Association of Gallbladder Mucocele Histologic Diagnosis with Selected Drug Use in Dogs: A Matched Case-Control Study

Biliary Tract Infections in Dogs

Bacterial biliary tract infections are increasingly recognized in dogs and should be considered in any dog presenting with vomiting, anorexia, and jaundice, particularly if they have abdominal discomfort or pyrexia. Commonly recognized clinicopathologic findings include increased liver enzyme activities, hyperbilirubinemia, and an inflammatory leucogram. Hepatobiliary ultrasound forms a key component of the diagnostic approach to these cases, aiding the identification of dogs that require urgent surgical management due to biliary tract rupture, or that have another surgical condition. Ultrasound also allows guided percutaneous bile sampling to gain a sample for cytology and culture, guiding rational antimicrobial therapy.

Gallbladder Mucocele

Gallbladder mucocele (GBM) formation was rarely reported prior to 20 years ago and has emerged as one of the most common, deadly, and poorly understood causes of gallbladder disease in dogs. Multiple and large retrospective studies inform many aspects of diagnosis, concurrent diseases, surgical treatment, complications, and prognosis of patients with GBM. Studies of pathogenesis are fewer but are beginning to disclose underlying mechanisms for GBM formation.

Nutritional Factors Related to Canine Gallbladder Diseases-A Scoping Review

Gallbladder mucocele, cholelithiasis, choledocholithiasis, and cholecystitis are significant contributors to morbidity and mortality in dogs. The exact etiology of these conditions remains poorly understood, though various factors, such as endocrinopathies, dyslipidemia, and impaired gallbladder motility, have been suggested as potential contributors. Surgical intervention has been described as the first choice of treatment when biliary rupture or obstruction is suspected; however, medical management may be an important part of therapeutic or preventative strategy. Reports of medical management typically involve the use of a choleretic used to stimulate the flow of bile into the duodenum or substances that act as a "hepatoprotective" agent such as S-adenosylmethionine. In people, some nutrients appear to modify bile flow and are used as agents in the prevention and treatment of these conditions in the gallbladder. This paper provides a review of the literature about possible nutritional factors involved in the pathogenesis and treatment of canine gallbladder mucocele and cholelithiasis. Opportunities for the prevention and treatment of common biliary diseases in dogs may include the reduction of dietary fat, control of hyperlipidemia with omega-3 and fiber supplementation, ensuring an adequate supply of amino acids such as methionine and tryptophan, and the evaluation of vitamins such as vitamin D.

Histologic findings of gastrointestinal biopsies and clinical outcome in dogs undergoing cholecystectomy for gallbladder mucoceles: 71 cases (2014-2021)

OBJECTIVES

To determine the presence and categorise the severity of enteritis in dogs with gallbladder mucoceles, and evaluate for any associations with enteritis. This study also aimed to report clinical outcome following cholecystectomy and evaluate for associations with survival.

MATERIALS AND METHODS

Medical records were retrospectively reviewed (2014 to 2021) for dogs undergoing cholecystectomy and duodenal biopsy procedures for gallbladder mucocele. Signalment, bloodwork, abdominal ultrasound findings, surgical details, histology results and outcomes were reported. Surgeries were considered elective or emergent based on each dog's clinical presentation. Enteritis was categorised based on cell type and severity. Inflammation and clinical outcome were statistically evaluated.

RESULTS

Seventy-one dogs met the study criteria. Enteritis was present in 85.9% (61/71) of cases with the majority being lymphoplasmacytic (53.5%). Twelve dogs (16.9%) underwent gastrointestinal biopsies from multiple sites, which revealed the same enteritis type at each location. A total of 87.3% (n = 62) dogs survived, including 90.4% elective and 86% emergent cases. No significant differences in enteritis severity or patient survival were found between elective and emergent cases. Septic peritonitis was diagnosed in two dogs (2.82%). Mortality was significantly associated with leukocytosis, with nonsurviving dogs having a mean WBC count of 27.6 G/L (95% confidence interval: 10.6 to 21.5).

CLINICAL SIGNIFICANCE

Enteritis is present in a majority of dogs with gallbladder mucocele, especially mild to moderate with lymphoplasmacytic cell type. Obtaining a duodenal biopsy had minimal impact on patient outcome. Compared to previous studies, improved survival in emergent cases was noted. Further studies with long-term follow-up are needed to determine if enteropathy-related signs persist after cholecystectomy.

Comparison of fibroblast growth factor 19 concentrations between dogs with and without gallbladder mucoceles

BACKGROUND

Fibroblast growth factor 19 (FGF19) is an enterohepatic hormone the synthesis of which is stimulated by bile acid activation of the nuclear farnesoid X receptor (FXR) in ileal enterocytes. Increased production of FGF19 downregulates hepatocyte bile acid synthesis and gluconeogenesis, while concurrently upregulating hepatocyte glycogenesis and gallbladder (GB) filling. The physiologic impact of this regulatory cycle is illustrated in cholecystectomized humans, in whom the disturbed meal-related flux of GB bile decreases serum FGF19 concentrations.

OBJECTIVE

Determine if serum FGF19 concentrations are lower in dogs with clinical GB mucoceles (GBMs) than in control dogs.

ANIMALS

Seven dogs with GBM diagnosed using abdominal ultrasonography, biochemical markers, and GB histopathology. Forty-two control dogs without gastrointestinal or hepatobiliary disorders also were evaluated. Health status of controls was assessed by physical examination and diagnostic hematologic and biochemical test results.

