Calcium Polystyrene Sulfonate Crystal-related Airway Obstruction.

An 83-year-old man diagnosed with multiple myeloma presented with renal failure and hyperkalemia. The patient was treated with calcium polystyrene sulfonate (CPS: kalimate) for hyperkalemia. On the 10th day after starting CPS, airway obstruction due to the presence of a mass was observed, and the patient died on that same day. Autopsy revealed that the mass was located between the trachea and epiglottis and it was determined to consist of CPS-related mosaic crystals. There was a protrusion within the trachea surrounding the CPS crystals, inflammatory cells, and granulation tissue. This case suggests that CPS is associated with not only gastrointestinal complications, but also with airway complications.