Page 491 - Small Animal Internal Medicine, 6th Edition

CHAPTER 30 Disorders of the Stomach 463

disseminated intravascular coagulation (DIC), and/or renal results in one sample that is randomly taken without knowl-
injury. In severe cases, the animal may be moribund by the edge of how the gastric mucosa appears. Gastric biopsy
VetBooks.ir time of presentation. should always be performed regardless of the gross mucosal
appearance. However, enteritis is far more common than
Diagnosis
important than gastric biopsies. Gastric lymphoma can be
These animals are typically hemoconcentrated (i.e., packed gastritis, which is why duodenal biopsies are usually more
cell volume [PCV] ≥ 55%) with normal plasma total protein surrounded by lymphocytic inflammation, and obtaining
concentrations. Acute onset of typical clinical signs plus inappropriately superficial tissue specimens can produce an
marked hemoconcentration allows a presumptive diagnosis. incorrect diagnosis of inflammatory disease. Endoscopes
Thrombocytopenia and renal or prerenal azotemia may be with a 2.8-mm biopsy channel make it easier to avoid inap-
seen in severely affected animals. propriately superficial samples. Accurate histopathologic
interpretation of alimentary tissue can be difficult; the clini-
Treatment cian should not hesitate to request a second opinion if the
Aggressive fluid therapy is initiated to treat or prevent shock, histologic diagnosis does not fit the patient or the response
DIC secondary to hypoperfusion, and renal failure second- (or lack thereof) to therapy. If Ollulanus tricuspis is sus-
ary to hypovolemia. Parenteral antibiotics (e.g., ampicillin) pected, vomitus or gastric washings should be examined for
are often used because of the fear that intestinal bacteria are the parasites, but they might also be found in gastric biopsy
proliferating, but their value is doubtful and they are no specimens. Physaloptera can be seen endoscopically, but they
longer recommended. If the patient becomes severely hypo- can be very small if they are immature.
albuminemic, synthetic colloids or plasma may be required.
Treatment
Prognosis Lymphocytic-plasmacytic gastritis sometimes responds to
The prognosis is good for most animals that are presented in dietary therapy (e.g., low-fat, low-fiber, elimination diets)
a timely fashion. Inadequately treated animals may die due alone (see pp. 434-435). If such therapy is inadequate,
to circulatory collapse, DIC, and/or renal failure. glucocorticoids (e.g., prednisolone, 2.2 mg/kg/day) can be
used concurrently. Even if glucocorticoids are required,
CHRONIC GASTRITIS appropriate dietary therapy may allow one to administer
a substantially decreased dose, thus avoiding glucocorti-
Etiology coid adverse effects. If glucocorticoid therapy is necessary,
There are several types of chronic gastritis (e.g., lymphocytic/ the dose should be gradually decreased to find the lowest
plasmacytic, eosinophilic, granulomatous, atrophic). Lym- effective dose. However, the dose should not be tapered too
phocytic-plasmacytic gastritis might be an immune and/or quickly after obtaining a clinical response or the clinical
inflammatory reaction to a variety of antigens. Helicobacter signs may return and be more difficult to control than they
spp. and Physaloptera rara may produce such a reaction in were initially. In rare cases, azathioprine or similar drugs
some patients (especially cats and dogs, respectively). Eosin- will be necessary (see Chapter 28). Proton pump inhibitors
ophilic gastritis may represent an allergic reaction, probably are sometimes beneficial. Ulceration should be treated as
to food antigens. Atrophic gastritis may be the result of discussed on pages 470-471.
chronic gastric inflammatory disease and/or immune mech- Canine eosinophilic gastritis usually responds well to a
anisms. Ollulanus tricuspis may cause granulomatous gastri- strict elimination diet. If dietary therapy alone fails, gluco-
tis in cats. corticoid therapy (e.g., prednisolone, 1.1-2.2 mg/kg/day) in
conjunction with diet is usually effective. Feline hypereo-
Clinical Features sinophilic syndrome responds poorly to most treatments.
Chronic gastritis appears to be more common in cats than Atrophic gastritis and granulomatous gastritis tend to be
in dogs. It is not clearly associated with chronic enteritis. difficult to treat. Diets low in fat and fiber (e.g., one part
Hyporexia and vomiting are the most common signs in cottage cheese and two parts potato) may help control signs.
affected dogs and cats. Frequency of vomiting varies from Atrophic gastritis might respond to antiinflammatory,
once weekly to many times a day. Some animals only dem- antacid, and/or prokinetic therapy; the latter is designed to
onstrate hyporexia, ostensibly because of low-grade nausea. keep the stomach empty, especially at night. Idiopathic gran-
ulomatous gastritis is uncommon in dogs and cats and does
Diagnosis not respond well to dietary or glucocorticoid therapy.
Clinical pathologic findings are rarely helpful; eosinophilic
gastritis inconsistently causes peripheral eosinophilia. Ultra- Prognosis
sound sometimes documents mucosal thickening. Diagnosis The prognosis for canine and feline lymphocytic-plasmacytic
requires gastric mucosal biopsy. Because gastritis may be gastritis is often good with appropriate therapy. Lymphoma
generalized or localized, endoscopy is the best way of obtain- has been suggested to develop in cats with preexisting lym-
ing tissue samples. Endoscopy allows multiple biopsies over phocytic gastritis; however, it is impossible to know whether
the entire mucosal surface, whereas surgical biopsy typically the original diagnosis of lymphocytic gastritis was incorrect,