Clinical Courses of Children With Acute Lobar Nephronia Correlated With Computed Tomographic Patterns

Background: Acute lobar nephronia (ALN) is a complicated acute renal infection that is part of the progression of the inflammatory process of acute pyelonephritis that can progress to renal abscess if left untreated. We examined the place of ALN in the spectrum of upper urinary tract infections. Methods: The medical records of all patients diagnosed with ALN by computed tomography (CT) were reviewed retrospectively in terms of their demographic characteristics, clinical presentations, and laboratory findings. The patterns of the ALN lesions were checked on all contrast-enhanced CT films and the volume of the CT lesions (the extent of renal involvement) was estimated in every patient. Then, the correlation between the clinical presentation and CT lesions was examined. Results: Two distinct CT patterns of ALN lesions were observed in 127 patients: 94 simple ALN and 33 complicated ALN. Simple ALN appeared as striated or wedge-shaped, poorly defined regions of homogeneously decreased nephrographic density, whereas the lesions of complicated ALN showed heterogeneously decreased nephrographic density after contrast enhancement. The volume fraction of the CT lesions correlated well with the duration of fever before (P = 0.006) and after (P < 0.001) treatment in patients with simple ALN, while only the correlation between the fever duration after treatment and the volume fraction of the CT lesions (P < 0.001) was significant in patients with complicated ALN. Patients with complicated ALN were generally older (P = 0.004) and febrile longer after starting antibiotic treatment (P < 0.001). All treatment failures were in the complicated ALN group. Conclusions: Children with ALN comprise 2 groups with different clinical presentations and treatment responses: simple ALN and complicated ALN. We suggest that simple ALN be regarded as a continuation of acute pyelonephritis and require 2 weeks of antibiotic treatment, while complicated ALN is a distinct more severe form requiring a 3-week or longer therapy regimen as the treatment of choice.