Today we discussed a case of pyogenic liver abscess. This is a very hot topic right now! Incidence increases with age, which may explain why we are seeing so many of these on general internal medicine wards. They most commonly involve the right lobe of the liver, as it is larger and receives more blood supply.
Causes of pyogenic liver abscess can be categorized as follows:
1. Biliary tract disease: ascending cholangitis caused by obstruction (stone, pancreatic or cholangioCA, stricture)
2. Portal vein seeding as a result of intraabdominal disease: this can be secondary to appendicitis, diverticulitis, bowel perforation, malignancy. May be accompanied by pyelephlebitis (suppurative thrombophlebitis of the portal vein).
3. Hepatic artery seeding: from systemic bacteremia with or without bacterial endocarditis
4. Contiguous focus of infection: gallbladder disease, subphrenic or perinephric abscess.
5. Traumatic: liver laceration, post-resection, post radiofrequency ablation, migrated foreign body (eg: fishbones through gastric antrum).
5. "Primary"=cryptogenic: Hypermucoviscous variants of Klebsiella pneumoniae are increasingly being recognized as a cause. This is seen most commonly in patients of Southeast Asian descent and has been associated with diabetes mellitus.
Microbiology of liver abscesses: Many are polymicrobial (especially if secondary to biliary tract disease or intraabdominal infections). Common pathogens are: E.Coli, Klebsiella pneumoniae, Strep (including Strep anginosus group- famous for abscesses), anaerobes.
Treatment is focused on source control=drainage of abscess. Broad-spectrum antibiotics (eg:ceftriaxone,flagyl) are used until a specific pathogen is isolated from drainage or blood cultures (positive 50% of the time). Antibiotics are initially intravenous, then stepped down to oral for a total 4-6 week course.
Check out this recent case from TGH with a review on the topic by our very own Wayne Gold and Derek MacFadden: Here
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