| Print Date: | June 19, 2013, 9:31 pm |
| Title | Acute focal bacterial nephritis or acute lobar nephronia |
| Text | Acute focal bacterial nephritis (acute lobar nephronia) is an inflammatory mass without drainable pus. The offending organism is usually a gram-negative bacteria that probably ascends through ureteral reflux. The patient generally presents with fever, chills, and flank pain. An intravenous urography during the acute renal infection is often normal but may show diffuse enlargement, delayed calyceal filling, dilatation or distortion of the collecting system.
The ultrasound appearance of this entity is characteristic: a poorly defined mass, internal echoes of lower to equal amplitude as the normal renal cortex, and occasional disruption of the corticomedullary junctions. When the lesion is followed with ultrasound while the patient is on antibiotic therapy, anechoic areas representing liquefaction may be seen. With further follow-up, the mass should resolve. If the mass becomes progressively more well defined and anechoic, however, then the diagnosis of an abscess must be considered, and an aspiration may be performed. An abscess is an anechoic mass with irregular margins and good acoustic enhancement; the number of internal echoes depends on the debris. Since ultrasound cannot definitively differentiate acute lobar nephronia from abscess or even tumor, if there is a clinical question of an abscess, a needle aspiration should be performed. |
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| Contributor | Ultrasound Learning File - © ACR (ACR Learning File®) |
| Peer Reviewer | Perry J. Pickhardt, M.D. (National Capital Consortium) |
| Record Number | : 2041 |
| Created | 2001-05-18 07:47:14-04 |
| Modified | 2006-04-11 14:17:19-04 |
| Category: | Infection, bacteria |
| Location: | Genitourinary |
| Sublocation: | Renal cortex |
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