Green Urine after Intragastric Balloon Placement for the Treatment of Morbid Obesity

Background: The intragastric balloon is filled with saline and methylene blue dye, to detect balloon deflation early and prevent bowel obstruction, by monitoring the patient's urine for changes in color. Methods: An intragastric balloon filled with 590 ml of saline plus 10 ml of methylene blue was endoscopically placed under sedation in a 22-year-old man with morbid obesity (BMI 42 kg/m²). 3 days later, the patient's urine changed to dark green, and, suspecting a leaking balloon, endoscopy was repeated under sedation. Results: No signs of balloon deflation were seen, and the urine returned to normal color. The next day, the urine turned green again. 7 days later, the urine discoloration finally disappeared. Conclusion: Propofol, a sedative commonly used by anesthesiologists during endoscopic procedures, is known to have several side-effects, and urine discoloration is one of them, albeit rare. This benign side-effect must be known to obesity surgeons to avoid pointless medical expenditure, unnecessary balloon removal and distress for patients and clinicians.