Thinking beyond the bladder: antidiuretic treatment of nocturia

Nocturia is a bothersome and highly prevalent urological condition characterised by the need to wake to void at night. Contrary to popular misconception, nocturia is equally common in men and women, and although its prevalence increases with age, a significant proportion of younger people are also affected. Nocturia leads to repeated fragmentation of sleep and consequently to a serious decline in daytime functioning and in overall quality of life and health. As such, its impact should not be underestimated by clinicians. Traditionally, nocturia has been regarded as a symptom of benign prostatic enlargement and/or overactive bladder syndrome, with treatment therefore directed towards increasing the capacity of the bladder to hold urine. Such treatments have proven largely ineffective in many patients, likely because nocturnal polyuria (NP), a condition that results in overproduction of urine at night, has been found to be present in the majority of nocturia patients. As such, the traditional belief that nocturia is attributable to some other underlying pathological factors, is now being replaced by the acknowledgment that it can be a distinct clinical entity with specific pathogenesis. Frequency-volume charts are an invaluable tool, recommended for routine use in clinical practice, to determine whether nocturia is a result of excessive urine production at night, or of small voided volumes (indicating bladder storage problems), or indeed a combination of these factors. Given the specific antidiuretic action of desmopressin, a synthetic analogue of the body's own antidiuretic hormone, it should be considered as first-line therapy for patients with nocturia where NP is present.