Fever, RUQ pain and pus in the liver on CT or US.
Most occur from underlying biliary disease of any kind, other causes include downstream from colon pathology (esp appendicitis), hematogenous, and bad luck.
PPI's increase the risk of liver abscess and mortality (PubMed).
Mono-bacterial infections with Klebsiella pneumoniae (the hyperviscous kind) is not uncommon, especially in diabetics (PubMed). About 10% of Klebsiella liver abscess will have a metastatic complication, most often eyes and lung (PubMed). There may be an association between Klebsiella liver abscesses and malignancy (PubMed).
Amoebic: E. histolytica.
There is a syndrome of aseptic liver abscesses, an autoimmune disease most often associated with IBD and related to Sweets, pyoderma gangrenosum and Behçet disease (PubMed).
I prefer a third generation cephalosporins PLUS metronidazole. Alternatives include a carbapenem OR penicillin/beta-lactamase inhibitors OR a quinolone PLUS metronidazole. Clindamycin can be substituted for the metronidazole.
Drain (if < 2 cm, probably can take care of it medically) PLUS antibiotics if bacterial, antibiotics alone if amoebic, if Candida, probably lipid based amphotericin B.
Relevant links to my Medscape blog
Last Update: 07/15/18.