Calcium polystyrene sulfonate–induced colitis: advanced characterization of crystal nature with infrared spectroscopy

Classical potassium binders are used in the treatment of hyperkalemia and are widely associated with gastrointestinal side effects, with crystal colonic injury being rare but potentially fatal. In this report, we describe the case of an 82-year-old male with hyperkalemia and calcium polystyrene sulfonate crystal–associated colonic necrosis. Traditionally, this diagnosis has relied on the examination of crystal morphology and polarization through microscopy. Our study enhances crystal identification by incorporating an analysis of the physical characteristics of the crystals using infrared spectroscopy. This is the first description, to our knowledge, of the calcium polystyrene sulfonate infrared spectrum.