Page 710 - Problem-Based Feline Medicine

702 PART 9 CAT WITH SIGNS OF GASTROINTESTINAL TRACT DISEASE

secondary to systemic illness (peritonitis, septicemia), Pathogenesis
organ failure (hepatic, renal or pancreatic disease) or
Mild, acute small bowel diarrhea is a common pre-
other miscellaneous causes such as hyperthyroidism.
senting complaint, and may be caused by a variety of
A careful history and physical examination will deter- self-limiting disturbances, including dietary, parasitic,
mine whether the problem is likely related to the GI infectious or toxic agents.
tract or a systemic problem.
Small bowel diarrhea can be caused by osmotic
In otherwise healthy cats with acute diarrhea that is (increased unabsorbed substances present in the lumen,
likely due to dietary indiscretion, mild infectious enteri- such as occurs in overeating or malabsorption), secre-
tis or exposure to a self-limiting toxin, a minimal diag- tory (increased secretion of ions and water into the
nostic approach is needed. lumen, which is mediated by second messengers such as
cAMP or cGMP and often stimulated by bacterial or
In cats that are dehydrated, clinically depressed,
viral agents), increased permeability (increased intes-
anorectic or vomiting, a more aggressive approach that
tinal permeability occurs from diseases that cause
includes a hemogram, chemistry profile, fecal analy-
increased inflammation, erosion, ulceration or necrosis),
sis, and radiographs or ultrasound is indicated.
and altered intestinal motility (increased or decreased
WHAT? intestinal motility can result in diarrhea, especially
when it affects segmentation contractions in the colon).
The most common causes of mild, self-limiting small
Cats with self-limiting gastroenteritis require minimal
bowel diarrhea include food intolerance or dietary
diagnostic testing and will respond to symptomatic
indiscretion, and some infectious or parasitic agents.
treatment.
Cats with small bowel diarrhea of a more serious nature
Certain strains of E. coli may behave as gastrointestinal
often have systemic illness/organ failure (e.g. hepatitis,
pathogens. Very little is known about diarrheagenic
renal failure, or pancreatic disease such as pancreatitis), or
E. coli in cats and further epidemiological investigations
severe intestinal disease such as neoplasia or inflamma-
on this subject are needed. One recent study showed no
tory bowel disease, which must be carefully evaluated.
difference in the strains of E. coli isolated from a group
Diagnosis is based upon history and physical examination of cats with diarrhea and a control group of cats that did
findings, radiography, hematology and serum chemistry not have diarrhea.
profiles, serology if indicated for FeLV/FIV, serum TLI,
fecal analysis, fecal cytology or alpha-1 protease inhibitor
Clinical signs
testing, serum cobalamin/folate assays and histopathology.
Acute onset of vomiting, diarrhea, anorexia or
DISEASES CAUSING SIGNS OF lethargy in an otherwise healthy cat.
ACUTE SMALL BOWEL DIARRHEA
Dehydration may occur if the signs are severe.
(<3 WEEKS DURATION)
Rarely associated with hematemesis, hematochezia or
melena.
ACUTE GASTROENTERITIS***

Classical signs Diagnosis
● Vomiting, anorexia or reduced appetite are Acute idiopathic gastroenteritis is a pathological
common. description and not a diagnosis. One of the many eti-
● Acute gastroenteritis is more common in ologies listed in this chapter is the likely cause.
young cats or kittens, but can occur in any However in cats that are otherwise healthy, but have
age, breed or sex. mild signs of gastroenteritis and no clinical evidence of
● Mild to severe small bowel diarrhea may dehydration, an extensive diagnostic work-up is rarely
also be observed. indicated or performed so the cause of the signs
remains unknown.