- The most common cause in children >5Y is detrusor instability.
- Common reversible causes: UTI, constipation, emotional stress.
- Diagnosis requires a full voiding and bowel history with examination to exclude neurological disorders.
- Treatment with oxybutynin, fluid restriction, bladder training and behavioural therapies may be effective.
Bed-wetting – enuresis
This is where a patient wets the bed after the age at which you would expect them not to.
At first, all children will wet the bed at night. This is normal, and occurs when the child has not yet learned to manually control their sphincter. Girls usually manage to achieve this before boys; most girls stay dry by about age6, while in boys it is age 7. By age 10, 95% of children stay dry at night.
Bed wetting depends on two things:
Vasopressin (ADH) – normal cyclical patterns of this hormones secretion mean that higher levels are secreted at night, and so there is less urine produced at night. When you are born, the cyclical secretion of this has not yet developed- and in some people it does not develop properly (perhaps less than 10% of enuresis patients – and hereditary factors may be involved). You can take a nasal spray of this hormone before bed to prevent bed wetting – however prolonged use of this is not recommended.
Ability to recognise when bladder is full- this is another mechanism that develops as the child grows, and it is independent of the vasopressin mechanism.
At age 5, 20% of children will bed wet.
At age 10, 5%
At age 15, 2%
Even after the age of 18, up to 1% of people will wet the bed.
There are two main types of enuresis:
- Primary nocturnal enuresis (PNE)– this is where the child has never experienced a period of prolonged dryness and continues to wet the bed more than 2 nights a week after the age at which they would be expected to have outgrown the phenomenon.
- Secondary nocturnal enuresis(SNE) – this occurs after the child has had a period of at least 6 months without bed wetting. It can be related to emotional stress and bladder infection.
As well as the causes discussed above, up to 10% of children who bed wet may have a defect of the urinary tract that causes their problems.
- Waiting! – many parents get anxious when their child wets the bed, but often they will outgrow it if you give them long enough. Some research shows that punishing a child for bed wetting can make the situation worse, as the punishments results in lower self-esteem and a downward spiral of symptoms.
- ADH spray
- Alarm – the child wears an alarm at night time that is attached to their pants, and goes off when they get wet. This wakes up the child, and helps them to associate the feeling of a full bladder, with having to wake up. These alarms make children 13x more likely to stop bed wetting, however there is a high relapse rate (up to 50%) and treatment regimens often have to be repeated.
- Most commonly due to constipation in children with psychological predisposing factors.
- History and examination is required to rule out physical cause e.g. celiac disease and Hirschsprung’s disease.
- Management involves explaining the physiology of the condition (remove blame from child); treatment of constipation (stimulant laxative); behavioural strategies (toilet-sitting times).
- 5 year cure is 75%