Open AccessMetabolic encephalopathy caused by nitrous oxide (‘laughing gas’) induced hyperammonaemia
Author(s) -
Marissa Ginette Danielle Vive,
Galia V. Anguelova,
Sjoerd N. Duim,
H.M.A. Hofstee
Publication year - 2019
Publication title -
bmj case reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.231
H-Index - 26
ISSN - 1757-790X
DOI - 10.1136/bcr-2019-232163
Subject(s) - lactulose , medicine , nitrous oxide , methylmalonic acid , encephalopathy , hyperammonemia , vitamin b12 , vomiting , gastroenterology , anesthesia , pediatrics
A 26-year-old man presented at the emergency department with confusion and decreased consciousness after several days of vomiting. In the preceding 6 months, he had used a 2-litre tank of nitrous oxide (N 2 O) weekly. His metabolic encephalopathy was caused by hyperammonaemia which probably resulted from interference of N 2 O-induced vitamin B 12 deficiency with ammonia degradation. A catabolic state might have contributed to the hyperammonaemia in this case. After treatment with vitamin B 12 and lactulose, both his consciousness and hyperammonaemia improved. He reported no residual complaints after 3 months of follow-up. Since N 2 O is increasingly used as a recreational drug, we recommend considering hyperammonaemia as a cause of metabolic encephalopathy in cases of N 2 O use and altered mental status.