This is the second part to a two-part case (scroll down to see the first part).
Unfortunately, the patient described in the last case fails to follow up with a doctor. He finally presents with intractable coughing and recurrent pneumonias. He is intubated and a percutaneous gastrostomy tube is placed for nutrition. He continues to get recurrent pneumonias until finally a diagnostic procedure is done involving methylene blue in the tube feeds.
Challenge: What is the diagnostic procedure? What do you expect?