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Terminology, epidemiology, etiology, and pathophysiology of nocturia
Philip v. Kerrebroeck and K-E. Andersson
Neurourology and Urodynamics, Volume 33, Issue S1, Pages S2-S5, April 2014
(Guest Expert: Stephan Madersbacher, DM, Phd, FEBU, Fellow of the European Board of Urology, Generalsekretär der Österr. Gesellschaft für Urologie)
Nocturia is the most prevalent single component of lower urinary tract symptoms. If nocturia is defined as >1 void/night about 50% of individuals older than 20yrs are affected. Beyond the 6th decade of life approximately 20% of men and women have a nocturia >2, which is considered as a clinically more meaningful cut-off. The demographic changes in upcoming decades and the morbidity and mortality of nocturia explain the increasing interest in this symptom. Despite the clear age-dependency, up to 20% of adults aged 20-30yrs of age have two or more nocturnal voids in whom nocturia has a significant burden on daytime activity. Despite these impressive figures nocturia remains - as correctly stated Van Kerrebroeck and Andersson - an underreported, understudied, and very infrequently recognized problem in adults.
Nocturia can be related to five distinct pathomechanisms, which may occur isolated or in various combinations: an overall increase of urine production (24hr polyuria), an increase of urine production only at night (nocturnal polyuria (NP)), a permanent or only nocturnal reduced bladder capacity, any primary or secondary sleep disorder and circadian clock disorders. All these four pathomechanisms require a further diagnostic work-up, the consideration of specific differential diagnoses and underlying pathologies and an individualized management. The cornerstone of the diagnostic work-up of individuals with nocturia is a frequency volume chart over 1-2 days.
Current research centres on the natural history of nocturia (suggesting that nocturia has an undulating course in many affected individuals), novel diagnostic approaches (such as renal function profiles or the innovative biomarker copeptin) and the implementation of an individualized therapeutic approach.
Nocturia remains one of the most important bothersome urological symptoms. Urologists and general practitioners have to be aware of the various pathomechanisms and the state-of-the-art work-up as outlined in the well-written review of Van Kerrenbroeck and Andersson recently published in Neurourology and Urodynamics.
Nocturia, awaking from sleep to void, has a negative impact on health and well-being. Nocturia affects men and women and is more prevalent among the elderly. More than two nocturnal voids is considered to be a clinically meaningful threshold associated with significant negative outcomes for health and well-being, and the timing of awakening has a significant bearing on the negative consequences of nocturia. Several serious underlying pathophysiologic conditions may be associated with nocturia. A thorough history and assessment of number and times of voids, void volume, and fluid intake is essential for determining the etiology of a patient's nocturia. With data obtained from the frequency-volume chart (FVC), which is used to collect quantitative voiding data, a patient's nocturia may be classified as global polyuria, nocturnal polyuria, reduced bladder capacity, or a combination of these categories. Global polyuria is defined as 24-hr urinary output that exceeds 40 ml/kg body weight and results in increased 24-hr urinary frequency. Nocturnal polyuria is defined as more than 20% of daily urine output at night in young patients and more than 33% in elderly patients. Reduced bladder capacity may be a result of idiopathic or neurogenic detrusor overactivity, bladder outlet obstruction, or reduced nocturnal bladder capacity. The pathophysiology underlying the findings of the FVC falls into five main categories: global polyuria, nocturnal polyuria, reduced bladder capacity, sleep disorders, and circadian clock disorders. This review discusses the epidemiology, etiology, and pathophysiology of nocturia.
Neurourol. Urodynam. 33:S2–S5, 2014. © 2014 Wiley Periodicals, Inc.