Functional Bladder Disorders in Children: An overview and classification

Functional bladder disorders (FBDS) in children represent a spectrum of conditions characterized by abnormal storage or emptying of urine that are not attributable to any underlying anatomical abnormalities or neurological deficits. These conditions significantly impact a child's daily life. Functional bladder disorders (FBDs) are defined by the presence of a functional disruption in the coordinated interplay between the bladder (the detrusor muscle responsible for storing and expelling urine) and the urethral sphincters (muscles that control the outflow of urine), all under the regulation of the nervous system. The primary symptoms of FBDs include: Urgency, Incontinence(Stress Incontinence, Urge Incontinence), Nocturnal Enuresis (Bedwetting), Frequency, Urinary Retention, Poor Detrusor Contraction, and Inappropriate Sphincter Activity. Classification: The International Children's Continence Society (ICCS) categorizes pediatric FBDs into several primary groups: Overactive Bladder (OAB): This is one of the most common FBDs in children. It is characterized by the symptom of urgency, which may or may not be accompanied by incontinence. The underlying pathophysiology involves involuntary detrusor contractions that occur during the bladder filling phase, leading to the sudden, strong urge to urinate. Underactive Bladder (UAB): In contrast to OAB, UAB is characterized by infrequent voiding and significant high post-void residuals (PVR). The detrusor muscle has reduced contractility, meaning it is unable to generate sufficient force to empty the bladder completely. This leads to urine accumulation in the bladder. Dysfunctional Voiding (DV): This is a crucial category where the primary problem lies in the poor relaxation of the external urethral sphincter during the voiding phase. Instead of the sphincter relaxing to allow urine to flow freely, it remains contracted or contracts inappropriately while the detrusor muscle attempts to empty the bladder. Voiding Postponement (VP): This refers to a behavioral pattern where children habitually delay or postpone urination, even when they feel the urge. Other Syndromes: The ICCS also acknowledges other specific presentations that may not fit neatly into the above categories but are considered functional bladder disorders. These include: Extraordinary Daytime Frequency: This refers to a pattern of extremely frequent daytime urination in children who have a normal bladder capacity and no evidence of overactivity or infection. The cause is often behavioral or related to changes in voiding patterns. Giggle Incontinence: This is a specific type of urge incontinence that is triggered by laughter. The sudden, forceful contraction of the abdominal muscles during laughter can provoke an involuntary detrusor contraction, leading to sudden urine leakage.