A splenic abscess is a walled-off infection within the spleen. Splenic abscesses are rare, although their identification has increased with more readily available cross-sectional imaging. Trauma, immunosuppression, and infection are the primary risk factors for developing a splenic abscess. Infection can occur spontaneously, often in the setting of immunosuppression, seeding from endocarditis, or as a result of ischemic injury with secondary abscess formation.

Patients most typically present with fevers, emesis, and left upper quadrant abdominal pain. They may have splenomegaly. Causal organism varies by risk factor:

• Streptococcus and Staphylococcus: seen in patients with endocarditis
• Escherichia coli and Klebsiella pneumoniae: seen in patients with intraabdominal infections
• Mycobacterium tuberculosis, Mycobacterium avium complex, Salmonella typhi, and Pneumocystis jiroveci: seen in patients with human immunodeficiency virus (HIV) disease and AIDS
• Mycobacterium spp., fungi (Candida albicans), protozoa: seen in immunocompromised patients

Splenic abscesses can form fistulae within the gastrointestinal tract, pleural space, or lung parenchyma or they may perforate, leading to peritonitis.