Page 1060 - Small Animal Clinical Nutrition 5th Edition

1102 Small Animal Clinical Nutrition

the source of the patient’s diarrhea. a,b Often, it is possible to may be identified. Acid-base derangements may occur with
VetBooks.ir elicit a history of food change, indiscretion, feeding table foods diarrhea, but are more common with small bowel disease.
Hypoproteinemia and hypoalbuminemia may be recognized in
over a holiday or access to garbage, carrion or abrasive materi-
severe cases of PLE. Dehydrated patients may have prerenal
als, such as bones.
Other husbandry issues are also important; for example, azotemia.
records of anthelmintic treatments should be scrutinized. The Fecal examinations are very important in the evaluation of
likelihood that an infectious organism is involved is increased if patients with chronic large bowel diarrhea. Multiple fecal par-
other animals or people in the household are similarly affected. asite examinations using concentration techniques are neces-
Dogs and cats with acute colitis may act depressed and be sary to rule out parasitism and infection with organisms such as
dehydrated and may exhibit pain on abdominal palpation. Giardia and T. foetus.
Patients should be carefully evaluated for evidence of septic Endoscopic abnormalities in chronic colitis may include
shock. Those patients with systemic signs of illness (i.e., fever mucosal granularity, hyperemia, increased friability and inabil-
and congested mucous membranes) in addition to gastroin- ity to visualize colonic submucosal blood vessels (Jergens et al,
testinal (GI) signs should be treated more aggressively. 1992). Multiple biopsy specimens should be collected from
Physical examination findings vary in dogs and cats with multiple bowel segments. Even if these areas appear normal
chronic colitis. Many patients have no abnormalities. Rarely, endoscopically, histologic changes may still be present (Jergens
dogs and cats with colitis present with weight loss and poor et al, 1992; Roth et al, 1990; Marks and LaFlamme, 1998).
body condition. In such cases, serious infiltrative colonic disor- The definitive diagnosis of IBD is based on histopathologic
ders (e.g., histoplasmosis, neoplasia, histiocytic colitis or large examination of endoscopic or surgical biopsy specimens
intestinal disease complicated by small intestinal disease) (Wilcock, 1992).
should be suspected.
Occasionally, thickened loops of bowel may be palpated, Risk Factors
especially in cats. Segmental thickening of bowel is consistent The risk factors for acute colitis include age, breed, immune
with eosinophilic gastroenterocolitis in cats and granulomatous status and environment. Puppies and kittens are more suscep-
enteritis in dogs (Moore, 1983; Lecoindre et al, 2007). This tible to a variety of infectious pathogens including parasites
finding should also be distinguished from intussusceptions, for- (Gookin et al, 2004), viruses and bacteria. Likewise, immuno-
eign bodies, histoplasmosis and neoplastic lesions. compromised dogs and cats are at risk for contracting viral and
bacterial enteritides. Hospitalization and administration of
Laboratory and Other Clinical Information cancer chemotherapeutic drugs are associated with nosocomial
Because there are many potential causes of acute colitis, achiev- infection with Clostridium (Twedt, 1992) and Campylobacter
ing a definitive diagnosis can be difficult. In acute cases, it is (Davenport, 1989) spp.
most important to determine whether the patient’s condition is Environment also plays an important role in exposure to
self-limiting or potentially life-threatening. This determina- pathogens. Dogs and cats kept in unsanitary or overcrowded
tion, based on historical and physical findings is critical. Some conditions are much more likely to develop infectious
factors suggest a potentially life-threatening condition (Table enteropathies. In addition, pets kept in poorly controlled envi-
56-1). Cases of a serious nature should be pursued aggressively ronments have a higher risk for exposure to high-fat table foods,
with diagnostics (i.e., hematology, serum biochemistry profiles, garbage and toxins. Dogs in particular eat indiscriminately.
urinalyses and fecal examinations for parasites and other infec- Consumption of rotten garbage, decomposing carrion and abra-
tious pathogens such as Giardia and Tritrichomonas foetus) sive materials (e.g., hair, bones, rocks, plastic, aluminum foil,
(Leib, 2002; Washabau, 2004a). An abundance of inflammato- etc.) can result in severe colitis.Poor husbandry practices includ-
ry cells in a fecal smear is an important finding and justifies a ing inadequate parasite control and overcrowding also put pets
fecal culture. Self-limiting cases are usually approached more at risk for acute colitis. Feeding raw foods may predispose dogs
conservatively. Diagnostics are often limited to assessing hydra- and cats to infectious enteropathies (Chapter 11).
tion status (i.e., packed cell volume, total protein concentration There does not appear to be an age or gender predisposition
and body weight) and a thorough examination of feces for par- for any of the forms of IBD. Certain breeds appear to be at risk
asites and bacterial pathogens (e.g., spores of Clostridium spp. or for specific colonic disorders (Table 61-3). For example, the
clostridial enterotoxins). boxer breed is linked to histiocytic colitis (van Kruiningen,
Laboratory findings in patients with chronic colitis are often 1967). Other breeds at risk for chronic inflammatory colon-
nonspecific. Hematologic findings are variable and may in- opathies include German shepherd dogs and French bulldogs
clude blood loss anemia, anemia of chronic disease, (Guilford, 1996).
eosinophilia and lymphopenia. Serum biochemistry profiles
and urinalyses should be performed on samples from patients Etiopathogenesis
with chronic diarrhea to assess the systemic affect of the GI Chapter 55 describes four mechanisms of diarrhea. In acute
disorder and to rule out concurrent disease. Decreased choles- colitis, diarrhea may occur as a result of altered gut permeabili-
terol values may be seen in patients with colitis. Electrolyte ty or osmotic mechanisms. Many of the bacterial pathogens
abnormalities, including hypokalemia and hypochloremia, elaborate enterotoxins that serve as potent secretogogues.