title: Methemoglobinemia as a cause of coma.
abstract: A 50-year-old man presented to the emergency department in a coma with fixed and dilated pupils. Skin and mucous membranes were noted to be an ashen grey color. Initial vital signs were blood pressure of 104/70 mm Hg; pulse, 110; and respirations, 12. Initial arterial blood gases were pH of 7.25; PaCO2, 26.6 mm Hg; PaO2, 22.1 mm Hg; oxygen saturation, 15.2%; and methemoglobin level, 81.5%. Venous and arterial blood samples were chocolate brown, and it was noted that the color did not change when 100% oxygen was bubbled through the blood. Methylene blue 140 mg was given intravenously, and the patient gradually became more responsive. He was discharged three days later with no neurologic deficits. A comprehensive literature search revealed no reported cases of complete patient recovery with this high a methemoglobin level.
authors.affiliation: Department of Emergency Medicine, Winchester Medical Center, Virginia 22601.
authors.forename: L
authors.initials: L
authors.lastname: Caudill
authors.forename: J
authors.initials: J
authors.lastname: Walbridge
authors.forename: G
authors.initials: G
authors.lastname: Kuhn
mesh_terms: D003128:Coma / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008708:Methemoglobinemia / Q000097:blood / Q000150:complications* / Q000188:drug therapy; D008751:Methylene Blue / Q000008:administration & dosage / Q000627:therapeutic use; D008875:Middle Aged
chemical_list: D008751:Methylene Blue