title: Recurring hyperammonemic encephalopathy induced by bacteria usually not producing urease.
abstract: BACKGROUND
  Hyperammonemic encephalopathy may occur when urease-positive bacteria in the urinary tract produce ammonium which directly enters systemic circulation. Predisposing conditions such as a neurogenic bladder can increase both urinary tract infection and urine stagnation.
  
  
  METHODS
  We describe the case of a 66 years old woman with a neurogenic bladder who twice developed hyperammonemic encephalopathy following urinary tract infection. During the second episode Escherichia coli and Enterococcus faecalis have been isolated in the urine. The neurologic examination showed psychomotor slowing, weak photomotor reflex, nystagmus in the lateral gaze and asterixis. The EEG showed triphasic waves which disappeared along with clinical recovery.
  
  
  CONCLUSIONS
  Escherichia coli and Enterococcus faecalis are commonly considered urease-negative bacteria. Although frequently involved in urinary tract infections, their role in causing hyperammonemic encephalopathy have not been previously reported. Moreover, despite only one case with a neurogenic bladder have been described so far, our is the first patient with reoccurring hyperammonemic encephalopathy secondary to urinary tract infections.
authors.forename: Christian
authors.initials: C
authors.lastname: Cordano
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Traverso
authors.forename: Valentina
authors.initials: V
authors.lastname: Calabrò
authors.forename: Chiara
authors.initials: C
authors.lastname: Borzone
authors.forename: Silvia
authors.initials: S
authors.lastname: Stara
authors.forename: Roberta
authors.initials: R
authors.lastname: Marchese
authors.affiliation: Institute of Neurology, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132 Genova, Italy. lucio.marinelli@unige.it.
authors.forename: Lucio
authors.initials: L
authors.lastname: Marinelli
mesh_terms: D000368:Aged; D001419:Bacteria / Q000201:enzymology*; D001927:Brain Diseases / Q000382:microbiology*; D005260:Female; D006801:Humans; D022124:Hyperammonemia / Q000382:microbiology*; D014510:Urease / Q000096:biosynthesis*
chemical_list: D014510:Urease