• Sean van Diepen, Alan Sobey, Richard Lewanczuk, Surita Sidhu, Mohamad Zibdawi, and John C Mullen.
• Divisions of Critical Care and Cardiology, University of Alberta, Edmonton, AB, Canada, sv9@ualberta.ca.
• Can J Anaesth. 2013 Nov 1;60(11):1085-8.

PurposeIn 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.Clinical FeaturesA 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).ConclusionIn 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.

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