METHODS

Prospective cross-sectional study to compare fasting plasma or serum FGF19 concentrations between groups. Concentrations of FGF19 were quantified by a commercially available FGF19 ELISA.

RESULTS

Concentrations of FGF19 were significantly lower in dogs with clinical GBM (median, 14.0 pg/mL; range, 12.8-67.2) than in control dogs (median, 145.3 pg/mL; range, 36.5-285.1).

CONCLUSIONS AND CLINICAL IMPORTANCE

In dogs, GBM is associated with significantly decreased serum FGF19 concentrations. We speculate that this finding reflects compromised GB contraction and decreased enterohepatic circulation of bile flow. Subnormal FGF19 concentrations may influence bile acid synthesis and hepatic metabolism.

Characteristics of gallbladder microbiome in healthy dogs and cats, dogs with gallbladder mucocele, and cats with suspected cholangitis/cholangiohepatitis

The aim of this study was to investigate and characterize the microbiome in bile samples obtained from dogs with gallbladder mucocele (6), cats with suspected cholangitis/cholangiohepatitis (4), as well as from healthy dogs (6) and cats (4). Our goal was to compare the microbiome patterns with clinical findings and bacterial culture results in diseases of the gallbladder and to identify a potential microbial biomarker of diseased groups. The microbial taxa composition revealed that Proteobacteria were the most dominant phylum in healthy and diseased individuals in all groups. Individuals from six families including Burkholderiaceae, Phyllobacteriaceae, Bradyrhizobiaceae, Sphingomonadaceae, Moraxellaceae, and Caulobacteraceae, constituted the core microbiome in the gallbladder of healthy dogs. A combination of LEfSe analysis and Taxa2ASV decomposer revealed that Pseudomonaceae and Ruminococcaceae exclusively occurred in the mucocele group. In conclusion, this study determined the core microbiome in the gallbladder of healthy dogs and the possible biomarkers (Pseudomonaceae and Ruminococcaceae) of gallbladder mucocele in dogs.

Canine Gallbladder Erosion/Ulcer and Hemocholecyst: Clinicopathological Characteristics of 14 Cases

(1) Background: Gallbladder mucosal erosion and/or ulceration are illnesses associated with unexpected gallbladder intra-cystic bleeding (hemocholecyst), an under-reported problem in dogs. (2) Methods: Clinicopathological characteristics of 14 dogs with gallbladder erosion/ulcer were investigated in this single-center retrospective study using clinical data and archived gallbladder tissues of client-owned dogs. (3) Results: Canine gallbladder erosion/ulcer tends to occur in older, neutered dogs of various breeds. Vomiting, lethargy, and anorexia are common. Concurrent gallbladder rupture occurred in 5/14 cases (35.7%), while rupture was absent in 6/14 cases (42.8%) and undetermined in 3/14 (21.4%) cases. Histologically, the gallbladder wall was markedly thickened due to mucosal hyperplasia, inflammatory infiltrates, fibrosis, edema, hemorrhage, and smooth muscle hyperplasia/hypertrophy. Twelve out of fourteen cases (85.7%) had concurrent cholecystitis of varying severity. Bacteria were detected by Giemsa or Warthin-Starry stain in 8/14 (57.1%) cases. Bacterial rods immunoreactive to the anti-Helicobacter antibody were present in one case. Mucosal epithelial cells of the gallbladder erosion/ulcer cohort were immunopositive for the cyclooxygenases COX-1 or COX-2 in only 5/14 (35.7%) cases. In contrast, COX-1 and COX-2 were more frequently expressed in a reference pool of cases of gallbladder mucocele (n = 5) and chronic cholecystitis (n = 5). COX-1 was expressed in 9/10 cases (90.0%) of gallbladder mucocele and chronic cholecystitis and in 10/10 cases (100%) for COX-2. (4) Conclusions: Canine gallbladder erosion/ulcer is an under-reported condition which requires active clinical intervention. Based on the clinicopathological information reported in this study in addition to the COX-1 and COX-2 IHC results, we suggest that canine gallbladder erosion/ulcer may be related to decreased cytoprotection physiologically provided by arachidonic acid, but which is decreased or absent due to reduced COX expression because of yet undetermined etiologies.

High frequency of cholecystitis in dogs with gallbladder mucocoele in Hong Kong

The aims of this retrospective study were to characterise the epidemiological, clinical, histopathological, and microbiological findings as well as surgical outcomes in dogs admitted to a specialist veterinary hospital in Hong Kong for surgical management of gallbladder mucocoele (GBM). Inclusion criteria were cases with histopathological diagnosis of GBM and accompanying abdominal imaging, serum biochemistry, bile culture, and liver biopsy histology results. Fifty-six cases met the inclusion criteria. The median age at diagnosis was 12 years (range, 5-16 years). Miniature or toy pure-breed dogs were most commonly affected, including Poodles, Pomeranians, Schnauzers, Bichon frises and Chihuahuas. However, no breed was over-represented compared with their expected proportions among annual hospital admissions. Histological evidence of cholecystitis was present in 84% of cases, including acute cholecystitis in 18%, chronic cholecystitis in 37.5%, acute on chronic cholecystitis in 28% and acute with necrosis in 6%. The most common liver lesions were cholestasis in 64%, along with portal fibrosis in 55%, oedema in 50% and bile duct hyperplasia in 50%. Bile culture was positive in 29.6% of cases. Escherichia coli and Enterobacter species were most commonly isolated. Stentrophomonas maltophili was cultured from one case. Of the 16 cases where bacteria were isolated from bile culture, 94% had evidence of chronic cholecystitis and 81% had evidence of cholangiohepatitis. Fifty dogs (89.3%) survived to discharge including 5/5 dogs with ruptured gallbladders. Of 34 dogs with follow-up data, 21/34 (61.8%) were still alive 12 months later. Gallbladder mucocoeles were frequently associated with both acute and chronic inflammation. High survival rates to discharge were achieved.

