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.
C. albicans and other fungi can occur in the neutropenic and if aspergillus occurs in a young person for no reason, think of Chronic Granulomatous Disease.
Diabetics are also at risk esp Klebsiella (PubMed).
Mono-bacterial infections with Klebsiella pneumoniae (the hyperviscous kind) is not uncommon, esp 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.
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.
ICD9 Codes (Soon to be supplanted by ICD10)
liver abscess 572.0; amebic 006.3; pyogenic 572.0.