Percutaneous ultrasound-guided cholecystocentesis: complications and association of ultrasonographic findings with bile culture results

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.

Cytologic Evaluation of the Liver

Liver fine needle aspiration (FNA) and bile cytology are valuable diagnostic tools for evaluating various hepatobiliary diseases in veterinary medicine. Although FNA of the liver is less invasive and faster than histopathology, it may not always provide a definitive diagnosis, but will often provide information regarding pathologic processes occurring in the liver. Cytologic evaluation is most effective when integrated with clinical information including bloodwork, imaging, and results of other diagnostic tests.

Ultrasonographic features of gallbladder wall thickening in dogs with hypoalbuminemia

Hypoalbuminemia has been considered as a cause of gallbladder wall thickening in humans and dogs. Recent study revealed that gallbladder wall thickening in dogs with hypoalbuminemia may not be associated with serum albumin/plasma levels within 48 h of ultrasound study. However, gallbladder wall edema may change within 48 h, and the ultrasonographic features of gallbladder wall thickening in dogs with hypoalbuminemia have not been reported. The purpose of this study is to describe the relationship between serum albumin levels within 24 h of ultrasound and gallbladder wall thickening, and to describe the ultrasonographic features of thickened gallbladder walls in dogs with hypoalbuminemia. 37 hypoalbuminemic dogs with gallbladder ultrasound images were retrospectively included. Ultrasound studies were reviewed, and gallbladder wall thickness, layering appearance, echogenicity, echotexture, distribution, evidence of gallbladder mucocele, and presence of peritoneal effusion were recorded. Additionally, serum albumin levels within 24 h of ultrasound study and the administerd sedation were recorded. The prevalence of gallbladder wall thickening in dogs with hypoalbuminemia was 13.5%. The 3-layer appearance of the gallbladder wall was observed in 4 dogs, and a single-layer gallbladder wall thickening in one dog. Diffuse thickening was observed in all 5 dogs. The serum albumin level of dogs with gallbladder wall thickening was not different (p = 0.14) from dogs without thickening. Gallbladder wall thickening was not common, occurring only with mild hypoalbuminemia, and was commonly associated with a 3-layer appearance and considered as gallbladder wall subserosal edema. Causes other than hypoalbuminemia may be responsible for thickening of the gallbladder wall in dogs with hypoalbuminemia.

Microbiome analysis of bile from apparently healthy cats and cats with suspected hepatobiliary disease

BACKGROUND

Bacterial infection of bile is a common cause of hepatobiliary disease in cats. Whether bile harbors a core microbiota in health or in cases of suspected hepatobiliary disease in cats is unknown.

OBJECTIVES

Establish if gallbladder bile in apparently healthy cats harbors a core microbiota composed of bacterial taxa common to many individuals. Compare results of bile cytology, bile culture, and 16S rRNA gene amplicon sequencing in apparently healthy cats and cats with suspected hepatobiliary disease.

ANIMALS

Forty-three client-owned cats with suspected hepatobiliary disease and 17 control cats.

METHODS

Bile was collected by ultrasound guided cholecystocentesis (cats with suspected hepatobiliary disease) or laparotomy after euthanasia (controls). Bile samples underwent cytologic examination, aerobic and anaerobic culture, and DNA was extracted for 16S rRNA gene amplification and sequencing.

RESULTS

Microbiome sequencing did not identify a core microbiota in control cats or cats having bile sampled because of clinical suspicion for hepatobiliary disease. Microbiome profiles from control cats were indistinguishable from profiles obtained from sampling instruments and reagents that were not exposed to bile (technical controls). Bacterial taxa that could not be explained by contamination or off-target amplification were identified only in samples from cats with bactibilia and positive bile culture results for Escherichia coli. In several E. coli positive samples, microbiome sequencing also identified a small number of potentially co-infecting bacterial genera not identified by culture.

CONCLUSIONS AND CLINICAL IMPORTANCE

Cat bile does not harbor a core microbiota. Uncultured bacteria may contribute to pathogenesis of hepatobiliary disease in cats with bile E. coli infection.

Ultrasonographic measurement of gallbladder wall thickness in fasted dogs without signs of hepatobiliary disease

BACKGROUND

Ultrasound-determined gallbladder wall thickness is widely used to aid in the diagnosis of gallbladder disease, but no reference values supported by published measurement data are available in dogs.

HYPOTHESIS/OBJECTIVE

Establish normal thickness of the gallbladder wall in dogs.

