Voiding Dysfunction - Pediatric - Lecture Slides, Slides of Pediatrics

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Voiding Dysfunction in

Children

Perspective

 Incontinence is part of transitional phase from

infantile to adult lower urinary tract function

 Wetting disorders often considered necessary nuisance & tolerated until child lags behind peers  Parental concerns about voiding are common & often supersede the child's anxiety

 However, voiding dysfunction can be a sign of

underlying pathophysiology that needs Rx to

prevent Renal/Urologic damage

How the Lower

Urinary Tract Works

Bowl and Bladder Function

 Lower GU tract tied to lower GI tract  Same embryogenic origin: endodermal tissue  Up to sixth week gestation urogenital sinus & the hindgut empty into common cloaca

 Problems with elimination in one usually associated with problems in the other  Proper term is Elimination Dysfunction Syndrome

Lower Urinary Tract is a

Functionally Integrated Unit

Ureteral Vesicle Junction

Bladder

Sphincter

Urethra

Neurologic control

mechanisms

Anatomy & Neurophysiology of the

Lower Urinary Tract

Bladder (detrusor)

Stores urine at low pressure Compresses urine for voiding

Urethra

Conveys urine from bladder to outside world

Sphincter(s) internal & external

Controls urine flow & maintain continence between voidings

Nervous system control of Lower Tract

 CNS micturition centers  Exert voluntary control over spinal centers

 Spinal micturition centers  T10-L  Sympathetics via hypogastric Nerve  S2-S  Parasympathetic via Pelvic N  Somatic via Pudental N

CNS

micturition centers

T10- L

S2- S

Autonomic NS receptor Distribution

Voluntary Efficient Complete Low Pressure Voiding

Outlet relaxation:

CNS micturition Centers Inhibit sympathetic -adrenergic stimulation of bladder neck/posterior urethra & somatic stimulation of External Sphincter

Bladder Contraction:

CNS micturition Centers Inhibits -adrenergic bladder relaxation & stimulates Parasympathetic cholinergic stimulation of bladder fundus from S2-S4 via Pelvic Allows complete emptying Nerve at pressures < 40 mm Hg

CNS

micturition centers

T -L S2- S

Normal Voiding Study

Bladder Neck Pressures

Bladder Pressures

External Sphincter EMG Activity

Storage (cc) Voluntary Voiding docsity.com

Maturation of Voiding

Neonatal voiding

Controlled by sacral spinal cord reflex

 Bladder distention sends signals to sacral

spinal cord micturition center

Spinal cord micturition center sends efferent

signals that cause detrusor contraction &

relaxation of external sphincter

Results in frequent, complete, low pressure

emptying

Newborns void 20 x/day with only a slight

decrease during the 1st year of life

Maturation of Voiding

Bladder capacity increases & voiding

frequency decrease with growth  Bladder capacity in Ounces (30ml) = Age (yrs) +

 1-2 yrs: conscious sensation of bladder

fullness develops

 2-3 yrs: Ability to initiate or inhibit voiding

voluntarily develops

 2-4 yrs: Voiding comes under reliable voluntary

control

 By 4 years of age, most children have achieved an adult pattern of micturition

Maturation of Voiding

Initially child has better control over

external sphincter than bladder Easier to stop urination than start it Voiding inhibition done by contracting external sphincter rather than inhibiting bladder contraction

This pattern may be reinforced during toilet

training

Persistence of this pattern is bladder

sphincter dysnergia