Objective: Sodium polystyrene sulfonate (kayexalate) is a cation-exchange resin given enterally for the treatment of hyperkalemia. Aspiration of this material is a rare occurrence, but when visualized in the alveolus, it has a characteristic microscopic appearance that is virtually diagnostic. In two cases, recognition of the characteristic morphology of the foreign material raised the question of sodium polystyrene sulfonate.
Design: We used infrared spectroscopy to demonstrate the presence of this material in lung biopsies of two patients by identifying foreign body particles. Histories of the patients were reviewed for exposure to sodium polystyrene sulfonate.
Setting: Two lung specimens were referred to the Armed Forces Institute of Pathology with an unknown foreign material identified within the air spaces.
Patients: The lung biopsies were from two children, one postterm female infant who died at 3 days of life and a 4-year-old girl who underwent lung biopsy during surgical repair for tetralogy of Fallot. Both patients had received sodium polystyrene sulfonate previously for control of hyperkalemia.
Results: The lung specimens showed characteristic basophilic, amorphous foreign material in airspaces on histologic sections. The identity of this material was confirmed by Fourier transform infrared microspectrophotometry.
Conclusions: To our knowledge, we report the first two cases of sodium polystyrene sulfonate aspiration in children. This material has a distinctive morphologic appearance on histologic sections, and its identity can be confirmed by Fourier transform infrared microspectrophotometry.