ANIMALS

Fifty-three dogs presented to a referral hospital and required abdominal ultrasound examination for reasons unrelated to primary hepatobiliary disease.

METHODS

Cross-sectional observational study recruiting dogs requiring abdominal ultrasound examination. A standard sequence of gallbladder wall images was recorded for later review. Inclusion criteria were normal ultrasonographic hepatobiliary, pancreatic, and small intestinal findings. Exclusion was determined by 2 European College of Veterinary Internal Medicine (ECVIM)-certified veterinary internists blinded to gallbladder wall thickness data. Dogs were excluded if they had inadequate medical records, a previous history of hepatobiliary, gastrointestinal, or pancreatic disease likely to impact the biliary system (eg, chronic vomiting, nausea, jaundice, diarrhea), unexplained increases in liver enzyme activities, hypoalbuminemia, or ascites. Gallbladder wall thickness was determined by 2 European College of Veterinary Diagnostic Imaging (ECVDI)-certified veterinary radiologists working together to generate a consensus for each dog. The final output was the maximum normal wall thickness for this population of dogs.

RESULTS

The upper limit for gallbladder wall thickness in 53 fasted (8 hours) dogs <40 kg was 1.30 mm (90% confidence interval, 1.19-1.41).

CONCLUSIONS AND CLINICAL IMPORTANCE

Normal gallbladder wall thickness in dogs is lower than previously reported. Additional studies are required to determine potential effects of body weight and the optimal cut-off to distinguish between healthy and diseased gallbladders.

Gallbladder microbiota in healthy dogs and dogs with mucocele formation

To date studies have not investigated the culture-independent microbiome of bile from dogs, a species where aseptic collection of bile under ultrasound guidance is somewhat routine. Despite frequent collection of bile for culture-based diagnosis of bacterial cholecystitis, it is unknown whether bile from healthy dogs harbors uncultivable bacteria or a core microbiota. The answer to this question is critical to understanding the pathogenesis of biliary infection and as a baseline to exploration of other biliary diseases in dogs where uncultivable bacteria could play a pathogenic role. A pressing example of such a disease would be gallbladder mucocele formation in dogs. This prevalent and deadly condition is characterized by excessive secretion of abnormal mucus by the gallbladder epithelium that can eventually lead to rupture of the gallbladder or obstruction of bile flow. The cause of mucocele formation is unknown as is whether uncultivable, and therefore unrecognized, bacteria play any systematic role in pathogenesis. In this study we applied next-generation 16S rRNA gene sequencing to identify the culture-negative bacterial community of gallbladder bile from healthy dogs and gallbladder mucus from dogs with mucocele formation. Integral to our study was the use of 2 separate DNA isolations on each sample using different extraction methods and sequencing of negative control samples enabling recognition and curation of contaminating sequences. Microbiota findings were validated by simultaneous culture-based identification, cytological examination of bile, and fluorescence in-situ hybridization (FISH) performed on gallbladder mucosa. Using culture-dependent, cytological, FISH, and 16S rRNA sequencing approaches, results of our study do not support existence of a core microbiome in the bile of healthy dogs or gallbladder mucus from dogs with mucocele formation. Our findings further document how contaminating sequences can significantly contribute to the results of sequencing analysis when performed on samples with low bacterial biomass.

Diagnostic imaging findings in a referral population of dogs diagnosed with immune-mediated haemolytic anaemia: 50 cases (2015-2018)

OBJECTIVES

To describe and characterise changes documented on thoracic and abdominal imaging of dogs with confirmed immune-mediated haemolytic anaemia.

MATERIALS AND METHODS

Medical records from a referral hospital were searched from 2015 to 2018 for all dogs diagnosed with immune-mediated haemolytic anaemia that underwent thoracic and abdominal imaging by radiography, ultrasound or computed tomography.

RESULTS

Fifty dogs were included. Thoracic imaging revealed abnormalities in 10 dogs (20%) of which lymphadenopathy and cardiomegaly were documented in four dogs (8%) each, and pleural effusion and pleural thickening in one dog (2%) each. Abdominal imaging revealed abnormalities in 43 dogs (86%), in which hepatomegaly and peritoneal effusion were documented in 20 (40%) and 19 dogs (38%), gallbladder wall thickening and sludge in 16 (32%) and 14 dogs (28%) and splenic nodules and splenomegaly in 13 (26%) and seven dogs (14%), respectively. Hepatic and splenic abnormalities were further investigated via fine needle aspirates in 18 dogs and revealed extramedullary haematopoiesis in 12 hepatic (66.7%) and 14 splenic (77.8%) fine needle aspirate samples. Cholecystocentesis was performed in nine dogs with gallbladder abnormalities and revealed bactibilia in three samples (33.3%).