Multidrug resistant Enterococcus faecium isolate from cholangitis/cholecystitis in a dog

Mucocele and cholecystitis were diagnosed in a 10 year-old Shetland-sheepdog presenting aspecific clinical signs. Blood examinations and ultrasonography investigation were performed before to surgical approach, which allowed to collect biopsies and samples for bacteriological analyses. In addition, the patient was subjected to cholecystectomy. A multidrug resistant Enterococcus faecium was isolated from the gallbladder specimens. On the basis of antimicrobial susceptibility test, nitrofurantoin was used. The correct bacteriological diagnosis is necessary to set up effective therapy, influencing the patient's prognosis and improving the recovery time.

A multicenter retrospective study assessing progression of biliary sludge in dogs using ultrasonography

Background

Objectives

Animals

Methods

Results

Conclusions and Clinical Importance

Canine extrahepatic biliary disease: what have we learned?

Extrahepatic biliary disease in dogs is commonly encountered in clinical practice worldwide. Diseases in this segment of the biliary tract are diverse and can manifest with mild clinical signs or can be life-threatening. In the last decade there have been advances in diagnostic tests, imaging modalities and therapeutic interventions as well as the identification of novel prognostic variables that could improve outcomes in dogs with extrahepatic biliary disease. Therefore, the objective of this review was to summarise clinically relevant updates of extrahepatic biliary disease in dogs.

Chronic Cholecystitis of Dogs: Clinicopathologic Features and Relationship with Liver

Simple Summary

This study on the gallbladders and livers of 219 client-owned dogs provides a benchmark for future studies on chronic canine cholecystitis. The statistical evaluation of clinical data; histopathology; histochemistry; and immunohistochemistry in this report provides insight into the etiology of chronic cholecystitis in dogs

Abstract

(1) Background: Chronic cholecystitis of dogs has not been vigorously investigated histopathologically. In addition, the relationship between gallbladder and liver diseases is not known. (2) Methods: We aimed to provide a hallmark for canine chronic cholecystitis using clinical data, histopathology, histochemistry, immunohistochemistry, and statistical analysis. (3) Results: Our investigation of 219 ultrasonographically abnormal surgically resected canine gallbladders revealed 189 cases (86.3%) of mucosal lymphoplasmacytic infiltration (chronic cholecystitis). Sludge, a gravity-dependent or nondependent fine granular hyperechoic material, was more prevalent (105/219, 47.9%) than mucocele (51/219, 23.2%) in this cohort. Mucosal lymphoid follicles were detected in 68/219 cases (31%), suggesting the influence of long-standing antigenic stimulation. Bacteria were histochemically detected in 41/60 (68.3%) of heavily inflamed gallbladders, 18/129 (14%) of lightly inflamed, and 3/18 (16.7%) of uninflamed gallbladders, suggesting a possible relationship between bacteria and chronic cholecystitis. Simultaneous liver biopsies revealed mild or no inflammation, changes consistent with primary portal vein hypoplasia, and mild hepatocellular degeneration. (4) Conclusions: Based on the results of our statistical analysis, we conclude that canine chronic cholecystitis is a long-standing inflammatory process of unknown (but possibly bacterial) etiology and that liver pathology is unlikely the cause of chronic cholecystitis in dogs.

Acute Hepatopathy in a Dog Secondary to Hypothyroidism-Induced Atherosclerotic Infarction and Necrosis

A 7 yr old male beagle was examined because of lethargy, anorexia, and cranial abdominal discomfort. Significant clinicopathologic abnormalities included severe liver enzyme elevations and hypercholesterolemia. Abdominal imaging identified vascular compromise of the left lateral liver lobe and a gallbladder mucocele. Following liver lobectomy and cholecystectomy, the dog's clinical signs resolved, and liver enzymes substantially improved. Diffuse hepatocellular infarction and necrosis secondary to multifocal atherosclerosis was present on histopathology of the liver. Hypothyroidism was subsequently diagnosed. Restoration of euthyroidism with oral levothyroxine therapy resolved the remaining liver enzyme elevations and hypercholesterolemia. To the author's knowledge, this is the first case report of hypothyroidism resulting in a clinically apparent and resolvable acute hepatopathy due to atherosclerosis. Clinicians should include atherosclerosis as a differential diagnosis for dogs with an acute hepatopathy and investigate dogs for hypothyroidism if atherosclerosis is diagnosed on liver biopsy.

