(1) Maturational delay is a commonly accepted but unproven cause of nocturnal incontinence. This refers to the enuretic child’s inability to send, perceive, or respond to information about a filled bladder during the night. Support for this theory comes from the spontaneous cure rate and relationship between enuresis and maturation of motor systems.

(2) Sleep and arousal factors. Originally, it was thought that enuresis was a nonrapid eye movement dyssomnia (like sleepwalking and night terrors). Data suggest that enuresis occurs in all stages of sleep and that there is no difference in sleep patterns between children with enuresis and their nonenuretic peers. Obstructive sleep apnea (OSA) can be associated with nocturnal enuresis. In some cases, interventions for OSA including a tonsillectomy and adenoidectomy can result in resolution of enuresis symptoms.

(3) Central nervous system factors. Continuing research has focused on the possible role of antidiuretic hormone secretion in children with nocturnal enuresis, leading to an increase in urinary output and suggests that this may be a contributing feature in enuresis. Although desmopressin acetate (DDAVP) is a recognized and approved treatment for enuresis, considerable data have accumulated that make this etiology less likely.

(4) Psychopathology/stress. There are no data to support enuresis as a neurotic disorder. Similarly, although stress may exacerbate or contribute to enuresis, it is not a primary etiologic factor. However, certain conditions, such as attentiondeficit/hyperactivity disorder (ADHD) are related to an increase in enuresis. However, the ADHD itself may not be causal but representative of a neurochemical marker.

(1) Increased bladder irritability. A common cause of secondary enuresis is increased bladder irritability, usually due to a urinary tract infection. In addition, any mass impinging on the bladder (e.g., severe constipation) can increase bladder irritability.

(2) Increased urinary output. Any process that increases urinary output can cause enuresis (e.g., diabetes mellitus, diabetes insipidus, and sickle cell disease).

(3) Bladder capacity. Bladder capacity tends to be decreased in children with enuresis compared with their nonenuretic siblings. This reflects differences in functional, rather than absolute, bladder capacity, with contractions occurring earlier in filling.

(2) Micturation deferral. A common cause of daytime wetting in preschool children is due to holding of the urine and ignoring the urge to void, usually during play. Incontinence results when detrusor contraction cannot be suppressed. Children with short attention spans often fail to respond to body signals until it is too late. This type of wetting can be more common in children with behavioral issues.

(3) Abnormal sphincter control. Although abnormal urinary sphincter control is rare, insidious pathology (e.g., spinal cord abnormalities) can cause abnormal sphincter control. Some hypothesize that there is a group of children with decreased sphincter strength without obvious cause who may have a higher incidence of diurnal enuresis.

(4) Structural abnormalities. Girls with ectopic ureters, which empty into the vagina, have constant wetting with no recognized episodes of incontinence. Partial labial fusion may develop after inflammation, allowing urine to collect in a pocket behind the fused labia minora and subsequently leak.

(5) Vaginal reflux. Overweight girls or girls who sit with their legs together when urinating, can reflux urine into the vagina. The urine will then leak out over the next several hours without the urge to void. This causes almost constant daytime wetting without nighttime episodes.

(1) Urge syndrome. Children with daytime and nighttime wetting, as well as urgency and frequency, often have unstable detrusor contractions early in bladder filling. They often squat, sitting asymmetrically on one heel in an effort to prevent a detrusor contraction. Symptoms resolve with time, usually by 10-12 years.

(2) Giggle incontinence. Emptying the bladder entirely while laughing may be familial. It is common in school-aged girls and generally resolves with maturity.

(3) Stress incontinence. With increased abdominal pressure, such as during coughing, some children’s bladders empty.

(4) Postvoid dribble syndrome. Children may sense wetness after a void but without actual incontinence.