title: A case of acute respiratory distress syndrome responsive to methylene blue during a carcinoid crisis.
abstract: OBJECTIVE
  In a carcinoid crisis, numerous vasoactive agents, such as bradykinin precursors, serotonin, and histamine, are secreted by tumour cells. Bradykinin has been shown to increase pulmonary vascular permeability and hypotension in animal models; however, little is known about its in vivo effects or targeted pharmacotherapy in a carcinoid crisis. We describe a case of acute respiratory distress syndrome (ARDS) in a carcinoid crisis refractory to conventional antiserotonin and antihistamine therapies.
  
  
  METHODS
  A 56-yr-old male with known liver metastases and previous resection of a small intestinal carcinoid tumour in 1991 underwent successful tricuspid and pulmonary valve replacements. On postoperative day 10, he developed hypotension, a fever, leukocytosis, and flushing. His hypotension was treated with a 200 μg octreotide iv bolus followed by a 150 μg·hr(-1) infusion, vasopressin, norepinephrine, and hydrocortisone. He also required tracheal intubation for ARDS (Pa02:FI02 ratio 96). After 72 hr of broad spectrum antibiotics and no clinical improvement, antiserotonin and antihistamine therapies were augmented with cyproheptadine, ranitidine, and serial octreotide boluses with an infusion of 1,500 μg·hr(-1). These interventions improved his oxygenation (Pa02:F i 02 ratio 162) and reduced his norepinephrine requirements. Following a methylene blue bolus (1 mg·kg(-1)) and 12-hr infusion (0.5 mg·kg(-1)·hr(-1)), all vasopressors were discontinued and his oxygenation improved (Pa02:F i 02 ratio 297).
  
  
  CONCLUSIONS
  In a patient with a carcinoid crisis and ARDS refractory to conventional therapies, substantial hemodynamic and oxygenation improvements were observed following methylene blue administration. This case highlights the potential pathophysiologic role of bradykinin and methylene blue as an adjunct therapeutic option in carcinoid crises.
authors.affiliation: Divisions of Critical Care and Cardiology, University of Alberta, Edmonton, AB, Canada, sv9@ualberta.ca.
authors.forename: Sean
authors.initials: S
authors.lastname: van Diepen
authors.forename: Alan
authors.initials: A
authors.lastname: Sobey
authors.forename: Richard
authors.initials: R
authors.lastname: Lewanczuk
authors.forename: Gurmeet
authors.initials: G
authors.lastname: Singh
authors.forename: Surita
authors.initials: S
authors.lastname: Sidhu
authors.forename: Mohamad
authors.initials: M
authors.lastname: Zibdawi
authors.forename: John C
authors.initials: JC
authors.lastname: Mullen
mesh_terms: D001920:Bradykinin / Q000378:metabolism; D002276:Carcinoid Tumor / Q000473:pathology* / Q000601:surgery; D019918:Heart Valve Prosthesis Implantation / Q000379:methods; D006801:Humans; D007414:Intestinal Neoplasms / Q000473:pathology* / Q000601:surgery; D007421:Intestine, Small / Q000473:pathology / Q000601:surgery; D008113:Liver Neoplasms / Q000556:secondary; D008297:Male; D008751:Methylene Blue / Q000627:therapeutic use*; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D012128:Respiratory Distress Syndrome / Q000188:drug therapy* / Q000209:etiology; D014662:Vasoconstrictor Agents / Q000627:therapeutic use
chemical_list: D014662:Vasoconstrictor Agents; D010100:Oxygen; D001920:Bradykinin; D008751:Methylene Blue