Bladders and Bedwetting
Using the bathroom is an automatic, almost unconscious task; one we take for granted. But urination is actually a complicated process that involves the nerves, muscles, spinal cord and the brain. If everything is not functioning exactly as it is supposed to, problems like incontinence and bedwetting can result, making us realize what an important process it really is.
How the Urinary System Works
The urinary system is made up of two kidneys, two ureters, a bladder and a urethra. According to the National Association for Incontinence (NAFC), the kidneys remove waste products from the blood and continuously produce urine. The muscular, tube-like ureters move urine from the kidneys to the bladder, where it is stored until it flows out of the body through the tube-like urethra.
According to the National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC), the bladder is made of two types of muscles: the detrusor, which stores urine and squeezes to release urine; and the sphincter, a circular muscle at the bottom of the bladder which contracts to hold urine and relaxes when the detrusor contracts to pass urine into the urethra. The pelvic floor muscles, below the bladder, also help with continence by contracting to keep the urine in the bladder.
How Urinary Delays Affect Continence
When babies are born, their urinary systems are not fully developed. A baby's bladder fills to a set point, then automatically contracts and empties, according to the NKUDIC.
As a child grows, however, the urinary system develops, eventually allowing the bladder to send messages to the brain when it is full. The brain, in turn, sends messages to bladder, signaling it to not release until the child decides he's ready to use the bathroom.
Nighttime incontinence, or enuresis, is considered to be a problem once a child reaches age 5 or 6. From the ages of 5 to 10, according to the NKUDIC, the child's nervous system may not be fully developed to allow proper communication between the brain and bladder, rendering them unable to control when the bladder empties.
"Developmental delays either keep the brain from recognizing that the bladder is full or prevent the bladder's urinary sphincter ... from stopping urination during sleep," says Dr. Amy Pakula, a neurodevelopmental pediatrician and assistant professor of pediatrics at Emory University in Atlanta, Ga. "In some children, the arousal-control areas of the brain may also be affected, allowing the child to 'sleep through' a full bladder rather than waking up to urinate."
The body also normally produces an antidiuretic hormone at night, which reduces the amount of urine produced, according Dr. Pakula. "In some children who bedwet, the nighttime level of the antidiuretic hormone does not increase as expected," she says. "When this happens, the amount of urine produced remains the same as during the day, and the bladder continues to fill as much as it would during waking hours." If a child then does not sense the full bladder and does not wake up, he's sure to end up with a wet bed.
Children this age may also have smaller bladders, which are not able to hold as much urine. And in rare cases, according to the NKUDIC, bedwetting may be caused by physical problems in the urinary system, such as a blocked bladder or urethra, which can cause the bladder to overfill and leak, and nerve damage, which can cause constant dribbling. Your physician can rule out any physical problems.
When working on bedwetting, it can be helpful to use absorbent disposable underpants. When kids wake up dry, it can help their self-esteem and prevent the shame caused by wet beds. For parents, absorbent underpants mean less laundry in the morning.
No matter the cause of your child's bedwetting, always remember that it is out of his control. "The misconception about primary nocturnal enuresis is that there's something wrong with the kid, and there's not," says Dr. Frederick Kaskel, professor of pediatrics at Children's Hospital at Montefiore in the Bronx, N.Y. "They're normal. They just take a little longer to mature into this fully aware state so the brain can sense that they're getting full."