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Asymptomatic benzocaine spray–induced methaemoglobinaemia in preoperative sedation for oesophagogastroduodenoscopy
  1. Abdullah Jarrah1,2,
  2. Ali Al Sbihi1,2,
  3. Nouraldeen Manasrah1,2 and
  4. Sarah Alqasem3
  1. 1Internal Medicine, Sinai Grace Hospital, Detroit, Michigan, USA
  2. 2Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan, USA
  3. 3Emergency/Internal Medicine, Luzmila Hospital, Amman, Jordan
  1. Correspondence to Dr Ali Al Sbihi; aalsbihi{at}


Methaemoglobinaemia is defined as elevated methaemoglobin in the blood which is characterised by conversion of some of the reduced ferrous iron elements [Fe2+] to the oxidised ferric [Fe3+] form which does not have capacity to bind and transport oxygen resulting in functional anaemia. Causes can be genetic mutations or acquired by medications such as dapsone, nitrates or benzocaine. Benzocaine is currently being used as a topical anaesthetic agent before certain procedures. We report a case of benzocaine spray–induced methaemoglobinaemia in a patient who underwent oesophagogastroduodenoscopy for evaluation of upper gastrointestinal bleeding.

  • Endoscopy
  • Haematology (incl blood transfusion)
  • Adult intensive care
  • Unwanted effects / adverse reactions

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  • Contributors AJ did majority of editing, assigned roles to coauthors, obtained the consent from the patient’s sister and addressed the article after reviewers' comments. AAS provided efforts in the discussion part, proofreading the case presentation as well because he took care of the patient during admission and wrote cover letter. NM helped in editing and review, and made sure that references are accurate and another doctor who took care of the patient. SA worked on learning points and reviewed the manuscript to make sure that vocabulary and grammar are accurate again.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.