*4.6.2 Endoscopic appearance of duodenal disorders*

Roth et al. [72, 73, 75] reported that increased granularity and friability associated with increased cellularity within the lamina propria were due to the inflammation or neoplasm of duodenum. Richter [42] described endoscopic appearance of duodenal ulcer as deep or shallow crater and well demarcated from the surrounding mucosa.

Forsyth et al. [76] described mucosal grading scale for ulceration study as follows: 0, no visible hemorrhage and erosions/ulcers; 1+ , 1–5 punctate erosions and hemorrhage; 2+ , 6–15 punctate erosions and hemorrhage; 3<sup>+</sup> , 16–25 punctate erosions and hemorrhage; 4+ , ≥25 punctate erosions and hemorrhage and 1–5 invasive erosions; 5+ , ≥5 invasive erosions; and 6+ , ulcer of any size (**Figure 2**).

Yamasaki et al. [77] reported that endoscopic appearance of duodenum in lymphocytic-plasmacytic enteritis had mucosal friability and mucosal destruction and hemorrhage when the mucosa was gently touched with endoscope, which was not observed in normal duodenum of dog. Leib and Matz [43] reported that endoscopic appearance of duodenum in IBD-affected dogs was hyperemia, mucosal hemorrhage, ulceration, increased mucosal granularity, and friability. Lecoindre [78] observed a multifocal, pale, papular, and granular appearance of duodenum in lymphangiectasia in dogs. Miura et al. [79] and Snead [80] reported endoscopic appearance of duodenal neoplasia as ulceration, irregular mucosa, hyperemia, cobble stone or granular texture, and friability (**Figure 3**). Walker [81] recognized the diseased duodenum during duodenoscopy as reddened, ulcerated, thickened (**Figure 4**), and abnormally fibrosed or friable such that it bled abnormally following contact with the tip of the scope or after taking biopsy.

Freiche and Poncet [82] recorded increased granularity of mucosa and erythema of the proximal duodenum with highly visible Peyer's patches in brachycephalic breeds affected with upper airway and gastrointestinal syndrome. Sancho et al. [83] evaluated the endoscopic appearance of the descending duodenum in lymphocytic-plasmacytic enteritis and scored as follows: (1) intestinal lumen (0 = normal, 1 = narrowed due to

**Figure 2.** *Duodenoscopy: duodenal ulceration cum perforation.*

**Figure 3.** *Duodenoscopy: duodenal ulceration in plasmacytic enteritis.*

#### **Figure 4.**

*Duodenoscopy: highly fragile duodenal mucosa in inflammatory bowel disease.*

**Figure 5.** *Duodenoscopy: duodenal foreign body—thread in the proximal duodenum.*

lack of elasticity), (2) mucosal erythema (0–3 depending on the degree of alteration), (3) mucosal granularity (0–3 depending on the degree of alteration), (4) irregular mucosa (0–3 depending on the degree of alteration), (5) friable mucosa (0–3 depending on the degree of alteration), and (6) erosions/ulcers (0–3 depending on the degree of alteration). And from this total score, the macroscopic and endoscopic duodenal lesions of the dogs were classified as normal duodenum (0 point), mild LPE (1–4, up to 25% of the maximum score), moderate LPE (5–8, up to 25–50% of the maximum score), and severe LPE (9–16, >50% of the maximum score).

*An Update on Canine Duodenal Disorders DOI: http://dx.doi.org/10.5772/intechopen.86049*

**Figure 6.** *Duodenoscopy: duodenal foreign body—stones and bone pieces in the proximal duodenum.*

#### *4.6.3 Endoscopy-aided biopsy of duodenum*

Willard et al. [84] and Michael et al. [85] stated that the endoscopic biopsy of the duodenal mucosa had been an important tool in the diagnosis of small intestinal tract diseases of dogs. Obtaining excellent duodenal tissue samples was typically harder than obtaining samples from other portions of the gastrointestinal tract, and they also opined that it was easier to obtain high-quality tissue samples from the descending duodenum than ascending duodenum [86]. Jergens et al. [87] suggested that the multiple mucosal biopsy specimens were required for diagnosis of inflammatory bowel disease. Full-thickness biopsy of intestine was necessary to diagnose alimentary lymphoma, because lesions were usually deep seated and invaded the serosal layer [79].

