Clinical and pathologic characteristics of nontyphoidal salmonella encephalopathy

Objective: To investigate the clinical and pathologic characteristics of primary encephalopathy caused by nontyphoidal salmonellosis (NTS). Methods: Case records of six Japanese hospitals from 1994 to 1999 were reviewed. Eight cases of primary NTS encephalopathy were identified based on strictly defined criteria: 1) encephalopathic feature defined as altered state of consciousness, altered cognition or personality, or seizures; 2) detection of nontyphoidal Salmonella species in stool; 3) absence of other viral or bacterial infection associated with CNS abnormalities; and 4) absence of alternative explanation by underlying neurologic or systemic disease. Three patients died, three had severe sequelae, and two recovered completely. The authors analyzed their clinical course, neurologic symptoms, and histopathologic findings. Results: NTS encephalopathy was clinically characterized by diffuse and rapidly progressive brain dysfunction and circulatory failure that developed following enteritis. There was no evidence of severe dehydration or sepsis, and encephalopathy was rarely accompanied by abnormal laboratory data, except elevated CSF opening pressure, brain edema on CT, and slow waves on EEG. Pathologic findings included minimal ischemic damage and mild edema in the brain, microvesicular fatty change of the liver, severe enterocolitis but no evidence of dehydration, and no fatal organ damage including microvasculature and endothelial cells. Conclusion: Noninfectious encephalopathy associated with nontyphoidal salmonella infection is a distinctive clinical entity that can be differentiated from Reye's syndrome and Ekiri.