"Enuresis" is an inability to control the flow of urine, and "nocturnal" means that this happens at night. The usual definition of nocturnal enuresis is bedwetting over the age of five years.
It's common for toddlers to wet the bed, as they have not yet learned to control the flow of urine effectively. However, bedwetting can be a problem for older children too.
A child may wet the bed one or more times per night, and may sometimes have problems staying dry during the day, too. Betwetting occurs on most nights in 15% of five year olds and is still a problem for up to 3% of 15 year olds. It's not an illness, but a condition that can be treated effectively and permanently.
There are two types of nocturnal enuresis. Primary nocturnal enuresis is when a child has never developed complete night-time bladder control. Secondary nocturnal enuresis is when a child has accidental wetting after having had bladder control for six or more months. It's often associated with a period of emotional stress such as the birth of a younger sibling, a bereavement or school worries.

The urinary system
Urine is stored in the bladder, which stretches like a balloon as it fills up. When it stretches to a certain point, the nerves in the bladder wall send a message to the brain saying that it needs to be emptied. Urine passes out through the urethra. If a child is asleep and the brain does not "hear" this message, the bladder empties anyway.
The cause of bedwetting is unknown, but some factors are linked to it.
Parents worried about bedwetting can consult their GP, health visitor or school nurse. Most children will only need a general physical examination, and will have their urine tested with dip sticks.
It is rare that a child who wets the bed has any underlying illness. However, other possible problems such as diabetes, infections, or abnormalities will need to be ruled out.
Treatment is not usually needed for children under six, because in most children, it will resolve spontaneously.
Treatment options include:
A child who wets the bed needs to develop a better response to a full bladder, and an enuresis alarm can be an effective way to do this. When the child starts to wet the bed, a moisture sensor sends a signal to a control panel, which sounds an alarm. Some alarms also vibrate, which is useful for children with hearing impairments or those who sleep in a room with others.
As well as waking the child, who gets up to go to the toilet, the alarm stimulates the child's pelvic floor muscles to contract and so control the flow of urine. Gradually the child is conditioned to wake before the alarm sounds - or to sleep through the night without needing to urinate - and should start to achieve dry nights.
It is not usually recommended that children start using alarms till they are six or seven. They need to be old enough to understand the problem and how they have a part to play in treating themselves.
Alarms are effective in about 70% of children, but in 10-15% bedwetting returns. Continuing to use the alarm for at least three weeks after the child's last wet night can reduce the chance of this happening. A child will usually need an alarm for between three and five months.
Alarms may be bought or hired from the local community health/child guidance service - a specialist incontinence nurse may be available to give advice.
Medications can work more quickly than alarms to treat bedwetting, so may be useful to help a child to build up confidence, especially if he or she is going on a school trip or sleepover. However, medication only manages the problem in the short term rather than curing it.
A desmopressin nasal spray is usually effective in the short term. It works by making the child produce less urine. It works quickly and produces few side-effects. One puff is given to each nostril before bed. Desmopressin tablets are also available.
A drug called imipramine, which is used as an antidepressant in adults, may help by improving the child's sleep patterns or affecting the way the bladder muscles of the bladder work. However, it should not be used for more than three months. There may be side-effects such as changes in behaviour. It can be fatal in overdose and must be stored out of children's reach.
Some children who have daytime wetting as well may be diagnosed as having an "overactive bladder". This results in the bladder contracting even though it’s not full. A drug called oxybutynin may be helpful for this particular type of enuresis.
It is possible to use drugs and an alarm at the same time. Scientific evidence suggests that more children become dry after using the alarm with drugs, compared to the alarm alone.
There is some scientific evidence to suggest that ultrasound treatment and electro-acupuncture may help, but these need more investigation.
It's best to talk openly to your child about the problem. Give reassurance that he or she is not ill and that this problem can be solved. Praise all signs of improvement and all your child's efforts to conquer the problem. Do not blame, criticise or punish your child or call them dirty or babyish.
Tips for a dry night
There are a number of specialist products available to keep beds dry, such as plastic mattress covers and dry-pants (mini-nappies). An enuresis nurse can offer advice, as can the organisations below.
Education and Resources for Improving Childhood Continence (ERIC)
0845 370 8008
www.eric.org.uk
The Continence Foundation
0845 345 0165
www.continence-foundation.org.uk
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