Oral potassium overdose: a case series

Severe toxicity from ingestions of oral sustained-release potassium is rare. While acute hyperkalaemia requires urgent intervention given the risk of cardiac toxicity, there is a lack of clinical consensus on optimal management. The aim of this study was to characterise the clinical manifestations of acute potassium overdose and its management approach.

This is a retrospective case series of patients presenting following oral potassium overdose of ≥6000mg between January 2009 and December 2020 in Queensland, Australia as recorded in the state's Poisons Information Centre database and a tertiary Clinical Toxicology Unit database. Patients were identified from prospective databases maintained by both units and data were extracted from these in addition to medical records.

Thirteen presentations in eleven patients occurred in the twelve-year period. The median age was 35 years (range 14-55 years). The median dose ingested was 6.4 mmol/kg (range 0.9-30.8 mmol/kg). Severe hyperkalaemia >7mmol/L occurred in five patients, four with ingestions ≥60,000mg. All patients with hyperkalaemia received multiple modes of intracellular potassium shifting therapy. Four patients had endoscopic removal of pharmacobezoars. One also underwent whole bowel irrigation. Three presentations were managed with haemodialysis. All patients were discharged home with a median length of stay of 20 h.

Aggressive medical therapy to shift potassium into cells appears to be the mainstay of treatment in patients with normal renal function. Early decontamination may limit peak potassium concentrations. It is unclear if haemodialysis provides significant additional benefit in patients with normal renal function.