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND): Nonproliferative and Proliferative Lesions of the Dog

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions) Project (www.toxpath.org/inhand.asp) is a joint initiative of the societies of toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP), and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying lesions observed in most tissues and organs from the dog used in nonclinical safety studies. Some of the lesions are illustrated by color photomicrographs. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions, lesions induced by exposure to test materials, and relevant infectious and parasitic lesions. A widely accepted and utilized international harmonization of nomenclature for lesions in laboratory animals will provide a common language among regulatory and scientific research organizations in different countries and increase and enrich international exchanges of information among toxicologists and pathologists.

Influence of normograde versus retrograde catheterization of bile ducts in dogs treated for gallbladder mucocele

OBJECTIVE

To determine the influence of normograde (NG) versus retrograde (RG) catheterization of the cystic duct and common bile duct (CBD) in dogs with gallbladder mucoceles (GBM) treated with open cholecystectomy.

STUDY DESIGN

Retrospective study.

ANIMALS

Dogs (n = 117) with GBM.

METHODS

Medical records were reviewed for signalment, history, clinical laboratory and diagnostic imaging findings, details of surgery including catheterization method, complications, and outcome. Long-term follow-up data were obtained by telephone or electronic communication. Relationships between catheterization method and clinical variables and outcome were evaluated.

RESULTS

Dogs catheterized RG were more likely to experience any postoperative complication (p = .0004) including persistence of gastrointestinal signs (p = .0003). Survival to discharge and long-term survival did not differ by group (p = .23 and p = .49). Total bilirubin (TB) decreased by 70.3% after NG catheterization compared to 39.1% after RG catheterization (p = .03) and increased in 14.9% dogs catheterized NG and 38.0% dogs catheterized RG (p = .004). The presence of a diplomate surgeon at surgery resulted in decreased incidences of any perioperative or postoperative complication (p = .003 and p = .05).

CONCLUSION

Retrograde catheterization was associated with more postoperative concerns than NG catheterization, but similar survival times. Surgery should be performed by diplomates experienced in biliary surgery to minimize complications.

CLINICAL SIGNIFICANCE

Although both NG and RG techniques to catheterize the cystic duct and CBD are options for treatment of GBM with low mortality, results of this study provide some evidence to recommend NG over RG catheterization.

Clinical characteristics and histology of cholecystectomised dogs with nongravity-dependent biliary sludge: 16 cases (2014-2019)

OBJECTIVES

To report the available histology, biochemistry and clinical progression of dogs without classic overt biliary tract signs that underwent cholecystectomy for nongravity-dependent biliary sludge.

MATERIALS AND METHODS

Case series of client-owned dogs for which a cholecystectomy was performed for nongravity-dependent biliary sludge. In six dogs, for which nongravity-dependent biliary sludge filled less than half of gall bladder volume, gall bladder ejection fractions were measured. Available histology, biochemistry, presenting clinical signs and post-surgical clinical progression were reported.

RESULTS

Sixteen dogs were included in this retrospective case series. No dogs met the histological criteria for gall bladder mucocoeles or had histological evidence of primary hepatitis or cholangitis. Biochemistry was normal for 11 dogs. Hypercholesterolaemia was not noted in any dog. Twelve dogs had cholecystitis (11 lymphoplasmacytic, one neutrophilic) and nine dogs had biliary mucosal hyperplasia. Thirteen dogs had enteritis (12 lymphoplasmacytic, one eosinophilic) and nine dogs had reactive hepatitis (eight lymphoplasmacytic, one neutrophilic). All six dogs with nongravity-dependent biliary sludge that filled less than half of gall bladder volume had sub-optimal gall bladder function. Presenting clinical signs, including diurnal inappetence in the morning and exercise intolerance, resolved in 86% (12/14) of dogs after cholecystectomy and clinical improvement was noted in 81% (13/16) of dogs overall.

CLINICAL SIGNIFICANCE

Duodenal inflammation could potentially impact gall bladder dysmotility in dogs with nongravity-dependent biliary sludge. Furthermore, diurnal inappetence in the morning and exercise intolerance could indicate symptomatic gall bladder disease in dogs with NDBS and can potentially precede more obvious systemic clinical signs associated with gall bladder mucocoeles.

Serological markers of gluten sensitivity in Border terriers with gall bladder mucocoeles

OBJECTIVES

To evaluate serological markers of gluten sensitivity in conjunction with cholecystokinin measurement in Border terriers with gall bladder mucocoeles.

MATERIALS AND METHODS

Medical records from two referral hospitals were obtained between 2011 and 2019 to identify Border terriers with gall bladder mucocoeles, non-Border terriers with gall bladder mucocoeles and control Border terriers with non-biliary diseases. Enzyme-linked immunosorbent assays were performed on stored fasted serum samples for anti-gliadin IgG, anti-canine transglutaminase-2-IgA autoantibodies and cholecystokinin. Statistical analysis was performed using the Kruskall-Wallis test to identify differences between the groups.

RESULTS

Fifteen Border terriers with gall bladder mucocoeles, 17 non-Border terriers with gall bladder mucocoeles and 14 control Border terriers with non-biliary diseases were recruited. Median transglutaminase-2-IgA autoantibodies in Border terriers with gall bladder mucocoeles was 0.73 (range: 0.18 to 1.67), which was significantly greater than in control Border terriers at 0.41 (0.07 to 1.14). Median cholecystokinin concentration in Border terriers with gall bladder mucocoeles was 13 pg/mL (6 to 45 pg/mL), which was significantly lower than in control Border terriers at 103 pg/mL (9 to 397 pg/mL). There was no difference in the anti-gliadin IgG between these groups. There was no difference observed in the non-Border terriers with gall bladder mucocoeles with either of the other groups.

