Common bile duct obstruction due to a duodenal gastrinoma in a dog

Canine hepatobiliary anatomy, physiology and congenital disorders

The biliary system is an integral component of normal physiologic homeostasis and essential for survival. It acts as a conduit for the removal of detoxified and catabolised compounds as well as aids in fat digestion and absorption. Derangements in this system can have dangerous sequela that are associated with varying degrees of morbidity and mortality. Moreover, abnormalities in development of the biliary system can have varied and unpredictable changes on function and long-term outcome. The aims of this article were to review canine hepatobiliary anatomy, physiology and cholestasis as well as summarise congenital biliary disorders including human corollaries.

Gastrinoma and Zollinger-Ellison syndrome in canids: a literature review and a case in a Mexican gray wolf

Gastrinoma, an infrequent diagnosis in middle-aged dogs, occurs with nonspecific gastrointestinal morbidity. Laboratory tests can yield a presumptive diagnosis, but definitive diagnosis depends on histopathology and immunohistochemistry. We describe a malignant pancreatic gastrinoma with lymph node metastases and corresponding Zollinger-Ellison syndrome in a Mexican gray wolf ( Canis lupus baileyi) and review this endocrine neoplasm in domestic dogs. A 12-y-old, captive, male Mexican gray wolf developed inappetence and weight loss. Abdominal ultrasonography revealed a thickened duodenum and peritoneal effusion. Two duodenal perforations were noted on exploratory celiotomy and were repaired. Persisting clinical signs led to a second celiotomy that revealed a mesenteric mass, which was diagnosed histologically as a neuroendocrine carcinoma. During the following 16 mo, the wolf received a combination of H₂-receptor antagonists, proton-pump inhibitors, gastroprotectants, and anti-emetics, but had recurrent episodes of anorexia, nausea, acid reflux, and remained underweight. Worsening clinical signs and weakness prompted euthanasia. The antemortem serum gastrin concentration of 414 ng/L (reference interval: 10-40 ng/L) corroborated hypergastrinemia. Autopsy revealed a mass expanding the right pancreatic limb; 3 parapancreatic mesenteric masses; duodenal ulcers; focal duodenal perforation with septic fibrinosuppurative peritonitis; chronic-active ulcerative esophagitis; and poor body condition. The pancreatic mass was diagnosed histologically as a neuroendocrine carcinoma and the parapancreatic masses as lymph node metastases. Immunohistochemistry of the pancreatic mass was positive for gastrin and negative for glucagon, insulin, pancreatic polypeptide, serotonin, somatostatin, and vasoactive intestinal peptide.

Malignant pancreatic gastrinoma in a maned wolf (Chrysocyon brachyurus): case report

ABSTRACT A captive 12-year-old female maned wolf (Chrysocyon brachyurus), previously diagnosed with visceral leishmaniasis, developed severe myiasis in the right ear, followed by prostration and death. A firm solid nodule, measuring 1 x 3cm, was grossly observed in the pancreas. Histologically, there was neoplastic proliferation in the pancreas and pancreatic lymph node. Neoplastic cells had a neuroendocrine pattern, and were positive for gastrin and pancreatic polypeptide by immunohistochemistry. The wolf had also ulcerative gastritis. To the best of our knowledge is the first reported case gastrinoma in this species.

Effect of gastric acid-suppressive therapy and biological variation of serum gastrin concentrations in dogs with chronic enteropathies

BACKGROUND

Serum gastrin concentration can help diagnose gastrinomas in dogs if >3-10× the upper reference limit (URL), but antisecretory therapy and other conditions can also cause hypergastrinemia. Effects of antisecretory therapy (famotidine or ranitidine, omeprazole) on serum gastrin concentration in dogs with chronic enteropathy (CE) and its biological variation (BV) are unknown. Aim of the study was to evaluate serum gastrin in acid-suppressant-treated or -naïve CE dogs; test the association between serum gastrin and histopathologic findings in acid-suppressant-naïve CE dogs; and evaluate the BV of serum gastrin in dogs not receiving any gastric acid suppressive therapy. Samples from 231 dogs were used and serum gastrin was measured by chemiluminescence assay. Gastric and duodenal histologic lesions were evaluated and graded. BV of serum gastrin was evaluated in serial samples.

