Acute Focal Bacterial Nephritis Associated With Reversible Splenial Corpus Callosum Lesion

Acute focal bacterial nephritis (AFBN) is a localized bacterial infection of the kidney, which presents as an inflammatory mass without formation of a frank abscess. Rare cases of AFBN are accompanied by neurological symptoms such as meningeal irritation, unconsciousness, and seizures. Clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is characterized by transient high signal intensity splenial lesions on diffusion-weighted magnetic resonance imaging. MERS can be divided into two types: type 1 with an isolated splenium of the corpus callosum and type 2 with extensive white matter and/or entire callosal lesions. We experienced three rare cases of pediatric AFBN associated with neurological symptoms, including unconsciousness and reversible splenial corpus callosum lesion. The first case was an 8-year-old girl who had neurological symptoms, including unconsciousness, and AFBN was associated with MERS type 2. The second (5-year-old boy) and third (5-year-old girl) cases had neurological symptoms, including unconsciousness and AFBN with MERS type 1. Two of the three cases had AFBN caused by Escherichia coli . All three cases showed high levels of urinary β2-microglobulin (B2MG). AFBN should be suspected in children with fever, rapid clinical deterioration, neurological symptoms including unconsciousness, and high urinary B2MG level. We recommend that abdominal enhanced computed tomography should be performed for the diagnosis of AFBN. Int J Clin Pediatr. 2020;9(3):82-86 doi: https://doi.org/10.14740/ijcp395