CLINICAL SIGNIFICANCE

In this population of dogs with immune-mediated haemolytic anaemia, thoracic imaging abnormalities were uncommon. Hepatomegaly, peritoneal effusion and gallbladder wall thickening were the most common abdominal imaging findings with bactibilia confirmed in one third of collected bile samples. Hepatosplenomegaly and abdominal lymphadenopathy were not associated with neoplasia in any of the dogs included in this study.

Anicteric Gallbladder Rupture with Elevated Bile Acids in Abdominal Effusion in a Dog with Cholecystitis

Anicteric gallbladder rupture has been rarely described in veterinary medicine, and, generally, it has been related to gallbladder wall necrosis secondary to gallbladder mucocele. A 5 yr old, male, neutered Labrador retriever presented for acute onset anorexia, lethargy, and vomiting. Cholecystitis was diagnosed based on the ultrasonographic findings and bactibilia, and, consequently, medical treatment was established. Despite improvement of the patient, a focal ultrasound of the hepatobiliary tract was performed 72 hr after admission for reassessment, revealing gallbladder wall thickening and abdominal effusion. Intracellular bacteria were present in nondegenerated neutrophils, and the effusion was categorized as septic exudate, compatible with septic peritonitis. Exploratory laparotomy confirmed an anicteric gallbladder rupture potentially secondary to cholecystitis and/or previous cholecystocentesis. The patient was not icteric the day of the surgery, serum bilirubin was within normal limits, abdominal fluid bilirubin concentration was below that of serum, and no bile pigment was detected; however, bile acids were significantly higher in the abdominal effusion compared with the serum concentration. This case describes an anicteric gallbladder rupture in a dog with concomitant cholecystitis and raises the question about the sensitivity of bile acid evaluation as a tool for diagnosis of gallbladder rupture and bile peritonitis in dogs.

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.

Bacterial culture and immunohistochemical detection of bacteria and endotoxin in cats with suppurative cholangitis-cholangiohepatitis syndrome

OBJECTIVE

To characterize the frequency and type of bacterial infection by culture- and immunohistochemical (IHC)-based methods and determine the impact of infection on clinical features and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS).

ANIMALS

168 client-owned cats with S-CCHS (cases).

PROCEDURES

Clinical features, bacterial culture results, culture-inoculate sources, and survival details were recorded. Cases were subcategorized by comorbidity (extrahepatic bile duct obstruction, cholelithiasis, cholecystitis, ductal plate malformation, biopsy-confirmed inflammatory bowel disease, and biopsy-confirmed pancreatitis) or treatment by cholecystectomy or cholecystoenterostomy. Culture results, bacterial isolates, Gram-stain characteristics, and IHC staining were compared among comorbidities. Lipoteichoic acid IHC staining detected gram-positive bacterial cell wall components, and toll-like receptor expression IHC reflected pathologic endotoxin (gram-negative bacteria) exposure.

RESULTS

Clinical features were similar among cases except for more frequent abdominal pain and lethargy in cats with positive culture results and pyrexia, abdominal pain, and hepatomegaly for cats with polymicrobial infections. Bacteria were cultured in 93 of 135 (69%) cats, with common isolates including Enterococcus spp and Escherichia coli. IHC staining was positive in 142 of 151 (94%) cats (lipoteichoic acid, 107/142 [75%]; toll-like receptor 4, 99/142 [70%]). With in-parallel interpretation of culture and IHC-based bacterial detection, 154 of 166 (93%) cats had bacterial infections (gram-positive, 118/154 [77%]; gram-negative, 111/154 [72%]; polymicrobial, 79/154 [51%]). Greater frequency of bacterial isolation occurred with combined tissue, bile, and crushed cholelith inoculates. Infection and gram-positive bacterial isolates were associated with significantly shorter long-term survival times.

CLINICAL RELEVANCE

S-CCHS was associated with bacterial infection, pathologic endotoxin exposure, and frequent polymicrobial infection in cats. Combined tissue inoculates improved culture detection of associated bacteria.

Comprehensive Review of Biliary Peritonitis

Biliary peritonitis is a growing concern in the canine patient and a thorough understanding of the disease will lead to better treatment outcomes. This article reviews the human and veterinary literature pertaining to biliary peritonitis including both scientific reviews and original publications. Compared to human medicine, biliary peritonitis can be difficult to diagnose preoperatively. Multiple risk factors exist increasing the likelihood of development of biliary peritonitis. Treatment recommendations center on stabilization, surgical cholecystectomy, and postoperative supportive care. Clinically, further studies on treatment and prevention in veterinary medicine are warranted.