RESULTS

Serum gastrin concentrations were significantly higher in acid-suppressant-treated than acid-suppressant-naïve dogs (P = 0.0245), with significantly higher concentrations in proton pump inhibitor (PPI)- than H2-antihistamine-treated patients (P = 0.0053). More PPI- than H2-antihistamine-treated dogs had gastrin concentrations above URL (P = 0.0205), but not >3× nor >10× the URL. Serum gastrin concentrations correlated with the severity of gastric antral epithelial injury (P = 0.0069) but not with any other lesions or the presence/numbers of spiral bacteria in gastric biopsies. Intra- and inter-individual BV were 43.4 and 21.6%, respectively, in acid-suppressant-naïve dogs, with a reciprocal individuality index of 0.49 and a critical difference of ≥29.5 ng/L.

CONCLUSIONS

Antisecretory (particularly PPI) treatment leads to hypergastrinemia in CE dogs, but the concentrations seen in this study are unlikely to compromise a diagnosis of gastrinoma. Use of a population-based URL for canine serum gastrin and a URL of ≤27.8 ng/L are appropriate.

Gastroduodenal Ulceration in Small Animals: Part 1. Pathophysiology and Epidemiology

Gastroduodenal ulceration in small animals is a complex and important comorbidity that occurs when the physiological homeostasis of the gastrointestinal tract is disrupted secondary to administration of medications or the presence of local or systemic diseases. The aim of this article is to provide a comprehensive review of the veterinary literature regarding the pathophysiology, epidemiology, and risk factors associated with gastroduodenal ulceration in small animals. Pertinent concepts from the human literature will be integrated into the discussion. This article serves as an introduction to the second part of this series, which will review current evidence regarding the use of H2-receptor antagonists and proton pump inhibitors in small animals.

Normal dogs treated with famotidine for 14 days have only transient increases in serum gastrin concentrations

BACKGROUND

In people, serum gastrin concentrations increase in response to administration of H(2) receptor antagonists, but the effect of famotidine administration on serum gastrin concentrations has not been evaluated in dogs.

OBJECTIVES

To determine if serum gastrin concentrations increase in response to 14 days of famotidine treatment and the time needed to return to baseline after discontinuation of famotidine; define stability of gastrin in samples held at room temperature.

ANIMALS

Eleven healthy dogs were included in part A (famotidine treatment) and 7 healthy dogs in Part B (serum gastrin stability). In part A, famotidine (0.5 mg/kg p.o. q12h) was administered for 14 days. Fasting blood samples were collected on days 0, 3, 7, 11, 14, 16, 18, 20, and 22. In part B, blood was collected after a 12-hour fast. Gastrin concentrations in serum samples held at room temperature for ≤30 minutes after sampling were compared to concentrations in samples held at room temperature for 150 minutes after sampling.

RESULTS

Serum gastrin concentrations increased by day 3 of famotidine administration and returned to baseline concentrations in all dogs by day 14 despite continued famotidine administration. Serum gastrin concentrations were lower (20% mean decrease; P = .0005) in samples held at room temperature for 150 minutes.

CONCLUSIONS AND CLINICAL IMPORTANCE

After 14 days of famotidine administration, clinically healthy dogs have normal serum gastrin concentrations. In a dog with clinical features consistent with gastrinoma, chronic famotidine administration is unlikely to contribute to increases in serum gastrin concentrations.

Emesis in dogs: a review

Emesis is a common presenting sign in small animal practice. It requires a rational approach to management that is based upon a sound understanding of pathophysiology combined with logical decision making. This review, which assesses the weight of available evidence, outlines the physiology of the vomiting reflex, causes of emesis, the consequences of emesis and the approach to clinical management of the vomiting dog. The applicability of diagnostic testing modalities and the merit of traditional approaches to management, such as dietary changes, are discussed. The role and usefulness of both traditional and novel anti-emetic drugs is examined, including in specific circumstances such as following cytotoxic drug treatment. The review also examines areas in which common clinical practice is not necessarily supported by objective evidence and, as such, highlights questions worthy of further clinical research.

