Critical rebound methemoglobinemia after methylene blue treatment: case report.
A 39-year-old man developed significant methemoglobinemia after receiving benzocaine spray; he was treated appropriately with intravenous methylene blue. The patient's methemoglobin levels decreased, but this was followed by a critical rebound phenomenon to levels frequently considered near fatal. After further treatment with methylene blue, the patient's methemoglobin levels returned to normal. Clinicians need to be aware that a decreasing level of methemoglobin does not necessarily indicate that a crisis has passed and that further monitoring and treatment may be indicated.
Fitzsimons
Michael G
MG
Harvard Medical School, Departments of Anesthesia and Critical Care, Massachusetts General Hospital, Boston, Massachusetts 02114, USA. mfitzsimons@partners.org
Gaudette
Ronald R
RR
Hurford
William E
WE
D000328:Adult; D000779:Anesthetics, Local / Q000009:adverse effects; D001566:Benzocaine / Q000009:adverse effects; D006801:Humans; D008297:Male; D008708:Methemoglobinemia / Q000139:chemically induced*; D008751:Methylene Blue / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use
D000779:Anesthetics, Local; D008751:Methylene Blue; D001566:Benzocaine