Open AccessA new mutation of congenital methemoglobinemia exacerbated after methylene blue treatment
Author(s) -
Yamaji Fuminori,
Soeda Akio,
Shibata Hiroki,
Morikawa Takuya,
Suzuki Kodai,
Yoshida Shozo,
Ogura Shinji
Publication year - 2018
Publication title -
acute medicine and surgery
Language(s) - English
Resource type - Journals
ISSN - 2052-8817
DOI - 10.1002/ams2.335
Subject(s) - methemoglobinemia , methemoglobin , methylene blue , medicine , lidocaine , anesthesia , ascorbic acid , gastroenterology , hemoglobin , food science , chemistry , biochemistry , photocatalysis , catalysis
Case Methylene blue is useful for the treatment of methemoglobinemia. However, even after the patient's methemoglobin (metHb) rate has improved, careful observation is important because they could have undiagnosed congenital methemoglobinemia. In this case, a 67‐year‐old man underwent gastrointestinal endoscopy with the use of lidocaine for local anesthesia. During the examination, he complained of dyspnea and had low SpO 2 despite normal PaO 2 and SaO 2 . He was transferred to our department as a suspected case of acquired methemoglobinemia. Outcome The patient's metHb level was 26.2%. We administered methylene blue i.v. and his metHb level subsequently decreased to 1.6%. However, his metHb level gradually increased to 18.2%, and we suspected that he had congenital methemoglobinemia. We administered riboflavin and ascorbic acid orally, and his metHb level decreased to 6.4%. We also obtained genomic DNA from the patient and identified a novel variant of CYB 5R3 . Conclusion We report a novel variant of congenital methemoglobinemia that deteriorated after methylene blue treatment.