CLINICAL SIGNIFICANCE

Reduced cholecystokinin and increased transglutaminase-2-IgA autoantibodies was detected in Border terriers with gall bladder mucocoeles; which is in part homologous to gall bladder disease identified in human coeliac disease. The results suggest an immunological disease with impaired cholecystokinin release may be affecting gall bladder motility and possibly contributing to mucocoele formation in Border terriers.

Impact of intra-operative hypotension on mortality rates and post-operative complications in dogs undergoing cholecystectomy

OBJECTIVES

To report the mortality rate within a cohort of dogs undergoing cholecystectomy and investigate the impact of intra-operative hypotension on mortality.

MATERIALS AND METHODS

Clinical records at five UK referral centres were reviewed for dogs undergoing cholecystectomy. Data collected included presenting signs, pre-operative blood test results, intra-operative data including frequency and duration of hypotension and the incidence and type of post-operative complications.

RESULTS

Data from 119 dogs were included. Sixteen dogs (13%) died before discharge and by 28 days after surgery the total mortality was 19 dogs (17%). Hypotension lasting over 10 minutes during general anaesthesia occurred in 65 dogs (54.6%), with a mean ± sd duration of 36.1 ± 30.0 minutes. Intra-operative hypotension or the number of hypotensive episodes did not appear to be associated with in-hospital or 28-day mortality. American Society of Anaesthesiologists grade (of fitness for surgery) was significantly associated with both in-hospital and 28-day mortality on univariable analysis, as were post-operative hypoproteinaemia, ileus and pancreatitis. However on multivariable analysis, only ileus and pancreatitis were found to significantly impact mortality.

CLINICAL SIGNIFICANCE

Dogs presenting with a higher American Society of Anaesthesiologists grade appear to have a higher risk of mortality, although intra-operative hypotension did not appear to be part of this risk.

Prevalence and impact of cholecystitis on outcome in dogs with gallbladder mucocele

BACKGROUND

Gallbladder mucocele is a potentially life-threatening extrahepatic biliary disease in dogs. The primary aims of this study were to evaluate the prevalence of cholecystitis in dogs with gross and histopathologically confirmed gallbladder mucocele and to investigate if there is an association between cholecystitis, including its subtypes (eg, acute, acute on chronic, with necrosis, chronic), and survival. Our secondary objective was to evaluate if there is an association between cholecystitis and intraoperative bacteriological culture positivity.

KEY FINDINGS

Two hundred nineteen dogs with gallbladder mucocele were included in this multi-institutional retrospective study, of which 63 (28.8%) dogs had histopathological evidence of cholecystitis. The most common forms of cholecystitis were acute on chronic (n = 22/63, 34.9%) and with necrosis (n = 20, 31.7%). Thirty-one (14.1%) dogs had growth of at least 1 bacterial isolate; however, 88.7% had antimicrobials administered within the 48 hours before surgery or intraoperatively. There was not an association between cholecystitis or its subtypes and survival. Furthermore, there was not an association between cholecystitis and intraoperative bacteriological culture positivity. A total of 38 (17.4%) dogs either died or were euthanized during hospitalization.

SIGNIFICANCE

Cholecystitis is a common comorbidity in dogs with gallbladder mucocele but was not associated with decreased survival.

Long-term survival of dogs treated for gallbladder mucocele by cholecystectomy, medical management, or both

BACKGROUND

Gallbladder mucoceles (GBM) typically are treated by cholecystectomy. Medical management rarely has been reported and medical and surgical management have not been compared.

HYPOTHESIS/OBJECTIVES

To compare survival of dogs treated for GBM by medical management or cholecystectomy or both.

ANIMALS

Eighty-nine client-owned dogs diagnosed with GBM that received cholecystectomy or medical treatment or both from 2011 to 2017.

METHODS

Potential cases were identified by searching the medical records database. Data collected included signalment, clinicopathologic results, treatments, and ultrasonographic images and reports. Dogs were grouped according to the treatment received (medical management, surgical treatment, or both) that was chosen at the discretion of the attending veterinarian. Survival analysis was performed and prognostic variables identified and compared between treatment groups.

RESULTS

Of dogs surviving at least 14 days after diagnosis, median survival times were 1802 (95% confidence interval [CI], 855-not reached) days, 1340 (95% CI, 444-1340) days, and 203 (95% CI, 18-525) days, for the surgical, medical, and medical then surgical treatment groups, respectively, and differed significantly (P < .0001). Gallbladder mucocele type (P = .05), serum alkaline phosphatase activity (P = .0001), and serum creatinine (P = .002) and phosphorus (P = .04) concentrations were associated with decreased survival across groups. Suspicion of biliary rupture on abdominal ultrasound (AUS) examination was correlated with increased survival in the surgical group (P = .02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Cholecystectomy for the treatment of GBM results in the best long-term survival in dogs surviving the immediate postoperative period (14 days) compared to medical management. Although medical management is associated with shorter survival compared to surgical treatment, it is a reasonable alternative when surgery cannot be pursued.

