Veterinary Clinical Medicine-I (General and Systemic)

DIAGNOSIS

Differential diagnosis

• Neoplasia—lymphoma and adenocarcinoma
• Irritable bowel syndrome
• Rectocolonic polyps
• Cecal inversion
• Ileocecocolic intussusception

CBC/Biochemistry/Urinalysis

• Results usually normal; neutrophilia with a left shift is possible; eosinophilia occasionally observed in eosinophilic colitis, parasitism, and pythiosis/phycomycosis
• Mild microcytic, hypochromic anemia may occur in some patients with persistent bleeding.
• Rare hyperglobulinemia in some patients (especially cats) with chronic disease.

Other laboratory tests

• Examination of fecal floatation, direct fecal smear, bacterial culture, or fungal culture (Pythium) may reveal an infectious cause.
• Feces may test positive for Clostridium perfringens toxin.

Imaging

• Abdominal radiographs—usually normal
• Barium enema—may reveal mucosal irregularities or filling defects in severely affected patients, but this procedure is time-consuming and not cost-effective
• Abdominal ultrasonography—may reveal masses, diffuse thickening, or altered architecture; can perform guided biopsies or fine-needle aspiration

Other diagnostic procedures

• Colonoscopy with biopsy—technique of choice for diagnosis; may see disappearance of submucosal blood vessels, granular appearance of mucosa, hyperemia, excessive mucus, ulceration, pinpoint hemorrhage (small ulcerations), or mass
• Always take multiple biopsy specimens because the extent of mucosal change does not necessarily reflect severity or absence of disease.

Pathologic findings

• Gross findings as described
• Histopathologic findings depend on the histologic type of colitis—lymphoplasmacytic, eosinophilic, granulomatous, or histiocytic; hyperplastic mucosa may be seen with irritable bowel syndrome; various infectious agents may be seen with special stains.