The definitive diagnosis of IBD was obtained by histological examination of intestinal biopsies [12]. Walker [81] and Spillmann [88] reported that biopsy samples of ulcer condition should be obtained from the periphery of the lesion. Freiche and Poncet [82] observed lymphoplasmacytosis as a principle lesion from duodenal biopsies in brachycephalic dogs affected with upper airway and gastrointestinal syndrome. Bexfield [89] reported that biopsy could be performed by the use of flexible pinch biopsy forceps.

#### *4.6.4 Endoscopy-aided brush cytology*

Jergens et al. [90] and Zoran [3] observed that endoscopy-aided brush technique was most useful in detecting cellular infiltration in lamina propria and was considered as a reliable adjunct to histological examination of biopsy specimen in the diagnosis of GI diseases of dogs and cats.

#### *4.6.5 Endoscopy-aided collection of duodenal juice*

Pitts et al. [91], Roudebush and Delivorias [92], and Leib et al. [20] reported that aspirate of duodenal content revealed a *Giardia* trophozoite on microscopic examination of the sediments and it was more sensitive than zinc sulfate fecal flotation technique. Hall [55] stated that duodenal juice could be collected during duodenoscopy for diagnosis of SIBO.

#### **4.7 Histopathology and brush cytology**

Dow et al. [93] observed slightly blunted and thickened duodenal villi and increased infiltration of inflammatory cells in the dogs with duodenal ulcer (**Figure 7**). Willard

et al. [94] and Rutgers et al. [15] reported that histologic and intestinal mucosal cytologic examinations were not useful in detecting SIBO. Jergens et al. [52] and Yamasaki et al. [77] stated that duodenal mucosa in clinically normal dogs had low numbers of lymphocytes, histiocytes, plasma cells, and eosinophils. The severity of lymphangiectasia was graded by counting the number of dilated lacteals per low-power (10× objective) field. Ridgway et al. [53] observed increased mucosal granularity of duodenum, mucosal cellular infiltration, and architectural alteration in lymphocytic-plasmacytic enteritis (**Figure 8**).

Potoenjak et al. [38] reported histopathological appearances of lymphangiectasia, and there were dilated lacteals of small intestinal villi, lymphatics, focal infiltration of lamina propria with mononuclear cells particularly plasma cells, and mild edema of the lamina propria (**Figures 9**, **10**). Duodenal biopsy revealed severe fibrosis of the submucosa and infiltrate of small pockets and cards of round to polygonal cells with granular cytoplasm in duodenal gastrinomas [19].

Cytological examination of intestinal lymphosarcoma revealed large, atypical granular lymphocytes containing irregularly shaped, magenta cytoplasmic granules, and in histopathologic examination, diffuse infiltration of the lamina propria of duodenum by a population of large lymphocytes was observed [80]. Jergens [95], Sancho et al. [83], and Day et al. [96] suggested the scoring system

**Figure 7.** *Excessive loss of duodenal villus epithelium in duodenal ulcer (H&E 10 μm).*

**Figure 8.** *Lymphoplasmacytic infiltration of lamina propria of duodenum in IBD (H&E 10 μm).*

*An Update on Canine Duodenal Disorders DOI: http://dx.doi.org/10.5772/intechopen.86049*

#### **Figure 9.**

*Ulceration of villus epithelium with lymphoplasmacytic infiltration in IBD (H&E 50 μm).*

#### **Figure 10.** *Duodenal brush cytology—vacuolar degeneration of epithelium and MNC cells (5 μm).*

for histopathology of duodenal biopsy samples as follows: intraepithelial lymphocytes, chronic inflammatory cell infiltration, edema, lymphocytic vessel dilation, glandular hyperplasia, and fibrosis scored between 0 and 3 according to the degree of alteration (0 = normal and 3 as the maximum alteration), and from the total score, the microscopic duodenal lesions of the dogs were classified as normal (0 point), mild (1–5, up to 25% of the maximum score), moderate (6–9, 25–50% of the maximum score), and severe (10–18, >50% of maximum score).