Effect of clinical signs, endocrinopathies, timing of surgery, hyperlipidemia, and hyperbilirubinemia on outcome in dogs with gallbladder mucocele

Gallbladder mucocele (GBM) is a common extra-hepatic biliary syndrome in dogs with death rates ranging from 7 to 45%. Therefore, the aim of this study was to identify the association of survival with variables that could be utilized to improve clinical decisions. A total of 1194 dogs with a gross and histopathological diagnosis of GBM were included from 41 veterinary referral hospitals in this retrospective study. Dogs with GBM that demonstrated abnormal clinical signs had significantly greater odds of death than subclinical dogs in a univariable analysis (OR, 4.2; 95% CI, 2.14-8.23; P<0.001). The multivariable model indicated that categorical variables including owner recognition of jaundice (OR, 2.12; 95% CI, 1.19-3.77; P=0.011), concurrent hyperadrenocorticism (OR 1.94; 95% CI, 1.08-3.47; P=0.026), and Pomeranian breed (OR, 2.46; 95% CI 1.10-5.50; P=0.029) were associated with increased odds of death, and vomiting was associated with decreased odds of death (OR, 0.48; 95% CI, 0.30-0.72; P=0.001). Continuous variables in the multivariable model, total serum/plasma bilirubin concentration (OR, 1.03; 95% CI, 1.01-1.04; P<0.001) and age (OR, 1.17; 95% CI, 1.08-1.26; P<0.001), were associated with increased odds of death. The clinical utility of total serum/plasma bilirubin concentration as a biomarker to predict death was poor with a sensitivity of 0.61 (95% CI, 0.54-0.69) and a specificity of 0.63 (95% CI, 0.59-0.66). This study identified several prognostic variables in dogs with GBM including total serum/plasma bilirubin concentration, age, clinical signs, concurrent hyperadrenocorticism, and the Pomeranian breed. The presence of hypothyroidism or diabetes mellitus did not impact outcome in this study.

Investigation of adrenal and thyroid gland dysfunction in dogs with ultrasonographic diagnosis of gallbladder mucocele formation

Gallbladder mucocele formation is an emerging disease in dogs characterized by increased secretion of condensed granules of gel-forming mucin by the gallbladder epithelium and formation of an abnormally thick mucus that can culminate in obstruction of the bile duct or rupture of the gallbladder. The disease is associated with a high morbidity and mortality and its pathogenesis is unknown. Affected dogs have a significantly increased likelihood of concurrent diagnosis of hyperadrenocorticism, hypothyroidism, and hyperlipidemia. Whether these endocrinopathies represent coincidental primary disease processes that exacerbate gallbladder mucocele formation in predisposed dogs or reflect a concurrent disruption of endocrine and lipid metabolism is unclear. In this study, we investigated a hypothesis that dogs with gallbladder mucocele formation would have a high prevalence of occult and atypical abnormalities in adrenal cortical and thyroid gland function that would suggest the presence of endocrine disruption and provide deeper insight into disease pathogenesis. We performed a case-control study of dogs with and without ultrasonographic diagnosis of gallbladder mucocele formation and profiled adrenal cortical function using a quantitative mass spectrometry-based assay of serum adrenal-origin steroids before and after administration of synthetic cosyntropin. We simultaneously profiled serum thyroid hormone concentrations and evaluated iodine sufficiency by measurement of urine iodine:creatinine ratios (UICR). The studies were complemented by histological examination of archival thyroid tissue and measurements of thyroid gland organic iodine from dogs with gallbladder mucocele formation and control dogs. Dogs with gallbladder mucocele formation demonstrated an exaggerated cortisol response to adrenal stimulation with cosyntropin. A prevalence of 10% of dogs with gallbladder mucocele formation met laboratory-based criteria for suspect or definitive diagnosis of hyperadrenocorticism. A significantly greater number of dogs with gallbladder mucocele formation had basal serum dehydroepiandrosterone (DHEAS) increases compared to control dogs. A high percentage of dogs with gallbladder mucocele formation (26%) met laboratory-based criteria for diagnosis of hypothyroidism, but lacked detection of anti-thyroglobulin antibodies. Dogs with gallbladder mucocele formation had significantly higher UICRs than control dogs. Examination of thyroid tissue from an unrelated group of dogs with gallbladder mucocele formation did not demonstrate histological evidence of thyroiditis or significant differences in content of organic iodine. These findings suggest that dogs with gallbladder mucocele formation have a greater capacity for cortisol synthesis and pinpoint DHEAS elevations as a potential clue to the underlying pathogenesis of the disease. A high prevalence of thyroid dysfunction with absent evidence for autoimmune thyroiditis suggest a disrupted thyroid hormone metabolism in dogs with gallbladder mucocele formation although an influence of non-thyroidal illness cannot be excluded. High UICR in dogs with gallbladder mucocele formation is of undetermined significance, but of interest for further study.

