Bacterial liver abscess and other bacterial infections

Abstract

Bacteria may cause liver disease by directly invading the liver parenchyma or the bile ducts, or indirectly by eliciting a hepatic response to extrahepatic, predominantly pulmonary and urogenital infections. Systemic effects of toxins and other mediators are held responsible for hepatic inflammatory and cholestatic reactions (see Chapters 19 and 52). Bacterial liver diseases encompass a broad clinical spectrum that includes asymptomatic patients, cases with slightly elevated liver enzymes, patients with fulminant hepatitis and acute liver failure, and chronic liver disease with formation of abscesses. There is no characteristic constellation of liver enzymes in bacterial infections. Mostly AST is elevated accompanied by varying elevation of alkaline phosphatase levels. Jaundice is often present in septic patients, in pneumococcal pneumonia, toxic shock syndrome, leptospirosis and in relapsing fever, but its absence does not allow to exclude these conditions. A high index of suspicion, derived from the clinical context, must be kept to diagnose involvement of the liver in bacterial diseases. The diagnosis is confirmed by serologic, microbiologic, noninvasive (ultrasound, CT, MRI) and invasive (liver biopsy) imaging techniques.