- Urinary incontinence is a common problem in children. At five years of age, 15 percent of children remain incompletely continent of urine. Most of these children have isolated nocturnal enuresis (monosymptomatic nocturnal enuresis)
- monosymptomatic nocturnal enuresis usually is divided into primary and secondary forms. Children who have never achieved a satisfactory period of nighttime dryness have primary enuresis. An estimated 80 percent of children with nocturnal enuresis have this form. The remaining 20 percent have had a period of dryness, usually for at least six months, before the onset of wetting begins; these children have secondary enuresis. Secondary enuresis often is ascribed to an unusually stressful event (eg, parental divorce, birth of a sibling) at a time of vulnerability in a child’s life. However, the exact cause of secondary enuresis remains unknown.
- Approximately 20 percent of children who have nighttime wetting also have significant daytime symptoms ]. The daytime symptoms may be limited to urgency and frequency, but often include incontinence (diurnal enuresis). Urologic and neurologic disorders (eg, detrusor instability, recurrent urinary tract infection, spinal dysraphism) are more common among children with diurnal symptoms than those with isolated nocturnal enuresis; approximately 15 percent also have troublesome encopresis
- . Patients who have nocturnal enuresis with daytime symptoms are described as having complex or complicated enuresis (also called dysfunctional voiding), whereas those who have associated urinary and bowel symptoms often are described as having dysfunctional elimination syndrome
- BLADDER MATURATION — Normal bladder function entails a complex interrelationship between autonomic and somatic nerves, which are integrated at various sites in the spinal cord, brain stem, midbrain, and higher cortical centers. The complex coordination permits urine storage at low pressure with high outlet resistance and voiding with low outlet resistance and sustained detrusor contraction.
- At birth, bladder function is thought to be coordinated through the lower spinal cord and/or primitive brain centers. Voiding at this stage is efficient but uncontrolled: uninhibited contraction is caused by progressive and sustained bladder filling. Voiding in the newborn also may be initiated by neurologically stimulating activities such as feeding, bathing, tickling, etc.
The newborn voids approximately 20 times per day. During the first three years of life, bladder capacity increases disproportionately relative to body surface area; by three years of age the number of voids per day decreases to approximately 11, while mean voided volume increases nearly fourfold. By four years of age, most children void five to six times per day
Development of bladder control appears to follow a progressive maturation whereby the child first becomes aware of bladder filling, subsequently develops the ability to suppress detrusor contractions voluntarily, and finally learns to coordinate sphincter and detrusor function. These skills usually are achieved, at least during the day, by approximately four years of age. Nighttime bladder control is achieved months to years after daytime control, but is not expected until five to seven years of age.
Incomplete development of bladder control results in more complex wetting problems that are almost always associated with diurnal enuresis. These include the uninhibited bladder of childhood, bladder sphincter dyssynergy, recurrent urinary tract infections, and some cases of vesicoureteral reflux
- CAUSES — Monosymptomatic nocturnal enuresis may result from one of several possible abnormalities; in any given child, several of these factors may occur simultaneously . The following factors are believed to contribute to nocturnal enuresis:
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- Maturational delay
- Genetics
- Functional small bladder capacity
- Abnormal diurnal secretion of vasopressin ( antidiuretic hormone, ADH)
- Nocturnal polyuria
- Detrusor instability
- Sleep disorders
- Psychological issues
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- EVALUATION — The evaluation of the child with monosymptomatic nocturnal enuresis includes a careful history, physical examination, and urinalysis.
- History — Important issues to be considered in the history include
- Presence of daytime wetting or symptoms
- Any prolonged period of dryness
- Family history of nocturnal enuresis
- Frequency and trend of nocturnal enuresis (eg, number of wet nights per week or month, number of episodes per night, time of episodes, approximate volume of each episode)
- Fluid intake diary
- Voiding diary (eg, number of daytime voids, usual volume of voided urine [to estimate bladder capacity], maximum length of time between voids, difficulty starting or stopping stream, dribbling, sensation of incomplete emptying)
- Stooling diary (to determine whether there is associated constipation or encopresis), an important cause of secondary enuresis
- Medical history (eg, sleep apnea, diabetes, sickle cell disease or trait, urinary tract infection, gait or neurologic abnormalities)
- Social history (particularly important in secondary enuresis)
- Assessment of how the problem has affected the child and family
- Determination of which interventions the family has tried
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- Physical examination — The physical examination of the child with primary monosymptomatic nocturnal enuresis usually is normal. Aspects of the physical examination that may indicate an underlying medical etiology for enuresis include:
- Detection of wetness in the undergarments is a sign of diurnal enuresis.
- Palpation of stool in the abdomen suggests constipation or encopresis.
- Perianal excoriation or vulvovaginitis may indicate pinworm infection
- Poor growth and/or hypertension may indicate renal disease.
- Presence of abnormalities of the lower lumbosacral spine (eg, abnormal tuft of hair or an abnormality in the gluteal fold) and/or abnormalities on neurologic examination of the perineum and lower extremities may indicate occult spinal cord abnormalities.
- Detection of incomplete bladder emptying by percussion and/or palpation, slow urinary stream, dribbling, or intermittent stream may indicate urologic abnormalities (eg, posterior urethral valves, ectopic ureter). Undescended testicles, underdeveloped scrotum, and abnormal location or characteristics of the urethral meatus also may indicate urologic abnormalities.
- Urinalysis — The urinalysis (including specific gravity) is obtained as a screen for diabetic ketoacidosis, diabetes insipidus, water intoxication, and/or occult urinary tract infection. Urine culture is not necessary unless indicated by the presence of white blood cells or nitrites on urinalysis. (See appropriate topic reviews).
- Imaging — Urologic imaging (renal sonogram and voiding cystourethrogram) is reserved for children who have significant daytime complaints, a history of urinary tract infection(s) not previously evaluated, and/or signs and symptoms of structural urologic abnormalities .
Neurologic imaging (usually an MRI of the spine) is indicated in children who are noted to have abnormalities of the lower lumbosacral spine on neurologic examination of the perineum and lower extremities
Dr. Jayaprakash
Superintendent, ICH.
Institute of Child Health.
Gov. Medical College Kottayam.
Kerala, India.