Renal subcapsular abscess is a very rare disease that is defined by a suppurative process localized to a space between the renal capsule and the renal parenchyma. The course and management of subcapsular abscesses have received less attention than those of renal and perirenal abscesses. We describe a 63-year-old diabetic woman who presented with intermittent fever of 1 month's duration. She was initially treated for suspected acute pyelonephritis then referred to our hospital because of poor clinical response to cefazolin plus gentamicin. Computed tomography of the abdomen revealed a huge subcapsular abscess with displacement and compression of the left renal parenchyma. A percutaneous catheter was inserted and left in place for 8 days; a total of approximately 850 mL of pus was drained. Culture of the pus yielded Klebsiella pneumoniae and Enterobacter cloacae. A 2-week course of moxalactam was administered on the basis of the results of in vitro antibiotic susceptibility testing. The distorted renal parenchyma appeared normal at sonographic follow-up examination 3 weeks after hospitalization. The course and management of this rare entity are presented as a reminder to physicians that renal subcapsular abscess could manifest as fever of unknown origin in a diabetic patient. A high degree of clinical suspicion is required for early diagnosis and treatment in order to achieve a satisfactory outcome.
