Gastrointestinal Medicine and Surgery Cases

There are many causes of vomiting, diarrhea, and icterus in dogs and cats. Gastrointestinal (GI) signs can be the result of primary diseases of the GI system or secondary GI diseases. Secondary GI diseases associated with vomiting are fairly common and include renal diseases, liver diseases, and pancreatitis. The most common secondary GI causes of diarrhea are hyperthyroidism, exocrine pancreatic insufficiency (rare in cats), and hypoadrenocorticism (rare in cats). Differential diagnoses for primary GI diseases are often grouped into obstruction (masses, foreign body, and intussusception), dietary intolerance, drugs/toxins (garbage gut), inflammatory bowel diseases, neoplasia, infectious diseases, and parasites. Secondary GI diseases can often be excluded from the differential list by use of blood tests. However, abdominal organ biopsies may be need. Primary GI cases can often be treated medically, but some may require surgical intervention. In addition, it is well documented that the gastrointestinal tract will heal much quicker if fed enterally and so the use of appetite stimulants and feeding tube is common in veterinary medicine. Management of vomiting and diarrhea has been discussed in other parts of the proceedings. In this case based lecture series, we plan to use case presentations to introduce additional medical and surgical concepts.

Abdominal Organ Biopsy

Exploratory laparotomy can be used as a diagnostic tool in cases of chronic vomiting and/or diarrhea or peritoneal effusion of unknown etiology. Liver and lymph node biopsies are indicated in cases of suspected malignancy to determine extent and spread of disease. Most organs in the abdominal cavity can be sampled with relative ease.

Liver:
There are multiple methods for sampling the liver. If there is a distinct lesion that needs to be sampled, its size and location often dictate the biopsy method. For diffuse disease or routine sampling, the liver can be biopsied along the edge or margin. Marginal biopsies can be performed using a guillotine method, multiple mattress sutures, or stapling equipment. Lesions away from the edge can be sampled using Baker skin biopsy punch or Tru-cut biopsy instrument. Hemorrhage can be controlled using digital pressure, electrocoagulation, or hemostatic agents such as Gelfoam® or Surgicel®.

Stomach:
Gastric biopsies are most commonly obtained through endoscopy. However, sampling by this method only retrieves pieces of the gastric mucosa. Surgical sampling retrieves full-thickness sections that may be beneficial in diagnosing schirrous gastric neoplasia that typically infiltrates deeper layers. Routine surgical biopsy is performed either in the ventral aspect of the body of the stomach between the lesser and greater curvature or in the left lateral aspect of the stomach if a gastrostomy tube is going to placed. A stab incision is made into the lumen of the stomach and extended 1 to 2 cm. A sample is taken from one edge of the incision using Metzenbaum scissors. All layers of the stomach should be sampled. The site is closed using a singlelayer full-thickness simple continuous pattern with 3-0 monofilament absorbable suture. [...]