Kayexalate Colitis: Correlation of the Pathological, Clinical and Pharmacological Features

Kayexalate, a common therapy for hyperkalemia, has been implicated in bowel necrosis including cases of perforation and death. Despite the seriousness of this effect, the literature describing the pathological and clinical features is very limited, and the dose and time course of the Kayexalate administration is not well characterized. The goal of this study is to assess the association between Kayexalate and the development of bowel necrosis and to describe all cases of Kayexalate-associated injury encountered at our health system. Design: A retrospective review of electronic medical records was performed in a large health system over a six year period (2012- 2018). Clinical record was reviewed for all patients in whom Kayexalate crystals were identified in their pathology report. Patients were tabulated to analyze clinicopathological features, demographics and patient risk factors. Pharmacy records were reviewed to confirm drug administration and to assess time and number of doses. Results: 48 patients were identified to have Kayexalate crystals in their pathology report. Only 16 of those had drug administration confirmed in the pharmacy records, (Table 1). 14 were surgical cases and 2 were autopsy cases. The surgical cases all had ileocolonic involvement, while the autopsy cases were both upper GI. All but two cases had Kayexalate-associated injury, including ischemic-colitis pattern, active colitis, and ulcer. In the remaining two, both with multiple doses, crystals were associated with a tubular adenoma and gastric mucosa with no associated injury, respectively. The last dosage was within five days of procedure in 13 cases (80%). Conclusions: These findings highlight the complexity of Kayexalate diagnosis. Crystal deposition in the GI tract is sometimes a nonpathogenic, incidental finding. The 32 cases in which crystals resembling Kayexalate were found without record of drug administration raise the possibility that there may be unknown drug mimics. Autopsy data is a useful, under-recognized source of information that can be used to determine whether a finding can exist in asymptomatic patients. In our cases, crystals were more likely to be pathogenic when found in the colon and less likely when found in the stomach, but the number of doses did not correlate with extent of injur