Is Acute Lobar Nephronia the Midpoint in the Spectrum of Upper Urinary Tract Infections between Acute Pyelonephritis and Renal Abscess?

Objective: To examine acute lobar nephronia (ALN) in the spectrum of upper urinary tract infections between acute pyelonephritis (APN) and renal abscess. Study design: Medical records of 115 patients diagnosed with APN, ALN, or renal abscess with computed tomography (CT) were reviewed retrospectively. CT lesions and patterns of ALN were checked, and the volume of CT lesions was estimated in every patient. Then the correlation between clinical presentation and CT lesions was examined. Results: The study included 21 patients with APN, 85 with ALN (63 simple ALN, 22 complicated ALN), and 9 with renal abscesses. The volume fraction of CT lesions correlated well with duration of fever before and after treatment in patients with APN or simple ALN, and only the correlation between fever duration after treatment and CT lesions was significant in patients with complicated ALN or renal abscess. Conclusions: We suggest that simple ALN be regarded clinically as the progression of APN. By contrast, complicated ALN is a distinct, more severe disease entity, and it may relate to or progress to renal abscess. ALN is probably not the midpoint in the traditional dynamic spectrum of upper urinary tract infections between APN and renal abscess.