152 Chapter 18
Nocturnal enuresis
Primary and secondary
Children and adolescents are said to have primary enuresis when they
have never acquired normal bladder control. By contrast, someone who
acquires bladder control for at least six months and then loses it again is
said to have secondary enuresis. This sort of relapse is most likely at the age
of 5 or 6 and is rare after the age of 11. Primary and secondary enuresis are
equally likely to be associated with a positive family history, but do differ
in other ways: secondary enuresis has a worse prognosis and is probably
associated with a higher likelihood of psychiatric disorder.
Prevalence
Table 18.1 shows the prevalence of nocturnal enuresis occurring at least
once a week in the Isle of Wight study. The current DSM-IV threshold for
nocturnal enuresis is set higher – at twice a week or more – resulting in
a lower prevalence, for example, 2.6% at 7 in the English ALSPAC study
(1.6% in girls, 3.6% in boys). The emergence of a male preponderance
reflects two processes:
1 Males are slower to achieve dryness (that is, slower resolution of
primary enuresis).
2 Males are more likely to relapse (that is, more liable to secondary
enuresis).
After the age of 7, secondary nocturnal enuresis is commoner than
primary nocturnal enuresis.
Risk factors
Around 70% of affected children have afamily historyof enuresis in at least
one first degree relative. The likelihood of having a family history is the
same for primary and secondary enuresis, and for those with and without
associated psychiatric problems. Linkage studies have been carried out on
multi-generation families where many family members have nocturnal
Table 18.1Prevalence of nocturnal enuresis occurring once a
week or more often
Age Prevalence (%) Male:female ratio
513 1:1
7 5 1.4:1
9 2.5 1.6:1
14 0.8 1.8:1
Source:(Rutteret al., 1970).