Surgical Management of Feline Extrahepatic Biliary Tract Diseases

Computed tomographic diagnosis of a common bile duct abscess and secondary extrahepatic biliary duct obstruction in a potbelly pig

A potbelly pig was evaluated for anorexia and icterus. Clinicopathologic abnormalities suggested an active inflammatory hepatobiliary process. Ultrasound and CT of the abdomen revealed an extrahepatic biliary obstruction of the common bile duct (CBD). Surgical exploration and choledochotomy revealed a markedly dilated CBD containing a large volume of intraluminal inspissated biliary material. This case report describes the imaging findings of an extrahepatic biliary obstruction secondary to abscessation within the CBD in a pig.

Diagnostic and predictive ability of hyperbilirubinemia severity in cats: A multicenter retrospective study

BACKGROUND

Total serum bilirubin concentration (TBIL) can provide useful information on several pathophysiological conditions in cats. Nevertheless, whether the variable severity classification of hyperbilirubinemia can reliably indicate certain disease processes or predict a biliary obstruction (BO) has not been investigated.

HYPOTHESIS/OBJECTIVE

Determine if hyperbilirubinemia of variable severity can assist clinicians to identify BO, which often is considered a surgical emergency.

ANIMALS

Two-hundred sixteen client-owned cats.

METHODS

Data were retrospectively collected from all cats (January 2015-August 2022) with an increased TBIL (>0.58 mg/dL [>10 μmol/L]) presented to 3 referral centers in the United Kingdom (UK). Presenting clinical features and diagnostic outcomes were collected. The predictive ability of TBIL to indicate BO was evaluated by multivariable binary logistic regression modeling and receiver operating characteristic (ROC) curves.

RESULTS

Median TBIL was 1.73 mg/dL (range, 0.59-26.15; 29.5 μmol/L; range, 10.1-447.1) with severity classification of hyperbilirubinemia categorized as mild (>0.58-2.92 mg/dL; >10-50 μmol/L; 68.1%), moderate (>2.92-5.85 mg/dL; >50-100 μmol/L; 17.6%), severe (>5.85-11.70 mg/dL; >100-200 μmol/L; 9.7%) and very severe (>11.70 mg/dL; >200 μmol/L; 4.6%). Biliary obstruction was present in 17 (7.9%) cats, all of which received recommendation for emergency surgery. Median TBIL in cats with BO (9.69 mg/dL; 165.7 μmol/L) differed significantly from those without obstruction (1.51 mg/dL; 25.8 μmol/L; P < .01). The optimal TBIL cut-off to discriminate between cats with and without BO was ≥3.86 mg/dL (≥66 μmol/L) with a sensitivity of 94.1% and specificity of 82.4%. Using multivariable logistic regression, as age increased, the odds of BO increased significantly (odds ratio, 1.20; 95% confidence interval, 1.01-1.42; P = .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

As part of a thorough clinical assessment, the severity classification of hyperbilirubinemia has the potential to predict the likelihood of a BO and to discriminate between cats that may or may not require surgery for BO at a suggested cut-off of ≥3.86 mg/dL (≥66 μmol/L). Alongside TBIL, age is also useful when assessing for the likelihood of BO in a cat presented with hyperbilirubinemia.

Prevalence and clinical relevance of cholelithiasis in cats: A multicenter retrospective study of 98 cases

BACKGROUND

Cholelithiasis is an uncommon and mainly incidental finding in dogs; current literature on this topic is scarce in cats.

HYPOTHESIS

Report prevalence, clinical presentation, management, and outcome of cholelithiasis in cats.

ANIMALS

Ninety-eight cats with cholelithiasis.

METHODS

Retrospective multicenter case series. Electronic databases from 3 hospitals were searched for cats diagnosed with cholelithiasis by ultrasonography (US). Cholelithiasis was classified as incidental (IC) or symptomatic (SC) depending on clinicopathological signs, biliary tract US appearance, and presence of another disease potentially explaining the clinical presentation. Multivariate analysis was used to investigate factors associated with clinical expression of cholelithiasis and, within the SC group, survival.

