Detrusor Overactivity Persisting at Night and Preceding Nocturia in Patients With Overactive Bladder Syndrome: A Nocturnal Cystometrogram and Polysomnogram Study

PurposeNocturia, a common symptom of overactive bladder syndrome, is associated with substantial adverse consequences and yet its pathophysiology has hardly been studied and the capacity to treat it remains limited. We established methods to study the physiology of overactive bladder associated nocturia and better understand this phenomenon.Materials and MethodsWe recorded simultaneous, time aligned, nocturnal cystometrogram and polysomnogram data during a single night at a sleep laboratory in 9 patients with overactive bladder and detrusor overactivity on daytime cystometrogram, in 10 patients with insomnia and in 5 healthy controls.ResultsWe safely recorded simultaneous polysomnography/nocturnal cystometrography data accurately during the sleep period. Nocturnal detrusor overactivity occurred significantly less often in patients with insomnia and controls than in patients with detrusor overactivity plus overactive bladder (p = 0.02) and only in the 10 minutes before nocturia events in the latter (0%, 0% and 67%, respectively, p = 0.002). Patients with detrusor overactivity plus overactive bladder were awake for a shorter period before nocturia events (p <0.001) and had a greater percent of nocturia associated awakenings. Patients with insomnia had more awakenings unrelated to nocturia. Nocturnal polyuria, another cause of nocturia, was not significantly associated with nocturnal detrusor overactivity.ConclusionsSleep and bladder pressure physiology may be safely monitored during the sleep period accurately. Nocturnal detrusor overactivity occurs in association with nocturia in most patients with detrusor overactivity plus overactive bladder, does not generally occur during sleep and is not due to sleep disturbance or nocturnal polyuria. This study may provide a foundation for research on overactive bladder related nocturia pathophysiology and treatment.