Author: Dr Marie Carmella Lapitan
Nocturnal enuresis, commonly known as bedwetting, is the involuntary discharge of urine during sleep by a child old enough to be expected to have full bladder control. A child is labelled as enuretic if the wetting is regular, occurring at least three times per week, and persists beyond the age of five years for girls and six years for boys.
Bedwetting is a common problem. Worldwide figures show that up to 15% of children less than 5 years of age suffer from nocturnal enuresis. This decreases to 10% by age 7 years, 4-5% by 10 years and 1-2% by 18 years. According the Dr Chao, although the true incidence of enuresis in Singapore is unknown, the overall prevalence is believed to be around 10%. Majority of the patients who consulted and are diagnosed to have nocturnal enuresis are in the age range of 7 to 12 years old.
How does enuresis develop?
What is the pathophysiology of the disease?
Prof K Hjalmas presented a simple explanation of the development of enuresis in a child. He proposed that the central event in enuresis is the early occurrence of a full bladder during sleep. This is brought about by an increase in the production of urine or a relatively decreased bladder capacity. The determining factor in enuresis is the ability of the child to wake up when the bladder is filled up. If the child does not wake up when the bladder beings to empty itself, enuresis ensues.
What causes enuresis?
The exact cause of enuresis is still unknown. In contrast to the obvious symptoms of bedwetting, its nature and causes remain unclear. However, it is important to have an understanding of the facts associated with bedwetting because they form the basis for treatment.
The most accepted theory is that nocturnal enuresis represents a maturation or developmental delay in attaining bladder control. This explains the reason why even without treatment and intervention, 10-15% of bedwetters attains dryness each year. Everyone is a born bedwetter. As one grows older, the brain continually develops so that by the age 5-6 years, full control of the bladder is attained in the majority. However, in some, this process takes a longer time, hence enuresis.
Recently, more evidence has been gathered showing bedwetters as having decreased secretion of anti-diuretic hormone at night. ADH or vasopressin acts on the kidneys to reduce the amount of urine produced during sleep, allowing the bladder to hold urine.
Many bedwetters do not produce the normal high levels of ADH at night and therefore their bladders fill up faster, resulting in the need to empty in mid-sleep.
Sleep disorders have also been associated with nocturnal enuresis. Deep sleep patterns have been found among bedwetters. As emphasised by Prof K Hjalmas in his discussion on the pathophysiology of the condition, it is the inability of the patient to wake up to empty accidents in the bed during the night.
Recent studies have identified a gene for enuresis on chromosome 13q. Thus, the hereditary factor is very much implicated in causing bedwetting. If one parent is affected, there is almost one in two chance of the child being enuretic. If both parents are affected, the risk increases to 75%. Enuresis is 2-3 times more common among males than females.
All of the lecturers agreed that psychological problems do not cause enuresis in the majority of cases. In fact it is the bedwetting that brings about these problems in the child. The only situation where emotional stress leads to bedwetting is in the case of secondary enuresis where bedwetting recurs in a child after prolonged period of dryness. Secondary enuresis is usually transient and resolves with the alleviation of the stressor.
There is not basis showing that an underlying disease causes primary nocturnal enuresis. Most the patients are healthy and have no other medical problems. Improper toilet training has also been discounted as a significant factor in causing enuresis.
How does one approach the problem of enuresis?
The first and foremost step in managing bedwetting is to establish the correct diagnosis. Second, one must exclude other treatable diseases that present as enuresis such as urinary tract infection. The need for active treatment is then assessed. At all times parents and the child are reassured and support is given. Finally, the physician should be able to offer various treatments option if the need for intervention is deemed necessary.
How is nocturnal enuresis diagnosed?
In the approach to the diagnosis of nocturnal enuresis, it is important to rule the other problems associated with bedwetting, such as urinary tract infection and anatomic genitourinary tract disorders. The physician should take a complete medical history and physical examination. Particular attention should be given to the presence of a palpable bladder, or kidney, signs of neurologic diseases such as muscle atrophy, spine abnormalities and altered perineal sensation. Watching the child voiding is also very helpful.
The laboratory investigation for enuresis is limited to a urinalysis and a urine culture. Other procedures, such as renal ultrasound or other imaging studies and urodynamics are performed only in the presence of unusual features of symptoms accompanying enuresis.
Why is there a need to treat bedwetting?