#### **4.8 Duodenal juice culture**

Small intestinal bacterial overgrowth was diagnosed by isolation of ≥105 aerobic bacterial colony-forming units or ≥104 anaerobic bacterial colony-forming units from duodenal/proximal jejunal fluid obtained from non-fed dogs [55]. Delles et al. [97] and Batt [16] reported that *Escherichia coli*, *Staphylococcus xylosus*, *Staphylococcus epidermidis*, *Corynebacterium* sp., and *Proteus mirabilis* were the most commonly isolated bacteria from intestinal fluid.

Willard et al. [94], Rutgers et al. [15], and Lecoindre [78] reported that small intestinal bacterial overgrowth was diagnosed by quantitative bacterial culture of duodenal juice samples obtained endoscopically. Johnston [60], German et al. [98], and Marks [59] opined that culture of duodenal juice had been regarded as the gold standard for detecting elevated bacterial counts in SIBO. German et al. [99] stated that in SIBO of German Shepherd dog, the duodenal juice had reduced IgA concentration.

### **4.9 Ultrasound**

Gastrointestinal ultrasonography has become a supporting noninvasive diagnostic tool for intestinal diseases and disorders in dogs. It is used to differentiate inflammation and neoplastic infiltrative disease of the intestine [100, 101]. Ultrasonography can be used to inspect the small intestinal wall thickness, dilatation, and peristalsis as well as for intraluminal, intramural, and extraluminal causes of obstruction [102]. Abdominal ultrasonography has become in many instances a part of the minimum database in conjunction with abdominal radiography for the assessment of intestinal disease [103]. The most common ultrasonographic features of intestinal abnormalities are thickening of the bowel wall, loss of its normal layer, and alterations in the contour of the mucosal and/or serosal surfaces [104]. Thickness, altered wall layering appears to be an important finding which differentiates inflammatory from neoplastic and granulomatous infiltration [105]. In dogs, ultrasonographic examination of the small intestine has been successfully used to identify gastrointestinal tumors [104]. Rudorf et al. [100] concluded in his study that ultrasonography should be used to rule out diseases such as intussusceptions and localized tumors in cases of chronic diarrhea.

Ultrasonographic changes were similar in lymphoplasmacytic enteritis and lymphoma of the small intestine, since the overlapping USG findings of inflammatory and neoplastic disease conditions of the intestinal disorders were only confirmed by histopathology examination, which is necessary for differentiating the diseases [106].

Smith et al. [107] reported that hyperechoic mucosal striations are associated with lacteal dilation and are frequently associated with mucosal inflammation and protein-losing enteropathy in dogs.

Gaschen et al. [101] concluded in his study that intestinal mucosal echogenicity could be used for detecting inflammatory bowel disease than bowel wall thickness with chronic diarrhea in dogs.

#### **4.10 Radiographic examination**

Gaschen [106] reported abdominal survey radiographic examination remains an important part of screening patients with vomiting and diarrhea, and it should be performed in conjunction with the abdominal ultrasonographic examination instances. Radiography of intestine could identify foreign bodies, nails, mass/neoplasia, and obstructions. Contrast radiography can be used as an adjunct in the investigation of GI disease. Barium studies can provide information on GI transit, obstructive lesions, intestinal mass lesions, or disrupted mucosal integrity.

#### **5. Treatment**

Therapeutic protocols for the gastrointestinal disorders are based on the acute or chronicity of the condition. Mostly duodenal disorders are observed with chronic condition because of the non-specific signs. Hence, therapy initiated with symptomatically and appropriated therapeutic regimen is followed after confirming the disease or disorders which are aided by duodenoscopy, histopathology, and bacteriology studies. Herewith some of the commonly using drugs for the various duodenal disorders are as follows.

