Investigators recently reviewed International Continence Society (ICS) standards in nocturnal lower urinary tract function to provide clinicians with a practical guide for evaluating nighttime urination.
Nocturia is technically a storage symptom, characterized by awakening to void, Hashim Hashim, MD, and Marcus J. Drake, MD, of Bristol Urological Institute in the UK, stated in Neurourology and Urodynamics. Enuresis differs from nocturia in that bedwetting occurs when the person is asleep.
To identify nocturia, clinicians should assess patient symptoms. To rule out external disturbances, ask the reason for waking. For better management, ICS emphasizes assessing bother in addition to symptom severity. Use the International Consultation on Incontinence Questionnaires (ICIQ) or similar symptom scores.
A 3-day frequency/volume chart or bladder diary (showing drinking volume, urine output, and bladder sensation scores) is an important approach to identifying possible contributors. Polyuria over 24 hours might indicate diabetes, salt loss, or another medical problem. Excessive production and voiding of urine at night signals nocturnal polyuria, which is defined as nightly voided volume exceeding 20% or 33% of 24-hour volume in younger and older adults (65 years or more), respectively. Obstructive sleep apnea and peripheral edema are known contributors to nocturnal polyuria. Higher bladder sensation scores might indicate lower urinary tract dysfunction. When a patient reports anxiety, restless legs, nightmares, or sleepwalking, suspect a sleep disorder.
Hashim H and Drake MJ. Basic concepts in nocturia, based on international continence society standards in nocturnal lower urinary tract function. Neurourol & Urodyn. 2018;37:S20–S24.