In vitro effect of 20% N-acetylcysteine on the viscosity of normal canine bile

OBJECTIVE To evaluate the in vitro effect of 20% N-acetylcysteine (NAC) on the viscosity of normal canine bile. ANIMALS Bile samples obtained from 10 adult dogs euthanized for reasons unrelated to biliary disease. PROCEDURES Each sample was centrifuged to remove particulates, then divided into 3 aliquots. One aliquot remained untreated (control). Each of the other aliquots was diluted 1:4 with 20% NAC or sterile water. The viscosity of all samples was measured with a rotational viscometer at 25°C. Viscosity of control samples was measured immediately after centrifugation and at 1 and 24 hours after treatment application to the diluted samples. Viscosity of diluted samples was measured at 1 and 24 hours after treatment application. RESULTS Mean viscosity differed significantly among the 3 groups at both 1 and 24 hours after treatment application. Relative to control samples, the addition of NAC and sterile water decreased the viscosity by approximately 3.35 mPa·s (95% confidence interval [CI], 1.58 to 5.12 mPa·s) and 2.74 mPa·s (95% CI, 1.33 to 4.14 mPa·s), respectively. Mean viscosity of the NAC-treated samples was approximately 0.61 mPa·s (95% CI, 0.21 to 1.01 mPa·s) less than that for the sterile water-treated samples. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that in vitro dilution of canine bile 1:4 with 20% NAC significantly decreased the viscosity of the resulting mixture. Further research is necessary to determine whether NAC is a safe and effective noninvasive treatment for dogs with persistent biliary sludge or gallbladder mucoceles.

Non-target toxicity of novel insecticides

Humans have used insecticides since ancient times. The spectrum and potency of available insecticidal substances has greatly expanded since the industrial revolution, resulting in widespread use and unforeseen levels of synthetic chemicals in the environment. Concerns about the toxic effects of these new chemicals on non-target species became public soon after their appearance, which eventually led to the restrictions of use. At the same time, new, more environmentally-friendly insecticides have been developed, based on naturally occurring chemicals, such as pyrethroids (derivatives of pyrethrin), neonicotinoids (derivatives of nicotine), and insecticides based on the neem tree vegetable oil (Azadirachta indica), predominantly azadirachtin. Although these new substances are more selective toward pest insects, they can still target other organisms. Neonicotinoids, for example, have been implicated in the decline of the bee population worldwide. This review summarises recent literature published on non-target toxicity of neonicotinoids, pyrethroids, and neem-based insecticidal substances, with a special emphasis on neonicotinoid toxicity in honeybees. We also touch upon the effects of pesticide combinations and documented human exposure to these substances.

Effect of prednisolone administration on gallbladder emptying rate and gallbladder bile composition in dogs

OBJECTIVE To investigate effects of prednisolone administration on gallbladder emptying rate and gallbladder bile composition in dogs. ANIMALS 6 healthy Beagles. PROCEDURES Prednisolone was administered (2 mg/kg, SC, once daily for 2 weeks) to each dog and tapered over 2 weeks. Gallbladder emptying rate and bile composition were evaluated before and after administration of prednisolone for 2 weeks as well as 1 week after cessation of prednisolone administration. RESULTS Gallbladder emptying rate decreased significantly after prednisolone administration (median, 27%; range, 0% to 38%), compared with rate before administration (median, 59%; range, 29% to 68%), but then increased 1 week after cessation of administration (median, 45%; range, 23% to 48%). Gallbladder bile mucin concentration decreased significantly after prednisolone administration (median, 8.8 mg/dL; range, 6.2 to 11.3 mg/dL), compared with concentration before administration (median, 13.1 mg/dL; range, 10.7 to 21.7 mg/dL), but then increased 1 week after cessation of administration (median, 14.3 mg/dL; range, 9.6 to 26.7 mg/dL). Gallbladder taurochenodeoxycholic acid concentration decreased significantly after prednisolone administration (8.1 mmol/L; range, 6.8 to 15.2 mmol/L), compared with concentration before administration (median, 27.2 mmol/L; range, 22.0 to 31.9 mmol/L), but then increased 1 week after cessation of administration (median, 26.4 mmol/L; range, 15.1 to 31.5 mmol/L). CONCLUSIONS AND CLINICAL RELEVANCE A lower gallbladder emptying rate caused by prednisolone administration may be involved in the pathogenesis of gallbladder disease in dogs. Further studies are required to determine the clinical importance of lower gallbladder bile mucin concentrations caused by glucocorticoid administration in the pathogenesis of gallbladder disease in dogs.

Gall bladder mucoceles in Border terriers

Background

Gall bladder mucoceles (GBM) are a leading cause of biliary disease in dogs with several breeds, including the Shetland Sheepdog, American Cocker Spaniel, Chihuahua, Pomeranian, and Miniature Schnauzer apparently predisposed.

Objective

To determine risk factors, clinical features, and response to treatment of GBM in Border terriers (BT).

Animals

Medical records of 99 dogs (including 51 BT) with an ultrasonographic (±histopathologic) diagnosis of GBM from three referral centers in the United Kingdom were collected. A control group of 87 similar‐aged BT with no ultrasonographic evidence of gall bladder disease was selected for comparison.

Method

Retrospective case‐control study. Odds ratios were calculated to establish breed predisposition. Signalment, presence of endocrine disease, clinicopathologic results, and outcome were compared between the BT, other breeds, and control BTs.

Results

The odds of identifying a GBM in a BT in this hospital population was 85 times that of all other breeds (95% confidence interval 56.9‐126.8). BT had similar clinical signs and clinicopathologic changes to other breeds with GBM. There was no evidence that endocrinopathies were associated with GBM in BT.

Clinical Significance

A robust breed predisposition to GBM is established for the BT.

