Recurring hyperammonemic encephalopathy induced by bacteria usually not producing urease

Abstract

BackgroundHyperammonemic 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.Case presentationWe 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.ConclusionEscherichia 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.

‘All that glitters is not gold’: when hyperammonaemia is not from hepatic aetiology

“…A similar association has been described by Cordano et al 11 in a 66-year-old woman with a neurogenic bladder who developed hyperammonaemic encephalopathy in two occasions following UTI with E. coli . They hypothesised that causative bacteria developed the ability to produce urease, although this could not be confirmed directly by a laboratory test.…”

“…Frequent pathogens of both urease-producing and non–urease-producing organisms have been implicated in UTI-related hyperammonaemia such as Proteus mirabilis , Klebsiella species,6 8 E. coli ,11 Morganella morganii , corynebacteria7 9 10 and diphtheroid 12. Our patient developed a UTI by E. coli , which is commonly not considered a urease producer.…”

Is there a link between bacteriuria and a reversible encephalopathy in dogs and cats?

“…Case studies in humans have documented acute onset neurological deficits in patients with subclinical or clinical bacteriuria (Samtoy & Debeukelaer 1980, Manepalli et al 1990, Albersen et al 2007, Hufschmidt et al 2010, Eriksson et al 2011, Balogun & Philbrick 2014, Kenzaka et al 2015. Prompt treatment with appropriate antibiotics and supportive care has been associated with rapid improvements in neuro logical status (de Jonghe et al 2002, Sato et al 2008, Cordano et al 2014. To the best of our knowledge, the potential association between bacteriuria and abnormal neurological status has not been investigated in veterinary medicine.…”

“…Human cases are reported with normal plasma ammonia concentrations and/or with infections with non-urease producing bacteria. Thus, other factors are likely to play a role in the development of neurological signs and an area of current research is the role of infection, sepsis and systemic inflammation (Soeno et al 2013, Cordano et al 2014, Kenzaka et al 2015. Cytokine-mediated changes in blood-brain barrier permeability, impaired glutamate uptake by astrocytes and altered expression of γ-aminobutyric acid (GABA) receptors may all contribute to an abnormal neurological status (Shawcross et al 2010, Salgado & Cortes 2013.…”

“…urinary tract infection) bacteria in the lower urinary tract result in clinical signs such as pollakiuria, dysuria and/or haematuria (Weese et al 2019). The mechanisms by which bacteriuria (clinical or subclinical) cause neurological deficits are poorly understood, but are suspected to be multifactorial, and may include hyperammonaemia, urine retention and systemic inflammation (Gabra et al 2003, Albersen et al 2007, Sato et al 2008, Cordano et al 2014, Kenzaka et al 2015. Neurological signs associated with bacteriuria are predominantly consistent with forebrain dysfunction, although in more severe cases presenting with stupor, coma or cranial nerve deficits, brainstem involvement is also thought to occur (Kalvas & Monroe 2019).…”