Page 1093 - Cote clinical veterinary advisor dogs and cats 4th

544 Inflammatory Bowel Disease

ASSOCIATED DISORDERS • In some instances, IBD is associated with ○ Liver enzymes may point to concomitant
• Dog: severe IBD may cause PLE and/or mucosa-adhesive bacteria such as Escherichia liver or pancreatic disease (e.g., feline
VetBooks.ir • Cat: triaditis with concurrent IBD, cholan- • IBD may predispose to GI lymphoma • Abdominal radiographs: rule out intestinal
triaditis).
coli (e.g., canine granulomatous colitis, feline
intestinal lymphangiectasia (p. 600)
IBD).
obstruction, especially if vomiting
gitis, and pancreatitis; prevalence unknown
(p. 604)
(pp. 160 and 740)
• Abdominal ultrasound: fair sensitivity, good
specificity. Focal or diffuse loss of intestinal
Clinical Presentation wall layering, mucosal striations or spicules,
DISEASE FORMS/SUBTYPES DIAGNOSIS wall thickening, enlarged and/or hypoechoic
• Clinical signs vary, depending on which Diagnostic Overview mesenteric lymph nodes may be detected.
segment of the intestine is involved. The diagnosis of IBD requires exclusion of other Localization of lesions may help decide
• Subtypes are often described by the type of causes for the clinical signs, and GI biopsies best approach for biopsies (endoscopy or
inflammation (i.e., lymphocytic-plasmacytic, for confirmation of inflammation. celiotomy).
eosinophilic, suppurative, or granulomatous • Serum cobalamin and folate concentrations
[p. 395]). Differential Diagnosis (pp. 1325 and 1344)
• IBD or CE can be subtyped on the basis of • For diarrhea (p. 1213) • Consider baseline cortisol or ACTH stimula-
clinical response, including food responsive • For chronic vomiting (p. 1294) tion test (dog) to rule out hypoadrenocorti-
(p. 347), antibiotic responsive (p. 260), or • For hypoalbuminemia (p. 1239), including cism
steroid responsive. lymphangiectasia (dog) • Serum thyroxine concentration (cat > 5 years)
GI signs and histologic evidence of GI to rule out hyperthyroidism
HISTORY, CHIEF COMPLAINT inflammation: • Rectal scrape (p. 1157): look for pathogens
• Mild IBD may cause intermittent clinical • Infiltrative intestinal neoplasia (e.g., alimen- (e.g., Histoplasma, Pythium) if in endemic area
signs, whereas severe IBD is characterized tary lymphoma, especially in cats)
by severe, progressive clinical signs. • Infectious diseases Advanced or Confirmatory Testing
• Dogs are presented for evaluation of chronic ○ Fungal enterocolitis (e.g., Histoplasma) • Upper and/or lower GI endoscopy (p. 1098):
small- or large-bowel diarrhea (p. 1215). ○ Bacterial enterocolitis (e.g., in dogs, Cam- assess mucosa, sample at least eight deep
○ Small-intestinal: decreased appetite, weight pylobacter spp, Campylobacter perfringens, biopsies per anatomic site.
loss, vomiting, and lethargy Campylobacter difficile); rarely a primary • Celiotomy if endoscopy is not available,
○ Large intestinal: characteristic diarrhea, disease lesions are inaccessible by endoscopy, or
occasionally vomiting ○ Granulomatous enteritis associated with full-thickness biopsies are desirable (avoid
• Cats are usually presented for evaluation of pythiosis, protothecosis, or schistosomiasis full-thickness biopsy of colon)
chronic vomiting, which may or may not be • Histopathologic analysis: objective is to
associated with diarrhea. Hyporexia/anorexia, Initial Database confirm and evaluate severity of mucosal
weight loss, and lethargy are common. • Perform fecal parasitologic exams (flotation lesions (inflammation, architecture) and to
and direct) to rule out nematodes, protozoa, rule out neoplastic or pathogen infiltration.
PHYSICAL EXAM FINDINGS and Giardia (consider Giardia antigen test) Pathologists should use current reporting
Small-intestinal disease: in animals with diarrhea. standards (i.e., World Small Animal Veteri-
• Poor body condition with poor haircoat is ○ Alternatively, empirical treatment with nary Association guidelines).
common with severe disease. broad-spectrum anthelminthic drug (e.g., ○ In cats, immunohistochemistry and
• Dehydration is possible. fenbendazole 50 mg/kg PO q 24h for 3-5 polymerase chain reaction (PCR) for
• Thickened small-intestinal loops may days) antigen receptor rearrangement (PARR)
occasionally be palpated (cats). • If the animal seems well other than mild are recommended to differentiate IBD
• Animals occasionally show pain or discomfort to moderate GI signs, a diet trial is a from alimentary small cell lymphoma.
on abdominal palpation. reasonable next step. Up to 70% of dogs
• Ascites, pleural effusion, and peripheral with chronic diarrhea and 50% of cats TREATMENT
edema can occur in PLE. with chronic GI signs respond within
Large-intestinal disease: 2 weeks to empirical dietary trial using Treatment Overview
• Usually unremarkable; may be associated novel protein or hydrolyzed peptide diet In cases with mild to moderate disease severity,
with abdominal discomfort in severe cases (p. 347). a dietary elimination trial should be completed,
• Mucoid and/or bloody stool during rectal • Dogs that fail elimination trial may benefit and possibly followed by an antibiotic trial,
exam; sometimes thickened or irregular rectal from antibiotic treatment with tylosin before considering immunosuppressive therapy.
mucosa 25 mg/kg PO q 12-24h or metronidazole Only if these fail and infectious causes of clinical
10-15 mg/kg PO q 12h (p. 260). signs have been reasonably excluded should
Etiology and Pathophysiology • If empirical treatment fails or animal immune suppression be considered. The goal
• Abnormal interactions between intestinal demonstrates more than mild clinical signs, of therapy is to control clinical signs because
microbiota and innate/adaptive immune additional testing is required. a cure may be unattainable.
response • CBC: useful to rule out other differential
• Breakdown of the intestinal mucosal barrier diagnoses Acute and Chronic Treatment
and exposure of lamina propria to luminal • Serum biochemistry: helps rule out or • Empirical deworming, as above
antigens, with subsequent uncontrolled generate suspicion of other differential • Diet trial (hypoallergenic or novel antigen),
immune response diagnoses (e.g., kidney or liver disease, as above
• Inflammation causes changes in mucosal hypoadrenocorticism) • Antibiotic trial (tylosin or metronidazole),
architecture and ultracellular structure ○ Panhypoproteinemia associated with severe as above
of enterocytes and ultimately results in disease (dog) • Probiotics may have beneficial effects as
abnormal function. ○ Low total and ionized serum calcium adjunctive treatment.
• Protein loss reflects poor absorptive func- reflect hypoalbuminemia (total calcium), • Supportive treatment (e.g., IV fluids,
tion and/or inflammatory exudation or malabsorption of vitamin D (ionized antiemetics) as necessary based on clinical
ulceration. calcium) findings

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