Bed wetting is a phenomenon observed at extremes of age and can sometimes be a sign of a deeper problem. Passing urine in a normal bladder hinges upon an intricate network of connections between the central/ peripheral and autonomous nervous systems. This relationship results in the storage of urine in the bladder at low pressure while maintaining a high resistance in the urinary tract to prevent leakage and a corresponding release of this resistance with contraction of the bladder when voiding is needed.

In the pediatric population, up to 85% of 5 year old children are able to control their bladder (continent). Bed wetting in this population occurs when the child does not wake up to pass urine. This can be due to one or a combination of factors such as maturational delay, genetic factors, distrubed sleep, nocturnal polyuria or detrusor overactivity. There are several other features associated with each of these conditions that caregivers can look out for if they have a child suffering from bed wetting.

For example, maturational delay causing bed wetting is associated with language and speech delay as for genetics, if 1 parent had previously suffered from bed wetting as child, his/her child has a 50% chance of also wetting the bed, this increases to 75% if both parents suffered from bed wetting. In the case of nocturnal polyuria and detrusor overactivity, care must be taken to evaluate for more sinister underlying causes such as urinary tract malformations. Most bedwetting in the pediatric population does eventually resolve spontaneously. However, if the child is passing large amounts of urine at night or has frequent urinary tract infections, further investigations and a referral to a pediatric surgeon may be required.

In the older population, bed wetting due to urinary incontinence is generally associated with a loss of function of the mechanisms required to control the flow of urine out of the bladder. Stress incontinence is a common cause and is due to the anatomical structures in the pelvic floor that usually support urethral function becoming inadequate resulting in spontaneous “leakage” of urine.

Risk factors

Risk factors associated stress incontinence include age, spinal cord injury, previous prostate surgery for men and previous vaginal births in women. Unlike the pediatric population, stress incontinence does not go away by itself, therefore, management of the condition is focused on strengthening the pelvic floor through exercise such as Kegels exercises and getting the environment ready for any “leakages” with protective pads for beds and undergarments.

It is important not to dismiss all incontinence issues in the elderly as being from stress incontinence as there are issues such as prostate cancer in men or neurological diseases that can cause symptoms of bed wetting. Therefore a thorough history and examination by your doctor in order to rule out these other causes of incontinence.

Maintaining continence is a complex physiological process that when dysregulated can result in bed wetting. While some causes of bed wetting can resolve spontaneously particularly in the pediatric population, it is important to review every case with your doctor in order to eliminate any possibility of a more sinister cause behind the bed wetting.