RT Journal Article SR Electronic T1 Lesson of the month 2: A case of nitrous oxide-induced pancytopenia JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP 129 OP 130 DO 10.7861/clinmedicine.19-2-129 VO 19 IS 2 A1 Felicity Norris A1 Patrick Mallia YR 2019 UL http://www.rcpjournals.org/content/19/2/129.abstract AB An 18-year-old female patient presented to the emergency department with non-specific neurological and gastrointestinal symptoms and was found to be pancytopenic. Her vitamin B12 level was low with a normal mean corpuscular volume and her full blood count 2 months previously had been within normal range. She reported heavy use of nitrous oxide over the previous 2 weeks and other investigations revealed no cause for her pancytopenia. Her pancytopenia resolved with discontinuation of nitrous oxide and vitamin B12 treatment. Heavy use of nitrous oxide should be considered as a cause of pancytopenia.