Lobar nephronia

Last revised by Ahmad Alomari on 1 Feb 2024

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.

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 features for nephronia are similar to acute pyelonephritis and renal abscess 2:

  • fever

  • flank pain

  • leukocytosis

  • pyuria

  • elevated C-reactive protein

  • bulky kidney

  • loss of cortico-medullary differentiation 2

Contrasted CT scan is the gold standard for diagnosing nephronia. It shows a wedge shaped non-enhancing lesion with ill-defined borders 2

Nephronia was first described by Rosenfield et al in 1978 2.

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