title: Methylene blue for clinical anaphylaxis treatment: a case report.
abstract: OBJECTIVE
  Nitric oxide has a pathophysiological role in modulating systemic changes associated with anaphylaxis. Nitric oxide synthase inhibitors may exacerbate bronchospasm in anaphylaxis and worsen clinical conditions, with limited roles in anaphylactic shock treatment. The aim here was to report an anaphylaxis case (not anaphylactic shock), reversed by methylene blue (MB), a guanylyl cyclase inhibitor.
  
  
  METHODS
  A 23-year-old female suddenly presented urticaria and pruritus, initially on her face and arms, then over her whole body. Oral antihistamine was administered initially, but without improvement in symptoms and signs until intravenous methylprednisolone 500 mg. Recurrence occurred after two hours, plus vomiting. Associated upper respiratory distress, pulmonary sibilance, laryngeal stridor and facial angioedema (including erythema and lip edema) marked the evolution. At sites with severe pruritus, petechial lesions were observed. The clinical situation worsened, with dyspnea, tachypnea, peroral cyanosis, laryngeal edema with severe expiratory dyspnea and deepening unconsciousness. Conventional treatment was ineffective. Intubation and ventilatory support were then considered, because of severe hypoventilation. But, before doing that, based on our previous experience, 1.5 mg/kg (120 mg) bolus of 4% MB was infused, followed by one hour of continuous infusion of another 120 mg diluted in dextrose 5% in water. Following the initial intravenous MB dose, the clinical situation reversed completely in less than 20 minutes, thereby avoiding tracheal intubation.
  
  
  CONCLUSIONS
  Although the nitric oxide hypothesis for MB effectiveness discussed here remains unproven, our intention was to share our accumulated cohort experience, which strongly suggests MB is a lifesaving treatment for anaphylactic shock and/or anaphylaxis and other vasoplegic conditions.
authors.affiliation: Department of Surgery and Anatomy, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, CEP 14015-120, Brazil.
authors.forename: Janine Moreira
authors.initials: JM
authors.lastname: Rodrigues
authors.forename: Antonio
authors.initials: A
authors.lastname: Pazin Filho
authors.forename: Alfredo José
authors.initials: AJ
authors.lastname: Rodrigues
authors.forename: Walter Vilella de Andrade
authors.initials: WV
authors.lastname: Vicente
authors.forename: Paulo Roberto Barbosa
authors.initials: PR
authors.lastname: Evora
mesh_terms: D000328:Adult; D000707:Anaphylaxis / Q000188:drug therapy* / Q000209:etiology; D000799:Angioedema / Q000209:etiology; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007040:Hypoventilation / Q000209:etiology; D007275:Injections, Intravenous; D008751:Methylene Blue / Q000627:therapeutic use*; D011693:Purpura / Q000209:etiology
chemical_list: D004791:Enzyme Inhibitors; D008751:Methylene Blue