Effect of a high-fat-high-cholesterol diet on gallbladder bile acid composition and gallbladder motility in dogs

OBJCTIVE To investigate the effects of dietary lipid overload on bile acid metabolism and gallbladder motility in healthy dogs. ANIMALS 7 healthy Beagles. PROCEDURES In a crossover study, dogs were fed a high-fat-high-cholesterol diet (HFCD) or a low-fat diet (LFD) for a period of 2 weeks. After a 4-month washout period, dogs were fed the other diet for 2 weeks. Before and at the end of each feeding period, the concentrations of each of the gallbladder bile acids, cholecystokinin (CCK)-induced gallbladder motility, and bile acid metabolism-related hepatic gene expression were examined in all dogs. RESULTS The HFCD significantly increased plasma total cholesterol concentrations. The HFCD also increased the concentration of taurochenodeoxycholic acid and decreased the concentration of taurocholic acid in bile and reduced gallbladder contractility, whereas the LFD significantly decreased the concentration of taurodeoxycholic acid in bile. Gene expression analysis revealed significant elevation of cholesterol 7α-hydroxylase mRNA expression after feeding the HFCD for 2 weeks, but the expression of other genes was unchanged. CONCLUSIONS AND CLINICAL RELEVANCE Feeding the HFCD and LFD for 2 weeks induced changes in gallbladder bile acid composition and gallbladder motility in dogs. In particular, feeding the HFCD caused an increase in plasma total cholesterol concentration, an increase of hydrophobic bile acid concentration in bile, and a decrease in gallbladder sensitivity to CCK. These results suggested that similar bile acid compositional changes and gallbladder hypomotility might be evident in dogs with hyperlipidemia.

Qualitative metabolomics profiling of serum and bile from dogs with gallbladder mucocele formation

Mucocele formation is characterized by secretion of abnormally thick mucus by the gallbladder epithelium of dogs that may cause obstruction of the bile duct or rupture of the gallbladder. The disease is increasingly recognized and is associated with a high morbidity and mortality. The cause of gallbladder mucocele formation in dogs is unknown. There is a strong breed predisposition and affected dogs have a high incidence of concurrent endocrinopathy or hyperlipidemia. These observations suggest a significant influence of both genetic and metabolic factors on disease pathogenesis. In this study, we investigated a theory that mucocele formation is associated with a syndrome of metabolic disruption. We surmised that a global, untargeted metabolomics approach could provide unique insight into the systemic pathogenesis of gallbladder mucocele formation and identify specific compounds as candidate biomarkers or treatment targets. Moreover, concurrent examination of the serum and hepatic duct bile metabolome would enable the construction of mechanism-based theories or identification of specific compounds responsible for altered function of the gallbladder epithelium. Abnormalities observed in dogs with gallbladder mucocele formation, including a 33-fold decrease in serum adenosine 5’-monophosphate (AMP), lower quantities of precursors required for synthesis of energy transporting nucleotides, and increases in citric acid cycle intermediates, suggest excess metabolic energy and a carbon surplus. Altered quantities of compounds involved in protein translation and RNA turnover, together with accumulation of gamma-glutamylated and N-acetylated amino acids in serum suggest abnormal regulation of protein and amino acid metabolism. Increases in lathosterol and 7α-hydroxycholesterol suggest a primary increase in cholesterol synthesis and diversion to bile acid formation. A number of specific biomarker compounds were identified for their ability to distinguish between control dogs and those that formed a gallbladder mucocele. Particularly noteworthy was a significant decrease in quantity of biologically active compounds that stimulate biliary ductal fluid secretion including adenosine, cAMP, taurolithocholic acid, and taurocholic acid. These findings support the presence of significant metabolic disruption in dogs with mucocele formation. A targeted, quantitative analysis of the identified serum biomarkers is warranted to determine their utility for diagnosis of this disease. Finally, repletion of compounds whose biological activity normally promotes biliary ductal secretion should be examined for any therapeutic impact for resolution or prevention of mucocele formation.

Spontaneous Course of Biliary Sludge Over 12 Months in Dogs with Ultrasonographically Identified Biliary Sludge

Background

Biliary sludge is associated with gallbladder (GB) dysmotility and mucus hypersecretion suggesting a link between biliary sludge and the formation of GB mucoceles (GBM). If biliary sludge progresses to GBM, treatment to reduce the production and progression of sludge is warranted.

Hypothesis/Objectives

The objective of this study was to determine the course of biliary sludge in dogs.

Animals

Seventy‐seven healthy, client‐owned dogs ≥4 years of age screened for biliary sludge; 45 affected dogs identified.

Methods

Prospective, observational design. Serial ultrasound examinations were evaluated at 3, 6, 9, and 12 months to monitor degree of sludge based on proportion of GB filled with sludge (mild [0.01–24.4%], moderate [24.5–49.4%], moderate to severe [49.5–74.4%], severe [74.5–100%]), gravity dependency of sludge, and GB dimensions.

Results

After 1 year of follow‐up, the degree of sludge was mild (34%), moderate (47%), moderate to severe (13%), severe (3%), or absent (3%). There was no significant difference in median degree of sludge over 1 year (P = .36). There were no significant changes in the gravity dependency of sludge over 1 year. A subset of dogs, 24%, with initial gravity‐dependent sludge developed a combination of nondependent and dependent sludge. Dogs had resolved (2%), decreased (19%), static (40%), increased (29%), or recurrent (10%) sludge at the conclusion of the study.

Conclusions and Clinical Importance

Biliary sludge was prevalent, affected dogs remained asymptomatic, and it rarely resolves in healthy dogs over a period of 1 year. Some dogs developed nongravity‐dependent sludge within 1 year, which might indicate changes in consistency of sludge.