Page 526 - Small Animal Internal Medicine, 6th Edition

498 PART III Digestive System Disorders

Clinical Features Diagnosis
Diarrhea and weight loss (i.e., small intestinal dysfunction) Vomiting of gastric contents (which can occur with gastric
VetBooks.ir are the most common signs. Hyporexia is also a frequent outflow obstruction or intestinal obstruction) classically
produces a hypokalemic-hypochloremic metabolic alkalosis
problem.
Diagnosis and paradoxical aciduria, whereas vomiting of intestinal
contents classically causes varying degrees of hypokalemia
Leukocytosis, hypoalbuminemia, and hypocholesterolemia often with some degree of lactic acidosis from poor perfu-
may occur. Typical histopathologic findings are moderate to sion. However, these changes are not reliable for diagnosis.
severe lymphocytic/plasmacytic infiltrates in the duodenum Hence, serum electrolyte and acid-base determinations are
and ileum. Architectural changes are also expected (i.e., important when planning therapy.
crypt distention, blunt villi, lymphangiectasia). Abdominal palpation, plain abdominal radiographs, or
ultrasonographic imaging can be diagnostic if they reveal a
Treatment foreign object, mass, or obvious obstructive ileus (see Fig.
Optimal therapy is uncertain. Therapy for IBD (i.e., elimina- 27.5, A). Abdominal ultrasonography performed by a com-
tion diets, antimicrobial drugs, and antiinflammatory/ petent clinician tends to be the most sensitive technique
immunosuppressive drugs) is currently recommended. (unless intestines are filled with gas) because it can reveal
dilated or thickened intestinal loops not obvious on radio-
Prognosis graphs. Furthermore, ultrasound may allow aspirate cytol-
Most affected dogs die within 3 months of diagnosis. ogy of masses and diagnosis of some diseases (e.g.,
lymphoma) without surgery. If it is difficult to distinguish
IDIOPATHIC GRANULOMATOUS obstruction from physiologic ileus, abdominal contrast
ENTERITIS AND/OR COLITIS radiographs may be considered, but they are rarely needed
Canine granulomatous enteritis or colitis is diagnosed if good ultrasound support is available. Finding a foreign
histologically and is usually caused by fungi or algae, and object is usually sufficient to establish a diagnosis, but not all
sometimes by bacteria. Idiopathic granulomatous infiltrates foreign objects cause obstruction.
are uncommon. The clinician should request special stains,
culture, and perhaps PCR testing before diagnosing idio- Treatment
pathic granulomatous disease. Regardless of cause, clini- If an abdominal mass, foreign object, or obstructive ileus is
cal signs are typically more severe than most cases of large found, a presumptive diagnosis of obstruction is typically
bowel disease and may often cause a protein-losing enter- made, and endoscopy or exploratory surgery is planned.
opathy. If it is idiopathic and the disease is localized, surgical Routine preanesthetic laboratory tests with subsequent sta-
resection should be considered. If it is diffuse, glucocorti- bilization of the patient are indicated before proceeding to
coids and cyclosporine may be considered. Too few cases endoscopy or surgery.
of idiopathic granulomatous enteritis or colitis have been
described and treated to allow generalizations. The prognosis Prognosis
is poor. If septic peritonitis is absent and massive intestinal resection
is not necessary, the prognosis is usually good.

INTESTINAL OBSTRUCTION INCARCERATED INTESTINAL
OBSTRUCTION
SIMPLE INTESTINAL OBSTRUCTION
Etiology
Etiology
Incarcerated intestinal obstruction involves a loop of intes-
Simple intestinal obstruction (i.e., lumenal obstruction tine trapped or “strangulated” as it passes through a hernia
without peritoneal leakage, severe venous occlusion, or (e.g., abdominal wall, mesenteric) or similar rent. The
bowel devitalization) is usually caused by foreign objects. entrapped intestinal loop quickly dilates, accumulating fluid
Infiltrative disease and intussusception may also be in which bacteria flourish and release endotoxins. SIRS
responsible. occurs rapidly. This is a true surgical emergency, and animals
deteriorate quickly if the entrapped loop is not removed.
Clinical Features
Simple intestinal obstructions usually cause vomiting with Clinical Features
or without hyporexia, depression, or diarrhea. Abdomi- Dogs and cats with incarcerated intestinal obstruction typi-
nal pain is uncommon. The more orad the obstruc- cally have acute vomiting, abdominal pain, and progressive
tion, the more frequent and severe vomiting tends to be. depression. Palpation of the entrapped loop often causes
If the intestine becomes devitalized and septic peritonitis severe pain and occasionally vomiting. On physical exami-
results, the animal may be presented in a moribund state or nation, “muddy” mucous membranes and tachycardia may
in SIRS. be noted, suggesting SIRS.