Physiology of Normal Urination
The process of urination is very complex. Urination involves the coordination of two different systems, the bladder (involuntary control) and the sphincter (voluntary control). The bladder muscle relaxes as it fills to allow storage of urine. When the bladder has almost reached capacity, a signal is sent to evacuate the bladder. During the time of bladder filling the sphincter muscle is in a state of tonic contraction, holding the urine back. It is not until the sphincter is relaxed that the bladder contracts to empty.
Abnormal Voiding and Voiding Dysfunction
During normal development children become more aware of their bladders. This maturation process allows the ability to control their bladder and prevent wetting. Children learn to override the normal tendency of the sphincter to relax by contracting their sphincters, thus staying dry. This is a normal reaction of a child to prevent wetting and allows a child time to get to a bathroom. However, an unhealthy situation occurs when a child continues to maintain a contracted sphincter against a full, or straining bladder. This, in essence, sets up two muscles working against each other. Over time, muscle hypertrophy will occur, and the bladder wall will become two to three times its normal thickness because of muscle fiber enlargement. In severe cases damage to the upper urinary tracts can occur.
Timed Voiding Instructions
Children with voiding dysfunction need to establish a timed voiding schedule. This means that the bladder should be emptied before the urge to go to the bathroom. Every two hours during the day is a good place to begin. The goal of a voiding schedule is to break old habits and learn healthy ones. The new habits allow control and consistent emptying of the bladder. Watches and alarms are given to the children in the clinic to establish independence during this regimen. Patients keep voiding diaries to record their progress. Letters are written for schools to ensure compliance during classroom hours. Hints are also given to children to learn how to relax their pelvic floor during urination.
In addition to establishing a voiding schedule, every child with diurnal enuresis needs to have a daily bowel movement. Suggested treatments include using stimulants for short-term use (4-8 weeks). Stimulants include Chocolate Ex-Lax 1-2 squares, Senokot Children’s Syrup 1-2 tsp. or Dulcolax 1 tablet. All stimulants should be given at bedtime. Children should also be encouraged to sit on the toilet for 5 minutes following meals. Following the use of a stimulant the patient should begin a stool softener and add fiber in the diet. Softeners are safe for long-term use and include Milk of Magnesium 1cc/kg/dose or Mineral Oil 1cc/kg/dose. If mineral oil is used greater than 2 months, vitamins should be supplemented due to malabsorption of fat-soluble vitamins.
Incentive programs are a useful method to promote compliance with the bowel and bladder program prescribed for patients in the Dry Time Clinic. Reward systems are discussed and established for patients and their parents. In addition, prizes are given in clinic if patients show compliance by bringing their voiding diaries to follow up appointments.