RESULTS

The observed prevalence of cholelithiasis was 0.99% (95% confidence interval [CI], 0.79%-1.19%) among cats that underwent abdominal US. Cholelithiasis was classified as IC in 41% and SC in 59%. Choleliths found in multiple locations within the biliary tract (odds ratio [OR], 8.11; 95% CI, 2.32-34.15; P = .001) or associated with US signs of obstruction (OR, 18.47; 95% CI, 2.13-2413.34; P = .004) were significantly associated with SC. Concurrent hepatobiliary diseases were suspected or confirmed in 83% of cases with SC. Forty-three cats (74%) with SC survived to discharge. Biliary tract obstruction (BTO) was negatively associated with survival (OR, 13.87; 95% CI, 1.54-124.76; P = .001). None of the cats with IC that had available follow-up (47%) developed clinicopathological signs related to cholelithiasis.

CONCLUSIONS AND CLINICAL IMPORTANCE

Cholelithiasis is uncommon and can be asymptomatic in cats. Symptomatic cholelithiasis frequently is associated with another hepatobiliary disease or BTO or both. Biliary tract obstruction is associated with poorer outcome.

Surgical Management Of Feline Biliary Tract Disease: Decision-making and techniques

PRACTICAL RELEVANCE

Diseases of the hepatobiliary system are not uncommon in first-opinion practice. The anatomy of the feline hepatobiliary tract differs from that of dogs and may predispose cats to inflammatory hepatobiliary disease. Case management can be challenging, and the prognosis is variable and dependent on the underlying disease process.

CLINICAL CHALLENGES

Biliary tract disease in the cat has non-specific clinical signs that overlap with those of diseases of other body systems. Diagnostic tests of the hepatobiliary system are widely available, but interpretation of results can be challenging. Deciding on medical or surgical management can also be challenging; for example, various degrees of cholestasis may be seen with different diseases and disease severities, and will influence the decision to manage the patient medically or surgically. Surgery is indicated in cases of bile peritonitis, severe cholestasis, focal neoplasia or disease that is refractory to medical management. Intensive perioperative and postoperative management, with 24 h hospitalisation facilities, is essential.

AUDIENCE

This review article is written for the small animal general/primary care practitioner, with an emphasis on decision-making in the surgical management of feline hepatobiliary disease.

EVIDENCE BASE

Evidence available in the published literature is reviewed and presented, and the inherent limitations are discussed.

Surgical Anatomy of the Gastrointestinal Tract in Cats

In cats, the gastrointestinal tract is one of the regions in which surgical procedures are most frequently performed by veterinary surgeons; therefore, knowledge of the surgical anatomy of the feline gastrointestinal tract is of high importance. The main surgical procedures performed include gastrotomy, gastrectomy, enterotomy, and enterectomy, as well as procedures in the liver and pancreas. There are also anatomical differences between dogs and cats, increasing the need for deep knowledge of the anatomy treated in the different surgical approaches. The aim of the present review is to describe in detail the anatomy of the gastrointestinal tract in cats highlighting the anatomical regions of significant importance in different surgical procedures.

Cholangiopancreatography in cats: a post-mortem comparison of MRI with fluoroscopy, corrosion casting and histopathology

In human medicine, magnetic resonance cholangiopancreatography (MRCP) is a valuable diagnostic tool for hepatobiliary and pancreatic diseases. In veterinary medicine, however, data evaluating the diagnostic value of MRCP are limited. The primary objectives of this prospective, observational, analytical investigation were to assess whether MRCP reliably visualizes the biliary tract and pancreatic ducts in cats without and with related disorders, and whether MRCP images and measurements of the ducts agree with those of fluoroscopic retrograde cholangiopancreatography (FRCP), corrosion casting and histopathology. A secondary objective was to provide MRCP reference diameters for bile ducts, GB, and pancreatic ducts. Donated bodies of 12 euthanized adult cats underwent MRCP, FRCP, and autopsy with corrosion casting of the biliary tract and pancreatic ducts using vinyl polysiloxane. Diameters of the biliary ducts, gallbladder (GB), and pancreatic ducts were measured using MRCP, FRCP, corrosion casts and histopathologic slides. There was an agreement between MRCP and FRCP in measuring diameters of the GB body, GB neck, cystic duct, and common bile duct (CBD) at papilla. Strong positive correlations existed between MRCP and corrosion casting for measuring GB body and neck, cystic duct, and CBD at the extrahepatic ducts' junction. In contrast to the reference methods, post-mortem MRCP did not visualize right and left extrahepatic ducts, and pancreatic ducts in most cats. Based on this study, MRCP with 1.5 Tesla can be regarded as a contributory method to improve the assessment of feline biliary tract and pancreatic ducts when their diameter is >1 mm.