Page 458 - Small Animal Internal Medicine, 6th Edition

430 PART III Digestive System Disorders

biopsied is visualized, but the clinician may blindly pass the entire abdomen should be examined (i.e., literally from the
biopsy forceps through the ileocolic valve to biopsy the beginning of the stomach to the end of the colon along with
VetBooks.ir ileum if the tip of the endoscope cannot be advanced into all parenchymal organs). Biopsy specimens of the stomach,
duodenum, jejunum, ileum, mesenteric lymph nodes, and
these areas.
Not all laboratories are adept at processing and interpret-
less of how normal these organs appear, unless an obvious
ing endoscopic samples of intestinal tissue. Endoscopes with liver (and the pancreas in cats) should be obtained, regard-
2.8-mm biopsy channels are generally preferred to those lesion (e.g., a large tumor) is found. The colon is more likely
with a 2.0- or a 2.2-mm channel because the larger forceps to dehisce than the small intestine, and full thickness colonic
allow retrieval of substantially larger and deeper tissue biopsies should be avoided unless there is an overriding
samples. reason to do them. It is wise not to assume that a grossly
When intestinal or gastric mucosa is biopsied, the tissue impressive lesion is responsible for the clinical signs; rather,
sample must be handled carefully to minimize artifacts and the clinician usually should perform a biopsy even when the
distortion. The tissue should be carefully removed from the diagnosis seems obvious. Dehiscence is a major risk if biopsy
biopsy forceps with a 25-gauge needle. A squash preparation is occurring in an abdomen that already has septic peritoni-
of one tissue specimen can be evaluated cytologically, and tis present. It is a concern if the serum albumin concentra-
the remaining samples are fixed in formalin and evaluated tion is less than 1.5 g/dL, but excellent technique minimizes
histologically. The cytology slides should be evaluated by a the risk. The clinician should consider whether esophagos-
pathologist familiar with GI cytology. Cytologic preparations tomy, gastrostomy, or enterostomy feeding tubes should be
of the gastric mucosa may show adenocarcinoma, lym- placed in emaciated animals before exiting the abdomen.
phoma, various inflammatory cells, or spirochetes (see Fig.
30.1). Cytologic studies of the intestinal mucosa may show Suggested Readings
eosinophilic enteritis, lymphoma, histoplasmosis, or proto- Allenspach K. Diseases of the large intestine. In: Ettinger SJ, et al.,
thecosis, and occasionally giardiasis, bacteria, or Heterobil- eds. Textbook of veterinary internal medicine. 7th ed. St Louis:
harzia ova. Cytology is specific but insensitive (i.e., failing to WB Saunders; 2010.
find something does not allow the clinician to eliminate it). Bonadio CM, et al. Effects of body positioning on swallowing on
The laboratory should be consulted regarding the proper esophageal transit in healthy dogs. J Vet Intern Med. 2009;23:
way to submit endoscopic tissue samples. To simply submit 801.
intestinal tissues floating freely in formalin almost guaran- Bonfanti U, et al. Diagnostic value of cytologic examination of
tees that few if any pieces will be optimally oriented on the gastrointestinal tract tumors in dogs and cats: 83 cases
(2001-2004). J Am Vet Med Assoc. 2006;229:1130.
histopathology slide. The clinician should place tissues from Cartwright JA, et al. Evaluating quality and adequacy of gastro-
different locations in different vials of formalin; each vial intestinal samples collected using reusable or disposable forceps.
should be properly labeled. Small tissue samples should not J Vet Intern Med. 2016;30:1002.
be allowed to dry out or be damaged before placement in Davignon DL, et al. Evaluation of capsule endoscopy to detect
formalin. mucosal lesions associated with gastrointestinal bleeding in dogs.
Two common problems with endoscopically obtained J Small Anim Pract. 2016;57:148.
tissue samples are that the sample is too small or there is Dryden M, et al. Accurate diagnosis of Giardia spp. and proper
excessive artifact. Lymphomas are sometimes relatively deep fecal examination procedures. Vet Ther. 2006;7:4.
in the mucosa (or are submucosal), and a superficial biopsy Gaschen L, et al. Comparison of ultrasonographic findings with
specimen may then show only a tissue reaction above the clinical activity index (CIBDAI) and diagnosis in dogs with
chronic enteropathies. Vet Radiol Ultrasound. 2009;49:56.
tumor, resulting in a misdiagnosis of inflammation. Multiple Gould E, et al. A prospective, placebo-controlled pilot evaluation
biopsy specimens should be obtained until there are at least of the effects of omeprazole on serum calcium, magnesium,
six to eight samples of excellent size and depth (i.e., the full cobalamin, gastrin concentrations, and bone in cats. J Vet Intern
thickness of mucosa). It is important for the pathologist to Med. 2016;30:779.
inform the clinician whether or not the quality of the tissue Grooters AM, et al. Development of a nested polymerase chain
samples was adequate for evaluation and if the severity of the reaction assay for the detection and identification of Pythium
histologic lesions found is consistent with the severity of insidiosum. J Vet Intern Med. 2002;16:147.
clinical signs. Gualtieri M. Esophagoscopy. Vet Clin North Am. 2001;31:605.
Hall EJ, et al. Diseases of the small intestine. In: Ettinger SJ, et al.,
FULL-THICKNESS BIOPSY eds. Textbook of veterinary internal medicine. 7th ed. St Louis:
If endoscopy is not available, abdominal surgery may be WB Saunders Elsevier; 2010.
needed to perform gastric and intestinal biopsies. Full- Hardy BT, et al. Multiple gastric erosions diagnosed by means of
capsule endoscopy in a dog. J Am Vet Med Assoc. 2016;8:926.
thickness biopsy specimens obtained surgically can have Jergens A, et al. Endoscopic biopsy specimen collection and histo-
fewer artifacts than those obtained endoscopically; however, pathologic considerations. In: Tams TR, et al., eds. Small animal
the clinician must consider the pros and cons of surgery in endoscopy. 3d ed. St Louis: Elsevier; 2011.
a potentially debilitated or ill animal. Endoscopy allows the Jergens AE, et al. Maximizing the diagnostic utility of endoscopic
clinician to direct the biopsy forceps to lesions that cannot biopsy in dogs and cats with gastrointestinal disease. Vet J.
be seen from the serosal surface. If surgery is performed, the 2016;214:50.