Digestive System Disorders

CHAPTER 31
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Disorders of the

Intestinal Tract

ACUTE DIARRHEA abdominal pain or masses are detected or if obstruction or
foreign body are suspected.
ACUTE ENTERITIS
Treatment
Etiology Symptomatic therapy usually suffices. The cause is usually
Acute enteritis is most commonly caused by infectious unknown or is a virus for which there is no specific therapy.
agents, poor diet, abrupt dietary changes, inappropriate The goal of symptomatic therapy is reestablishment of fluid,
foods, additives (e.g., chemicals), and/or parasites. Recent electrolyte, and acid-base homeostasis. Animals with severe
boarding at a kennel, being a scavenger, or having a recent dehydration (i.e., ≥8%-10% as determined by sunken eyes,
diet change are risk factors for developing acute diarrhea. fast weak pulse, and marked depression, or a history of sig-
Except for parvovirus, parasites, and obvious dietary indis- nificant fluid loss coupled with inadequate fluid intake)
cretions, the cause is rarely diagnosed, because most affected should receive intravenous (IV) fluids, whereas fluids admin-
animals spontaneously improve with or without supportive istered orally or subcutaneously usually suffice for patients
therapy. less severely dehydrated. Potassium supplementation is
usually indicated, but bicarbonate is rarely needed. Oral
Clinical Features rehydration sometimes allows home management of animals,
Diarrhea of unknown cause is common, especially in puppies especially when litters of young animals are affected. (See the
and kittens. Signs consist of diarrhea with or without vomit- discussion on fluid, electrolyte, and acid-base therapy in
ing, dehydration, fever, anorexia, depression, crying, and/or Chapter 28 for details.)
abdominal pain. Very young animals may become hypother- Antidiarrheals are seldom necessary except when exces-
mic, hypoglycemic, and stuporous. sive fecal losses make maintenance of fluid and electrolyte
balance difficult. Opiates are usually the most effective antid-
Diagnosis iarrheals. Bismuth subsalicylate (see Table 28.6) is useful in
History and physical and fecal examinations are used to iden- stopping diarrhea in dogs with mild to moderate enteritis.
tify possible causes. Fecal flotation (preferably a centrifugal However, absorption of the salicylate may cause nephrotox-
flotation using zinc sulfate flotation solution) and direct fecal icity in some animals (especially when combined with other
examinations are always indicated because parasites may potentially nephrotoxic drugs), and many dogs dislike the
worsen the problem even if they are not the main cause. The taste. Cats rarely need these medications. (See the discussion
need for other diagnostic procedures depends on severity of on drugs that prolong intestinal transit time in Chapter 28.)
the illness and the risk of contagion. Clinically mild enteritis If antidiarrheals are needed for more than 2 to 5 days, the
is usually treated symptomatically, with few diagnostic tests animal should be carefully reassessed. Probiotics typically
being performed. If the animal is febrile, has hemorrhagic shorten the duration of acute diarrhea.
stools, is part of an outbreak of enteritis, or is particularly Severe intestinal inflammation often causes vomiting that
ill, then additional tests (e.g., complete blood count [CBC] is difficult to control. Central-acting antiemetics (e.g.,
to identify neutropenia, fecal enzyme-linked immunosor- maropitant or ondansetron; see Table 28.3) are more likely
bent assay [ELISA] for canine parvovirus, serologic analysis to be effective than peripheral-acting drugs.
for feline leukemia virus [FeLV] and feline immunodefi- Although food is typically withheld from animals with
ciency virus [FIV], blood glucose to identify hypoglycemia, severe enteritis to “rest” the intestinal tract, such starvation
and serum electrolytes to detect hypokalemia) are reason- may be counterproductive. Administering even small
able. Abdominal imaging should be evaluated if obvious amounts of food to the intestines helps them recover sooner

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