Bile duct obstruction associated with pancreatitis in 46 dogs

Background

Pancreatitis is a common cause of extrahepatic bile duct obstruction (EHBDO) in dogs. Information describing the clinical course of dogs with pancreatitis associated bile duct obstruction (PABDO) is limited.

Objectives

To describe the clinical course of PABDO in dogs and determine if presumed markers of disease severity are predictors of survival.

Animals

Forty‐six client‐owned dogs with PABDO.

Methods

A retrospective review of medical records from dogs diagnosed with PABDO was performed. Data, including clinical signs and biochemical changes, were collected 6 times throughout the course of disease. Outcome was defined as either survival (discharge from the hospital) or death.

Results

Thirty‐three (79%) out of 42 dogs with PABDO survived. Thirty‐one (94%) of the 33 dogs that survived received medical management alone. Time from onset of clinical signs to initial documented increase in serum bilirubin concentration, peak bilirubin elevation, and initial decline in serum bilirubin concentration were 7 (median), 8, and 15 days, respectively. The median number of days from onset of clinical signs to outcome date was 13. Clinical signs of fever, vomiting, and anorexia were decreased in frequency from the onset of clinical signs to the time of peak bilirubin. Median bile duct dilatation at the time of ultrasonographic diagnosis of PABDO and peak bilirubin were not different between survivors (7.6 mm, 11.7 mg/dL) and nonsurvivors (6 mm, 10.6 mg/dL, P = .12, P = .8).

Conclusions

Dogs with PABDO often have a prolonged course of illness and improve clinically despite biochemical evidence of progression of EHBDO.

Evidence-Based Medicine: Ultrasound-Guided Percutaneous Cholecystocentesis in the Cat

Cholangitis is a common cause of hepatobiliary disease in the cat. Feline cholangitis is characterized as neutrophilic (acute or chronic), lymphocytic, or caused by liver flukes. The neutrophilic form is caused by bacterial infection of the biliary system, and identification of the specific bacterial agent guides treatment. Bile is the sample of choice for cytology and bacterial culture in these cases, and percutaneous ultrasound-guided cholecystocentesis is used to obtain that sample. This review covers the literature that provides evidence for safety and usefulness of percutaneous ultrasound-guided cholecystocentesis as part of the diagnostic work-up of cats suspected of having hepatobiliary disease.

Feline abdominal ultrasonography: what's normal? what's abnormal? The biliary tree

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. The biliary tree encompasses the liver, gall bladder and bile ducts, although only diseases affecting the latter two are discussed here. Diseases of the bile ducts and gall bladder are more common than those of the liver parenchyma and ultrasound plays an important role in their diagnosis.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even differentiating between normal variation and pathological changes can be challenging for all but the most experienced. In addition, a lack of pathological change does not necessarily rule out disease; for example, absence of gall bladder and/or extrahepatic biliary distension is not sufficient to exclude the possibility of biliary obstruction, and in many cases of cholangitis the liver and biliary tree are unremarkable on ultrasound examination.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses the appearance of the normal and diseased biliary system. It is aimed at general practitioners who wish to improve their knowledge and confidence in feline abdominal ultrasound and is accompanied by high-resolution images. Percutaneous ultrasound-guided cholecystocentesis is also covered. Ultrasound examination of the liver was discussed in an article published in January 2019 and an upcoming article will cover hepatic vascular anomalies.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.

Successful treatment of Providencia rettgeri cholecystitis and neutrophilic cholangitis in a cat

Case summary

A 15-year-old male neutered domestic shorthair cat was presented with a recent history of seizures, diarrhoea, lethargy, fever and jaundice. Marked elevation of liver enzyme activity was present and ultrasound examination was suggestive of cholecystitis and hepatitis. Neutrophilic cholangitis was confirmed on histopathology of liver biopsies. Bile culture identified a monomicrobial infection with Providencia rettgeri, which was resistant to multiple antimicrobial agents. The cat was treated with oral pradofloxacin for 4 weeks and remained well 4 months later.

Relevance and novel information

Providencia species are rarely reported in the veterinary literature and are an uncommon cause of disease in humans. The significance of this species in humans relates to the high prevalence of antimicrobial resistance. This is the first report of P rettgeri causing clinical illness in a cat and highlights the importance of bile cultures in hepatic disease.