# Multidisciplinary Surgical Treatment of Hepatic Abscess in a Geriatric Dog with Congenital Extrahepatic Portosystemic Shunt

## TL;DR

A geriatric dog with a liver shunt developed a resistant liver abscess, requiring surgery to remove part of the liver and correct the shunt.

## Contribution

This is the first report linking congenital portosystemic shunts to hepatic abscesses in dogs.

## Key findings

- A geriatric dog with EHPSS developed a multidrug-resistant hepatic abscess.
- Surgical intervention including lobectomy, cholecystectomy, and shunt attenuation resolved the infection.
- Postoperative recovery showed normalized liver enzymes and increased liver size.

## Abstract

Hepatic abscesses are rare in dogs and are most commonly associated with biliary disease or ascending bacterial infection. Congenital extrahepatic portosystemic shunts (EHPSS) are known to impair hepatic perfusion and immune clearance; however, their potential role in predisposing dogs to hepatic abscess formation has not been previously reported. This case describes a geriatric dog with congenital EHPSS that developed a multidrug-resistant hepatic abscess unresponsive to targeted antimicrobial therapy. Definitive treatment required a multidisciplinary surgical approach, including partial hepatic lobectomy, cholecystectomy, and shunt attenuation. The clinical course and histopathologic findings suggest that long-standing portosystemic shunting may impair hepatic immune function and contribute to intrahepatic bacterial persistence. This report highlights EHPSS as a potential, previously underrecognized risk factor for hepatic abscess formation and emphasizes the importance of addressing both the infectious focus and the underlying vascular abnormality to achieve successful long-term outcomes in affected dogs.

Hepatic abscesses are uncommon in dogs and typically develop secondary to biliary tract disease or ascending bacterial infections. Although congenital extrahepatic portosystemic shunt (EHPSS) is known to impair hepatic perfusion and immune clearance, its potential role in predisposing geriatric dogs to hepatic abscess formation has not been previously reported. This case report describes the diagnostic approach, therapeutic decision-making, and clinical outcome of a geriatric dog in which a multidrug-resistant hepatic abscess occurred in association with congenital EHPSS, and to propose a pathophysiologic link between chronic portal hypoperfusion and intrahepatic infection. An 11-year-old neutered male Maltese dog with a known EHPSS presented with acute anorexia and lethargy. Diagnostic imaging revealed a hepatic abscess adjacent to the gallbladder, and cytology confirmed a septic process. Despite targeted meropenem therapy based on antimicrobial susceptibility testing, the abscess failed to regress and C-reactive protein levels continued to rise. Concern for persistent biliary contamination and impaired hepatic immune clearance led to surgical intervention. A combined procedure—partial hepatic lobectomy, cholecystectomy, and shunt attenuation—was performed. Postoperative hypotension was managed successfully with vasopressors and transfusion. The patient recovered uneventfully, and at four-month follow-up, hepatic enzyme activities normalized and liver size increased. These findings highlight the need to evaluate hepatic infections in dogs with EHPSS as a potential consequence of impaired hepatic immune clearance rather than an incidental finding.