Nocturnal enuresis is usually benign and self-limiting. Even without treatment, many bedwetters eventually become dry. However, the problem must not be dismissed and ignored because it affects the psychosocial development of the sufferer. The child develops a low self-esteem and adjusts poorly in society. Bedwetting also causes intolerance, resentment and rejection from parents and siblings. Moreover, it is a source of embarrassment and social stigma. Therefore, the problem of nocturnal neuresis should always be addressed.
How is nocturnal enuresis treated?
When should bedwetting be actively treated?
The decision to actively treat enuresis is individualised, depending on the age, severity of wetting and the psychosocial impact the condition has on the patient and family. Dr Chao recommends active intervention in cases where the child has reached 7 years of age and wets 3 or more nights per week. Treatment of the younger child with less frequent episodes of bedwetting may be done if the problem burdens the sufferer or the family to a significant extent.
There are different treatment options that may be used to treat nocturnal enuresis.
Desmopressin, a synthetic form of the anti-diuretic hormone, is the foremost drug in the pharmacologic treatment of nocturnal enuresis. It works by limiting the production of urine at night. It is available as a nasal spray, given at a dose of 20-40 mg per day or one to two sprays per nostril at night. In Singapore, where the incidence of allergic rhinitis in children is deemed high, making the spray ineffective, Dr Yap presented a study showing that the oral form of desmopressin is as effective in treating enuresis. The tablet form is given at a dose of 200-400mg at night.
At trial of two to four weeks of the drug is given to assess the patient’s response. The target is a reduction of wet nights to at least 50%. In cases of response, treatment is usually long term, lasting from at least three, usually six months. Once dryness is achieved, the dose of desmopressin is slowly lowered and eventually discontinued. Dr Yap showed that 67% of bedwetters treated with desmopressin in Singapore became dry.
Desmopressin is safe. Side effects were rare and include headaches, abdominal cramps and poor appetite. The main concern with the use of desmopressin is the occurrence of water retention, which if unattended and severe, may cause fits and convulsions. Therefore, emphasis is given to avoiding fluids one to two hours prior to bedtime for all those taking the drug.
The drug is available from majority of pharmacies and all hospitals upon the prescription by a doctor.
Tricyclic antidepressants, most commonly used being imipramine, was once the drug of choice for enuresis. They act by relaxing the bladder and by lightening sleep. Nowadays, however, it is used only on special indications because of the very high risk of drug overdose and intoxication. Imipramine is given at a dose of 1-2 mg/kg, usually as a 25 mg tablet taken before sleeping.
Anticholinergics such as oxybutynin or Ditropan, may be used for enuresis in cases where there is a very prominent symptom of urgency and bladder overactive.
The use of the enuretic alarm is the most effective method in treating bedwetting, especially in producing a long-term result. It consists of a wetness sensitive pad placed onto the child’s underwear connected to an alarm system. When the child urinates and the pad is wet, the alarm sounds off, waking up the child and ceasing urination. The pad is then disconnected from the alarm and the child completes voiding in the toilet. With time, the child will be conditioned to awaken when the bladder is full, before leakage occurs.
The effectiveness of the enuretic alarm depends highly on the motivation of the child and the parents. Thus, it is most ideally used on a relatively older child who is well motivated and with supportive parents. It has the highest response rate of up to 80% among all the treatment regimens for nocturnal enuresis.
One of the recent advances in the management of nocturnal enuresis is the concept of bladder pre-treatment. This behavioural modification method involves placing the child in a timed voiding schedule, training him to start urination at will every two hours. The child is motivated to “be the master of the bladder”. Such regimen, when started two weeks prior to giving desmopressin, was found to increase the response rate to the drug.
How to cope with bedwetting?
Dr Ng provided three simples guidelines for parents to follow in dealing with their enuretic child. The first step is to understand bedwetting and its treatment. The child must be brought to a doctor for the proper assessment. It should be realized that enuresis is common and that it is not intentional and not due to laziness. Enuresis should not be mixed up with other behavioural problems.
Secondly, parents must be able to empathize with their bedwetting child. They must learn to put themselves in their child’s shoes and understand his feelings. Lines of communication must be kept open. Parents must understand the child’s shame, feeling of low self-esteem and fear of being found out. Parents should not scold, blame, tease or punish the child. They should always stand by the sufferer and educated the siblings about the problem.
Lastly, the family, especially the parents of the bedwetter should learn to turn adversity into strength. Parents must become good role models in making the problem of bedwetting into an opportunity to teach the affected child on problem solving and the rest of the family about respect for oneself and others.