A Case of Acute Encephalopathy Associated with Acute Focal Bacterial Nephritis

Acute encephalopathy is a syndrome characterized by an acute onset of disturbance of consciousness. Many acute encephalopathies are caused by viral infections; however, they can also be a result of bacterial infections. Acute focal bacterial nephritis (AFBN) can cause neurological symptoms, such as irritation, unconsciousness, and seizures. In some cases, AFBN-associated acute encephalopathy has also been reported. This report describes the first case of acute encephalopathy with AFBN without significant findings on brain MRI. The patient was a 3-year-old male, who had two episodes of febrile seizures at the ages of 1 and 2 years. He developed disturbance of consciousness, irritability, excitability, and neck stiffness on the day after admission. There were no abnormal findings on brain MRI; however, a generalized high-voltage slow wave was noted on electroencephalography (EEG). His urinary sediment count was elevated, and Morganella morganii and Enterococcus faecalis were detected in the urinary culture. A diagnosis of acute encephalopathy with urinary tract infection (UTI) was made. Intravenous (IV) antibiotics were administered to treat the UTI, while methylprednisolone pulse therapy and IV immunoglobulin were administered to treat acute encephalopathy. Additionally, AFBN was detected in both kidneys on contrast-enhanced CT. The patient received a second course of methylprednisolone pulse therapy due to the persistent high voltage slow wave noted on the EEG on day 8. Furthermore, contrast-enhanced CT revealed AFBN in both kidneys. The final diagnosis was acute encephalopathy with AFBN; however, we had initially diagnosed febrile seizures associated with UTI. It should be noted that acute encephalopathy is associated with AFBN.