Acute encephalopathy and tubulointerstitial nephritis associated with Yersinia pseudotuberculosis

We report the case of a 28‐month‐old boy with encephalopathy and acute tubulointerstitial nephritis possibly associated with Yersinia pseudotuberculosis (Yp) infection. He was transferred to our center because of impairment of renal function and altered consciousness. He had fever for 5 days after recurrent vomiting and diarrhea. Computed tomography scan was normal, but electroencephalogram (EEG) analyses showed generalized slow wave patterns. Continuous hemodialysis was undergone and then his renal function was improved, but altered consciousness persisted. Single photon emission computed tomography (SPECT) revealed abnormally low signals at entire field, which suggested that he was suffered from encephalopathy. Phenobarbital administration and post‐encephalopathy rehabilitation were started, and he recovered in fully premorbid state with normal EEG and SPECT findings on the 33rd hospital day. Various bacterial cultures were negative, but both Yp antibody and Yp‐derived mitogen (YPM) antibody, the antibody of a specific Yp exotoxin, had an extremely high titer. This is the first report of encephalopathy potentially caused by Yp, indicated by the presence of a high Yp and YPM antibody titer.