Oral potassium overdose: a case series

Oral potassium poisoning: a retrospective review of the National Poison Data System 2010-2021

INTRODUCTION

Oral potassium poisoning can be life-threatening. The study aimed to describe patterns of oral potassium poisoning in adult and pediatric populations and characterize its clinical presentation and management as reported by United States poison centers.

METHODS

This is a retrospective review of the National Poison Data System from 1 January 2010 through 30 June 2021. We descriptively analyzed cases involving single substance, oral potassium salts. In a second step, we requested a subset of case-specific narratives for cases that resulted in major outcome or death, as well as cases where patients received any of the following therapies: whole bowel irrigation, sodium bicarbonate, calcium, insulin or hemodialysis. We classified hyperkalemia by expected toxicity: mild (peak potassium concentration <6.5 mEq/L), moderate (peak potassium concentration 6.5 to <8 mEq/L) or severe (peak potassium concentration ≥ 8mEq/L).

RESULTS

The National Poison Data System included 1,820 cases, 52.3 percent being adults. Among adult cases, 20% (n = 189) resulted in a moderate effect, major effect or death. Among pediatric cases aged <10 years, all exposures were unintentional. Analysis of 49 case narratives showed a median peak potassium concentration of 7.1 mEq/L (interquartile range 5.4-8.6) and a moderate correlation with the dose ingested (r = 0.66). Severe hyperkalemia was associated with QRS complex widening (P < 0.001), peaked T-waves (P = 0.001), and neurological symptoms (P = 0.04). Whole bowel irrigation was associated with mild hyperkalemia (P = 0.011), and hemodialysis was associated with severe hyperkalemia (P < 0.001).

DISCUSSION

Analysis of data showed that therapy to promote intracellular shift of potassium is the mainstay of management of oral potassium poisoning, followed by hemodialysis.

LIMITATIONS

Poison center data are susceptible to reporting bias. National Poison Data System data are affected by completeness and accuracy of reporting from health care providers and the lay public.

CONCLUSIONS

Single substance, oral potassium poisoning, reported to United States poison centers, is mostly unintentional and rarely results in hyperkalemia.

Unexpectedly Prolonged Serotonin Syndrome and Fatal Complications Following a Massive Overdose of Paroxetine Controlled-Release

Symptoms caused by a selective serotonin reuptake inhibitor (SSRI) overdose are often mild and can be managed with supportive care and close monitoring, even when complicated by serotonin syndrome. There are limited pharmacokinetic data regarding massive overdoses of paroxetine, and the severity of an SSRI overdose is likely to be underestimated. We describe a fatal case of severe serotonin syndrome and acute respiratory distress syndrome (ARDS) following an overdose of controlled-release paroxetine. A 53-year-old male with depression presented with altered consciousness. He had ingested controlled-release paroxetine along with other medications. On arrival, he had ocular flutter and myoclonus, and blood examinations revealed acute kidney injury and rhabdomyolysis, which suggested serotonin syndrome. Computed tomography (CT) showed pharmacobezoars in the esophagus and stomach. Symptoms of serotonin syndrome and hypotension persisted despite administration of high doses of vasopressors with endotracheal intubation. We performed endoscopic decontamination to remove pharmacobezoars from the stomach. Finally, he developed severe ARDS and died due to respiratory failure on day 23. Sequential serum concentrations of paroxetine were 5.38 µg/mL at admission and 3.21 µg/mL on day 7, both above lethal levels. This case highlights the potential for fatal complications and prolonged toxicity in the case of a massive overdose of controlled-release paroxetine. We should recognize that such an overdose may be life-threatening and should consider aggressive interventions including endoscopic decontamination. A better understanding of the pharmacokinetics of a massive SSRI overdose would be helpful for optimal management.

Detection of Fatal Potassium Overdose: A Case Report and Review of the Literature

Potassium overdose usually occurs accidentally, but potassium is also used for judicial executions, assisted death, and, rarely, suicides. In addition to exogenous overdose, various drugs, and renal failure, diabetic ketoacidosis can cause hyperkalemia. Potassium tablets are used in most cases of suicidal potassium overdose. Suicide by intravenous administration of potassium is rare but usually fatal. The author reports a rare case of suicide with potassium infusion. Autopsy and histology findings, along with post-mortem biochemical analysis of different body fluids and fluid from the infusion set, are reported. Previously published reports of potassium overdose were reviewed, and the detection possibilities of potassium overdose are discussed. The detection possibilities of lethal hyperkalemia are very limited since hyperkalemia produces only nonspecific autopsy and histology findings. Post-mortem potassium concentrations are not indicative of ante-mortem potassium concentrations; therefore, post-mortem biochemical analysis has limited value in determining potassium overdose. The best way to prove potassium overdose is via the collection and analysis of circumstantial evidence.