A case of acute focal bacterial nephritis with acute kidney injury presenting as acute abdomen

Acute focal bacterial nephritis (AFBN) refers to the bacterial infection of the renal parenchyma without abscess formation. Although AFBN has mainly been reported in pediatric patients, it may be underdiagnosed in adults as it resembles acute pyelonephritis in its clinical presentation. However, the symptoms suggesting acute abdomen is an important clue to diagnose AFBN, which requires additional imaging studies such as contrast-enhanced computed tomography (CECT). Here, we present the case of a 49-year-old female presenting to our emergency room with acute abdomen as well as acute kidney injury (AKI). CECT was performed to rule out critical etiologies of severe abdominal pain and the results revealed multifocal wedge-shaped shadows in the right kidney and diffuse enlargement of bilateral kidneys. We diagnosed the patient with AFBN and treated her through temporal hemodialysis (two sessions) and antibiotics for 23 days. Although AKI associated with AFBN has rarely been reported, her renal dysfunction and other symptoms were completely improved. In conclusion, clinicians should be aware of AFBN and be cautious to avoid the unnecessary invasive interventions.