Reduced bladder capacity without daytime voiding symptoms with nocturnal enuresis.

BACKGROUND: This study aimed to evaluate the prevalence of monosymotomatic nocturnal enuresis (MSNE) with reduced bladder capacity in children with primary nocturnal enuresis (NE) and to suggest treatment outcomes. METHODS: This study retrospectively evaluated 54 children (30 males, 24 females; median age: 8; range: 5-14) who were newly diagnosed with primary NE from November 2017 to October 2019. Reduced bladder capacity in MSNE was defined when a patient's maximal voided volume (MVV) from his or her voiding diary was 75% or less than estimated functional bladder capacity ([age + 1] x 30 mL) for his or her age and there were no daytime lower urinary tract symptoms (LUTS) as assessed using history taking and questionnaires. RESULTS: Nineteen (35.2%) of 54 children with newly diagnosed primary NE did not report daytime LUTS. Fifteen children (27.8%) had a reduced bladder capacity and were prescribed anticholinergic or beta-3 agonist. After three months of medication, MVV significantly increased from 117.5 mL to 183.3 mL (P = 0.010), but frequency showed no significant change from 5.7 to 4.9 times a day. Improvement in enuresis occurred completely and partially in 41.7% and 25% of participants, respectively. CONCLUSIONS: The prevalence of reduced bladder capacity without daytime voiding symptoms was relatively high as 27.8% in children newly diagnosed with primary NE. In primary MSNE, reduced bladder capacity should be investigated using a frequency-volume chart in addition to thorough history taking or questionnaires. Anticholinergics or beta-3 agonists for MSNE with reduced bladder capacity are effective at increasing the bladder capacity of these patients.