Page 724 - Problem-Based Feline Medicine

716 PART 9 CAT WITH SIGNS OF GASTROINTESTINAL TRACT DISEASE

Clinical signs may also facilitate diagnosis via fine-needle aspiration
or biopsy.
Weight loss and anorexia are the earliest and most
common clinical signs. Ultimately, histopathologic examination of the tissue
is necessary for a definitive diagnosis.
Lethargy or depression are also common.
In cats with obstructive or mass lesions, lesions
Diarrhea is most common with infiltrative neo-
unreachable by the endoscope, or when ultrasound-
plasms, such as alimentary lymphoma, which is the
guided fine-needle aspirates are non-diagnostic, surgi-
most common neoplasm in the feline small intestine.
cally obtained biopsies and resection are the best
Vomiting is a common presenting complaint and approach.
may be associated with hematemesis.
In the USA there is no breed predilection for lym-
phoma, but Siamese cats appear to be predisposed to Differential diagnosis
adenocarcinoma.
Alimentary lymphoma is easily (and often) mis-
Signs typically occur in older cats, however, alimen- taken, especially in the early stages of disease, for
tary lymphoma occurs in cats of all ages. lymphoplasmacytic enteritis (inflammatory bowel
disease).
Intestinal forms of lymphoma are usually found in
FeLV-negative cats, however, the multicentric form of Many other severe GI or systemic diseases may
lymphoma can involve the GI tract and is often asso- resemble intestinal neoplasia, including hyperthy-
ciated with FeLV-positive antigenemia where FeLV is roidism, chronic renal failure or liver disease, pancre-
frequent in the feline population. atitis, severe food intolerance or sensitivity, and severe
forms of infectious enteritis. Differentiation of these
Both adenocarcinoma and mast cell tumors of the GI
diseases is based on blood testing, exploratory
tract are often associated more with vomiting and weight
laparotomy and intestinal biopsy.
loss due to their mass-like, obstructive behavior.
In cats with mass-like or obstructive lesions, other
diseases to consider are intussusception or foreign
Diagnosis bodies, FIP or fungal granulomas, and focal abscesses.
Differentiation often requires exploratory laparotomy
Palpation of the abdomen may reveal a mass or
or biopsy.
thickened intestinal loops.
Hematology and serum chemistry profiles are usu-
ally non-specific, but help to rule out other causes of Treatment
vomiting. The most frequent hematologic abnormal-
ity is anemia of chronic disease (normocytic, nor- For adenocarcinoma, mast cell tumors and other
mochromic), but blood loss anemia is also observed. tumors that tend to occur as solitary mass lesions,
The abnormalities found in the chemistry profile surgical removal via intestinal resection is the pri-
depend on the extent of the disease and severity of mary approach. Biopsies should be obtained of
vomiting, and are non-specific as well. liver, regional lymph nodes and mesenteric tissues
to determine if metastasis has occurred and its
The most helpful diagnostic procedures are imaging
extent.
techniques: radiography, ultrasonography or possibly
endoscopy. There are no specific radiographic features of Chemotherapy has not been proven effective for
neoplasia, since it may be infiltrative or obstructive in adenocarcinoma or intestinal mast cell tumors.
nature. Ultrasound may be more helpful in identification
Lymphoma of the alimentary tract is generally an
of thickened loops of bowel or mass lesions.
infiltrative neoplasm and chemotherapy using com-
Depending on the location and size of the mass, ultra- bination protocols (COAP, etc.) are the treatments of
sonography will allow visualization of the lesion, and choice. See main reference on page 676 for details.