In the past, mortality rates were about 50% without treatment. In more recent reports, there was a significant improvement in mortality rate to less than 15%. This is due to more accurate diagnosis and treatment using percutaneous drainage, more effective antibiotics, and better supportive care.
Perinephric abscesses can be the consequence of pyonephrosis due to an obstruction nephrolith, recurrent pyelonephritis, or the rupture of a corticomedullary intra-nephric abscess. Perinephric abscess can also result from the spread of infection from extraperitoneal sites via hematogenous dissemination or from infection from adjacent structures such as the bowel, pancreas, and spine.
Escherichia coli is the most common etiologic organism in perinephric abscess. Proteus mirabilis commonly causes infective calculi. Other bacteria that can cause this infection include Staphylococcus aureus, Klebsiella, Enterobacter, Pseudomonas, Serratia, and Citrobacter species. Some infections may be polymicrobial. Enteric gram-negative organisms are common pathogens in the case of local extension, and gram-positive cocci in the case of hematogenous spread.
The clinical presentation is usually characterized by the insidious onset of fever, flank or abdominal pain, fatigue, and weight loss. Physical findings include flank or costovertebral tenderness. A palpable mass may be present in some cases.
Related topic: Renal Abscess
N15.1 – Renal and perinephric abscess
80640009 – Perinephric abscess
Differential Diagnosis & Pitfalls
- Acute complicated pyelonephritis
- Renal abscess
- Renal cell carcinoma
- Papillary necrosis
- Emphysematous pyelonephritis
- Xanthogranulomatous pyelonephritis
- Psoas abscess
- Infected renal cyst
- Pyomyositis of the abdominal wall or paraspinal muscles
- Subphrenic abscess
- Osteomyelitis of the spine with spread to the paraspinal tissues