These changes are attributed to decreased urethral vascularization, to a decrease in alpha-adrenergic receptors and to smooth muscle tissue atrophy.
The aim of initial investigations therefore is to identify the group of infants at greatest risk - principally boys with urethral valves or severe primary reflux.
Because of the morbidity and cost of invasive surgery, there have also been attempts to increase urethral resistance by more conservative measures.
This would lead to decreased urethral closure pressure, predisposing the patient to the appearance of stress incontinence.
There is general consensus that maximum urethral pressure, maximum urethral closure and length of the functional urethra decrease with age in women.
The lower urethral pressure may not compensate for the rise in intravesical pressure in pregnancy.
Urethral pressure is maintained at a higher rate during filling, by contraction of muscle fibres within the bladder neck and urethra.
If faecal loading and urethral obstruction due to prostatic hypertrophy have been excluded, then use of intermittent catheterization should be considered.
