Some children have always wet the bed at night while others start to wet after being dry for a variable period of time. Secondary nocturnal enuresis (SNE) is bedwetting that develops after at least six months of consistent dryness and accounts for about one quarter of children with bedwetting. By age ten years, up to 8% of children will develop SNE. The number of children with SNE, as a percent of all cases of nocturnal enuresis, increases with age.
The emotional impact of SNE on a child and family can be significant. Numerous studies report feelings of embarrassment and anxiety, loss of self-esteem, and adverse effects on self-perception, interpersonal relationships, quality of life, and school performance. In children with SNE the possible causes are similar to those found in children who always wet, and include a problem with waking-up (arousal) to the sensation of a full or contracting bladder, making too much urine at night, or a bladder that acts small at night. A problem with arousal is likely the most important. A family history of bedwetting is found in about 50% of children with SNE.
Unlike the children who have always wet, psychological stress is a potential cause of SNE. The later the onset of the wetting, the more likely the cause is due to psychological stress. Many common situations can be stressful, such as birth of a new sibling, parental divorce or separation, death in the family, child abuse, or problems at school.
A common cause of SNE in the pre-school child is an overactive bladder (OAB). Children with OAB pee more than usual, often have to run to the bathroom, and wet by day. Bladder infection is another cause of SNE; about 15-20% of children with cystitis present with nighttime wetting. Constipation also can be a cause or an aggravating factor. Obstructive sleep apnea (OSA) is an uncommon cause of SNE. Large adenoids are the most common cause of OSA that leads to SNE.
Given the above, a careful history and a complete physical examination are important. A urinalysis is the only essential diagnostic test. X-rays are usually not needed.
Children with SNE will benefit from a caring and patient attitude by their parents. There is no role for punishment and a positive approach is important to instill confidence and enhance compliance. Motivation is an important factor for success. Many of these children have "given up" on the concept of dryness and an optimistic attitude should be encouraged. Concentrating on normal voiding by day, not overdoing fluids in the hours before bed, and taking your child to the bathroom before bedtime and later before you turn in, can help with the wetting. Moisture alarm therapy and medications are available, and your doctor can help you decide which approach is best.