How continence is acquired and maintained
To date we have studied structure and function of the bladder, urethra and pelvic floor, now we are going to look at how this works and how we learn to control our bladder, to be ‘continent’.
None of us are born continent. Continence is a skill that is acquired by most, but some individuals need extra support to achieve it, some may never fully achieve it, and some maintain continence only with difficulty.
In babies the development of the central nervous system is incomplete. At birth the bladder function is not fully matured, as the parasympathetic nerves are not fully inhibited while the bladder is filling. Therefore, bladder contraction may happen during filling. Furthermore, detrusor contraction and sphincter relaxation are not fully coordinated during voiding, so the bladder may not fully empty. Consequently young babies may have interrupted voiding, which is passing urine two or three times within ten minutes. They may not fully empty their bladder with every void.
Infants normally pass urine when they are awake. However, if they do void when they are asleep their sleep pattern changes, usually from quiet sleep to active REM sleep, or to movement of their limbs or faces, or to a change in heart and breathing rate. As arousal is detectable in over 90% of term babies during voiding, it is considered that there is cortical arousal when the bladder empties.
Babies have higher bladder pressures than older children and adults. This is partially because they have smaller bladders and narrow urethras. The higher pressure is more marked in boys who have a longer urethra than girls. Higher pressures may also be as a result of the discoordination between the sphincter and the detrusor.
Newborn babies may have a bladder capacity as small as 10mls. This gradually increases until adult capacity is reached, typically at about 14 years of age. Interrupted voiding gradually reduces as the baby ages and is usually gone by one year of age. Post void residuals also reduce as the baby matures, as do bladder pressures.
There is some evidence that toilet training can promote bladder maturation. Commencement of toilet training is generally happening later in most affluent countries than in previous generations. However, prior to the 1960s in the United Kingdom children were usually toilet trained in the second year of life. This is still the case in many more traditional societies, with children in some cultures achieving at least a degree of bladder control by nine months of age.
Development of sphincter competence normally follows a set pattern:
Control of bowel during sleep - usually achieved by the age of one year
Control of bowel when awake
Control of bladder when awake
Control of bladder when asleep
Some children may achieve control of their bladder when awake prior to that of their bowels.
Clinical practice points about bladder control.
An understanding of this is important when assessing patients with dementia. With dementia there may be a gradual loss of skills that affect continence.
Did you know? What we learn first we lose last, so we tend to lose urinary control first and then bowel control.
Therefore if a person with dementia has problems with bowel control but has bladder control, the bowel problem is probably not caused by their dementia and may have another cause.
Did you know? Continence is a skill we acquire, we have to use it or we will lose it.
Did you know? If you are a bedwetter as a young person you are more likely to have an overactive bladder and nocturia as an adult[2-4].
Many children now go to school at the age of 4-5 and are not continent.
Why do think this is more common now than previously? Make notes of your thoughts and join the conversation to compare your thoughts with others.
1. Van der Cruyssen K et al (2015) The voiding pattern in healthy pre- and term infants and toddlers: a literature review Eur J Pediatr 174 1129-1142
2. D’Ancona CAL, Baena de Moraes Lopes MH, Faleiros‐Martins AC, Correia Lúcio A, Martins Campos R, Vilton Costa J. Childhood enuresis is a risk factor for bladder dysfunction in adult life?. Neurourol Urodyn 2012;31:634–6. [Cited 3 August 2018] Available from: https://doi.org/10.1002/nau.21195
3. Akashi S, Tomita K. The impact of a history of childhood nocturnal enuresis on adult nocturia and urgency. Acta Paediatr 2014;103: e410–15. [Cited 3 August 2018] Available from: https://doi.org/10.1111/apa.12694
4. Goessaert A-S, Schoenaers B, Opdenakker O, Hoebeke P, Everaert K, Vande Walle J. Long-term followup of children with nocturnal enuresis: increased frequency of nocturia in adulthood. J Urol 2014;191:1866–70. [Cited 3 August 2018] Available from: https://doi.org/10.1016/j.juro.2013.12.051
5. Sillen U (2004) Bladder Function in Infants Urodynamics reveal high pressures and immature coordination. Scand J Urol Nephrol Suppl 215 69-74
6. Guerra L et al (2014) Best practice in the assessment of bladder function in infants. Ther Adv Urol 6 4 148-164
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