Lobar nephronia, also known as acute focal nephritis, refers to an intermediate stage between acute pyelonephritis and renal abscess, and is a focal region of interstitial nephritis.
It appears as a wedge of poorly perfused renal parenchyma, without a cortical rim sign.
The condition is discussed further as part of the article on acute pyelonephritis.
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Epidemiology
Acute lobar nephronia is commonly found in children. However, immunosuppressed adults, those with abnormalities in the genitourinary tract, or have other underlying conditions such as diabetes mellitus and liver cirrhosis may also be affected by this condition 2.
Clinical presentation
Clinical features for lobar nephronia are similar to acute pyelonephritis and renal abscess 2:
fever
flank pain
leucocytosis
pyuria
elevated C-reactive protein
Radiographic features
Ultrasound
focal hyperechogenicity3
diffuse nephromegaly3
CT
CT with IV contrast is the gold standard for diagnosing lobar nephronia. It shows a wedge shaped non-enhancing lesion with ill-defined borders 2.
History and etymology
Lobar nephronia was first described by Rosenfield et al. in 1978 2.
Differential diagnosis
renal infarction: in these patients the cortical rim sign is present, and clinical presentation is different, without inflammatory/infectious symptoms