Severe Hyponatremia From Water Intoxication Associated With Preparation for a Urine Flow Study

Abstract

To discuss the natural history and impact of hyponatremia secondary to water intoxication in the setting of a urine flow study. Case report and literature review. An 82 year old male developed severe hyponatraemia following preparation for a urine flow study as part of ongoing follow up of lower urinary tract symptoms. He was admitted to an intensive care unit after developing acute confusion with a sodium of 114 mmol/L and discharged after his symptoms improved with slow correction of his sodium level. There are few reports in the literature of this event and no consensus guidelines on safe preparation for flow studies or other imaging modalities requiring pre-procedural fluid hydration. Patients with medications or conditions predisposing to hyponatremia are at higher risk of adverse events when overhydration occurs. Hyponatremia is a major adverse outcome of urine flow studies. Wider reporting of this condition is required to improve awareness of its effects and develop consensus guidelines on preventing its occurrence.

The influence of water intake on waiting time prior to uroflowmetry: a prospective, randomized, double-blind trial

“…Some reports have been published about water intoxication before flow study caused severe hyponatremia and seizure. 9,11,12 In this study, water intake of 300-500 ml was safe and did not cause any complains from patients. We suggest patients should take more than 500 ml of water prior to uroflowmetry.…”

“…There are no consensus guidelines on safe preparation or imaging modalities for pre-procedural fluid hydration. 9 Patients are usually asked to drink plenty of water to achieve a full bladder and wait until they have a desire to urinate. 7 The disadvantage of this method is some patients feel uncomfortable with a full bladder, and some other patients have their bladder not fully filled for uroflowmetry study.…”