Pyogenic hepatic abscess. A 10-year population-based retrospective study.

A 10-year retrospective survey was undertaken of patients with pyogenic hepatic abscesses (PHA). Fifty-two patients fulfilled the criteria of PHA, equivalent to a mean annual incidence of 11/1,000,000. The main symptom was fever. Laboratory tests were compatible with infection, slightly elevated alkaline phosphatase being the only test pointing towards the liver as the focus of infection. Forty-one patients (79%, 95% CL, 68-90%) had positive cultures from aspirated pus, with a total of 79 isolates. Enteric Gram-negative rods accounted for 45% and anaerobic bacteria for 31% of PHA isolates. Gram-positive cocci, predominantly non-haemolytic streptococci, were the third largest group (19%), but were rare among blood isolates. Positive blood cultures were found in 21 patients (40%, 95% CL, 27-54%), with a total of 28 isolates. Percutaneous drainage was performed in 26, percutaneous needle aspiration in 10, combinations thereof in 5, and abdominal surgery in 5. Forty-nine patients received systemic antibiotic therapy, four of whom were treated with antibiotics only. Seven recurrences occurred and the overall case fatality rate was 6% (95%, CL 0-12%), which might reflect a low rate of underlying malignant diseases in our study material.