title: Dapsone-induced methhaemoglobinaemia: a source of diagnostic confusion.
abstract: Arterial desaturation as measured using pulse oximetry may not reflect cardiorespiratory disease; other possible causes, including certain drugs, should be sought. Within the literature, examples exist of dapsone-induced methaemoglobinaemia causing diagnostic confusion, particularly where respiratory disease is a feature. Few cases have been reported that demonstrate the potential of relatively low levels of methaemoglobinaemia to upset pulse oximetry readings. We describe three examples of dapsone-induced methaemoglobinaemia emphasising the potential for low-grade methaemoglobinaemia to cause diagnostic confusion. Widespread use of the pulse oximeter indicates this problem may occur more regularly, hence there is a need for increased awareness.
authors.affiliation: Department of Haematology, Royal Group of Hospitals Trust, Belfast, UK.
authors.forename: D
authors.initials: D
authors.lastname: Craig
authors.forename: I S
authors.initials: IS
authors.lastname: Cadden
authors.forename: W P
authors.initials: WP
authors.lastname: Gormley
authors.forename: M S
authors.initials: MS
authors.lastname: Riley
authors.forename: F G
authors.initials: FG
authors.lastname: Jones
authors.forename: M F
authors.initials: MF
authors.lastname: McMullin
mesh_terms: D000293:Adolescent; D000328:Adult; D003622:Dapsone / Q000009:adverse effects*; D003937:Diagnosis, Differential; D005260:Female; D005493:Folic Acid Antagonists / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008708:Methemoglobinemia / Q000139:chemically induced* / Q000175:diagnosis; D008875:Middle Aged; D010092:Oximetry; D016896:Treatment Outcome
chemical_list: D005493:Folic Acid Antagonists; D003622:Dapsone