Functional bladder capacity and urodynamics in males with nocturia

Area of Science:

• Urology
• Nephrology
• Gerontology

Background:

• Nocturia in males with lower urinary tract symptoms (LUTS) has varied causes, including nocturnal polyuria or preserved circadian urine output.
• Understanding the interplay between urine production and bladder capacity is key to managing nocturia.

Purpose of the Study:

• To investigate the causes of nocturia in males with LUTS, differentiating between nocturnal polyuria and diminished functional bladder capacity (FBC).
• To assess the role of circadian urine production and FBC in nocturia among LUTS patients.

Main Methods:

• Utilized 7-day frequency/volume (FV) charts in an outpatient setting.
• Correlated daytime voided volumes from urodynamic studies with nighttime FBC from FV charts.
• Analyzed diurnal variation in FBC and its relationship with nocturia in LUTS patients and controls.

Main Results:

• Patients with nocturnal polyuria and controls showed diurnal FBC variation with higher nighttime values.
• Patients without nocturnal polyuria had no diurnal FBC variation and lower day/nighttime values.
• Nocturia volumes correlated with daytime FBC; voided volumes correlated with nighttime FBC.
• Nocturia in LUTS patients was caused by nocturnal polyuria (10/23) or diminished nighttime FBC (13/23).

Conclusions:

• Nocturia in males with LUTS is often due to a mismatch between nocturnal urine production and nighttime FBC.
• This pathophysiology is similar to that of nocturnal enuresis.
• Evaluating circadian urine production and FBC is essential for assessing male LUTS patients with nocturia.