title: Whippits, nitrous oxide and the dangers of legal highs.
abstract: Nitrous oxide is increasingly being used as a recreational drug. Prolonged use of nitrous oxide can have disabling neurological sequelae due to functional inactivation of vitamin B₁₂. We present three cases illustrating the neurological complications of using nitrous oxide. Two of these patients received nitrous oxide as a consequence of repeated hospital attendance and the third via 'Whippit' canisters used in cream dispensers, which are now widely available. Two patients developed sensorimotor peripheral neuropathy with demyelinating features with no clinical or imaging evidence of myelopathy, emphasising that not all patients develop subacute combined degeneration of the spinal cord (the typical presentation of functional vitamin B12 deficiency). The diagnosis was based upon the history of nitrous oxide use and raised levels of homocysteine and/or methylmalonic acid. All patients were treated with parenteral vitamin B12 with partial recovery, though two were left significantly disabled.
authors.affiliation: Department of Neurology, John Radcliffe Hospital, Oxford, UK.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Thompson
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK.
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Leite
authors.affiliation: MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lunn
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK.
authors.forename: David L H
authors.initials: DL
authors.lastname: Bennett
mesh_terms: D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D009422:Nervous System Diseases / Q000188:drug therapy*; D009609:Nitrous Oxide / Q000009:adverse effects*; D013118:Spinal Cord Diseases / Q000139:chemically induced*; D014806:Vitamin B 12 Deficiency / Q000139:chemically induced*; D055815:Young Adult
chemical_list: D018712:Analgesics, Non-Narcotic; D009609:Nitrous Oxide
keywords: NEUROPATHY; TOXICOLOGY