title: An unusual cause of cyanosis in a patient with COPD.
abstract: We present a case of acquired methaemoglobinaemia related to the prolonged use of dapsone in a patient with chronic hypoxia. The patient was initially successfully treated for infective exacerbation of chronic obstructive pulmonary disease (COPD). However, he remained persistently hypoxic on pulse oximetry despite a normal PaO2 on arterial blood gas sampling. His fraction of methaemoglobin (FMetHb) was found to be elevated at 13%. After cessation of dapsone, his clinical cyanosis recuperated, his exercise tolerance and functional capacity improved and his FMetHb normalised to 1%.
authors: Department of Respiratory Medicine, St George's Hospital, London, UK. yjchang@doctors.org.uk
authors: You-Jin
authors: YJ
authors: Chang
authors: Haider
authors: H
authors: Ali
authors: Adrian
authors: A
authors: Draper
authors: Felix
authors: F
authors: Chua
mesh_terms: D000890:Anti-Infective Agents / Q000009:adverse effects*; D003490:Cyanosis / Q000139:chemically induced*; D003622:Dapsone / Q000009:adverse effects*; D003874:Dermatitis Herpetiformis / Q000188:drug therapy*; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008708:Methemoglobinemia / Q000139:chemically induced*; D008875:Middle Aged; D010092:Oximetry; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000628:therapy*
chemical_list: D000890:Anti-Infective Agents; D003622:Dapsone