Etiology and symptoms of severe hypokalemia in emergency department patients.

OBJECTIVES: To investigate the prevalence, etiology, and symptoms of severe hypokalemia in patients presenting to the emergency department.

METHODS: In this retrospective, cross-sectional analysis, we included all patients who received measurement of serum potassium between April 2008 and 31 March 2011 at the emergency department to calculate the prevalence rate for hypokalemia. Of all patients with a serum potassium below 2.6 mmol/l (severe hypokalemia), we performed a detailed review of the patients' charts from the emergency department and the chart of the subsequent hospitalization. We identified ECG changes attributable to hypokalemia from the ECGs performed in the emergency department.

RESULTS: During the study period, measurements of serum potassium for a total of 43 805 patients were performed. Of these patients, 4826 (11%) had hypokalemia (potassium <3.5 mmol/l) at presentation. Fifty-three (1%) patients with severe hypokalemia could be identified. Twenty-six (49%) patients were symptomatic, with weakness and muscle pain being the most common symptoms. Twenty (69%) patients had ECG changes with the presence of a U wave, followed by ST segment depression and ventricular extrasystoles. Malnutrition and use of diuretics were the main causes of severe hypokalemia.

CONCLUSION: Hypokalemia is common in the emergency department. Severe hypokalemia is often symptomatic and more than two-thirds of patients show ECG changes.