Pyogenic liver abscess

First described by Hippocrates around 400 BC, pyogenic liver abscess is an uncommon hepatic infection, but is associated with significant morbidity and healthcare costs. With the advent of imaging techniques that allow for prompt diagnosis, potent antibiotics, and effective drainage procedures, the mortality from pyogenic liver abscess has declined dramatically over the past several decades. Epidemiology The epidemiology of liver abscesses has changed significantly over the years. There is increasing recognition that geography plays a significant role in the demographics, etiologic factors, and clinical presentation of pyogenic liver abscesses. In the first large published series of cases of pyogenic liver abscess in the United States in 1938, there was an incidence of 8 cases per 100 000 admissions and a mortality rate of 72%. More recent US-based population studies estimate the annual incidence to be 3.6 per 100 000 population, with a higher incidence among men than women (incidence risk ratio 1.85). Significantly higher incidence rates have been reported in Taiwan at 17.6 per 100 000 population. Reported risk factors include diabetes, underlying hepatobiliary disease, and liver transplantation. In-hospital mortality ranges from 2% to 12% in developed countries and has been reported at 5.6% in the United States. Risk factors for mortality include older age; comorbidities such as cirrhosis, chronic renal failure, and malignancy; the presence of anaerobic infection; and open surgical drainage. The significant decline in associated mortality reflects changes in the underlying source of bacterial seeding and advances in diagnostic and treatment options.