Mucinous Gastric Carcinoma With Abdominal Carcinomatosis and Hypergastrinemia in a Dog

A 12-year-old, spayed female Australian cattle dog was evaluated for a 5-month history of progressive vomiting. Abdominal radiographs and ultrasound revealed significant gastric wall thickening and a peripancreatic mass, and serum gastrin concentration was increased (127 pg/mL, reference range 10 to 40 pg/mL). Surgical exploration of the abdomen revealed a thickened, firm, and irregular gastric fundus, pylorus, and antrum; nodules were present throughout the spleen and mesentery adjacent to the left limb of the pancreas. Mucinous gastric carcinoma with carcinomatosis was diagnosed by histopathological examination of surgically excised tissues. Unfortunately, severe postoperative complications resulted in euthanasia 10 days after surgery, and a necropsy was not performed. This case is significant, because it is the first report of a mucinous gastric carcinoma associated with hypergastrinemia in a dog.

Canine gastrinoma: a case study and literature review of therapeutic options

CASE HISTORY

A 6.2 kg, 8-year-old, spayed female Australian Terrier was presented with weight loss, inappetence, lethargy and a 2-day history of intermittent vomiting.

CLINICAL FINDINGS

The dog had cranial abdominal pain and there was melaena present on digital rectal examination. Haematology revealed a marked, acute leucogram.

DIAGNOSIS AND TREATMENT

Fasting serum gastrin levels were markedly elevated and gastrinoma was suspected. Treatment was initiated with omeprazole, ranitidine and sucralfate. The dog remained clinically normal for 26 months, at which time exploratory surgery was undertaken and the dog subsequently euthanised due to extensive metastases. Histopathology and immunocytochemistry confirmed the diagnosis of metastatic gastrinoma.

CLINICAL RELEVANCE

This is a rare condition infrequently reported. Although the number of cases treated with omeprazole are too few to draw firm conclusions, it would appear that proton pump inhibitors are useful and should be considered for cases of gastrinoma managed medically. Long-term prognosis is poor, and survival times range from 1 to 147 weeks. Many treatment options are discussed in the medical literature though not all are feasible in veterinary patients.

Cholecystoenterostomy for treatment of extrahepatic biliary tract obstruction in cats: 22 cases (1994–2003)

OBJECTIVE

To identify factors associated with outcome in cats with extrahepatic biliary tract obstruction (EHBTO) that undergo biliary diversion surgery.

DESIGN

Retrospective case series.

ANIMALS

22 cats.

PROCEDURES

Medical records of cats with surgically confirmed EHBTO that underwent cholecystoenterostomy were reviewed.

RESULTS

Clinical signs and physical examination findings included vomiting, anorexia, icterus, lethargy, weakness, and weight loss. Common clinicopathologic abnormalities included high serum hepatic enzyme activities and serum bilirubin concentration. Abdominal ultrasonography was performed in 21 cats, and all 21 had findings consistent with EHBTO. Eleven of 15 cats in which blood pressure was monitored had intraoperative hypotension. Eighteen cats had anemia following surgery, and 14 cats had persistent hypotension. Extrahepatic biliary tract obstruction was a result of neoplasia in 9 cats and chronic inflammatory disease in 13. Fourteen cats survived long enough to be discharged from the hospital, but only 6 survived > 6 months after surgery, all of which had chronic inflammatory disease. Median survival time for cats with neoplasia (14 days) was significantly shorter than that for cats with inflammatory disease (255 days). No other variable was associated with outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that cats with EHBTO secondary to neoplasia have a poorer prognosis than cats with EHBTO secondary to chronic inflammatory disease. However, the overall prognosis for cats with EHBTO undergoing cholecystoenterostomy must be considered guarded to poor, and the incidence of perioperative complications is high.