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Ammonia: what adult neurologists need to know
  1. Rick Meijer1,2,
  2. Umesh Vivekananda3,
  3. Simona Balestrini3,4,
  4. Matthew Walker3,
  5. Robin Lachmann2,
  6. Johannes Haeberle5,
  7. Elaine Murphy2
  1. 1 Department of Internal Medicine, Amsterdam University Medical Centers, Location VU University Medical Center, Amsterdam, The Netherlands
  2. 2 Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London, UK
  3. 3 Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
  4. 4 Chalfont Centre for Epilepsy, Buckinghamshire, UK
  5. 5 Department of Pediatrics, University Children’s Hospital Zurich and Children’s Research Centre, Zurich, Switzerland
  1. Correspondence to Elaine Murphy, Consultant Adult Inherited Metabolic Disease, Charles Dent Metabolic Unit, Internal Mailbox 92, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; elaine.murphy8{at}


Hyperammonaemia is often encountered in acute neurology and can be the cause of acute or chronic neurological symptoms. Patients with hyperammonaemia may present with seizures or encephalopathy, or may be entirely asymptomatic. The underlying causes are diverse but often straightforward to diagnose, although sometimes require specialist investigations. Haemodialysis or haemo(dia)filtration is the first-line treatment for acute severe hyperammonaemia (of any cause) in an adult. Here we discuss our approach to adult patients with hyperammonaemia identified by a neurologist.

  • Coma
  • epilepsy
  • metabolic disease

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  • RM and UV contributed equally.

  • Contributors EM, SB, MW, RL and JH agreed the concept of the article. RM and UV wrote the first draft of the article. EM completed the major revisions of the article. SB, MW, RL and JH reviewed and revised the article.

  • Funding This work was undertaken at UCLH/UCL, which received a proportion of funding from the Department of Health’s NIHR Biomedical Research Centres’ funding scheme. SB is supported by Muir Maxwell Trust and by the Epilepsy Society.

  • Competing interests The authors declare that they have no competing interests.

  • Patient consent for publication Not required.

  • Ethics approval Not required.

  • Provenance and peer review Commissioned. Externally peer reviewed by Michel Chan, Sydney, Australia.

  • Data availability statement Data are available on request.

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