Nocturnal enuresis, the involuntary release of urine during sleep, is commonly known as bedwetting. While frequently associated with childhood, this issue can persist or develop suddenly in adulthood, affecting an estimated one to two percent of the adult population. It is a medical symptom that warrants investigation and is often treatable. Understanding the type and underlying causes of bedwetting is the first step toward finding an effective solution.
Classifying Bedwetting
Medically, nocturnal enuresis is divided into two categories based on a person’s history of dryness. Primary Nocturnal Enuresis (PNE) describes the situation where an individual has never achieved a consistent period of nighttime dryness. This means they have never been consistently dry for six months or more since childhood. PNE often relates to a developmental delay in the body’s natural regulatory mechanisms, such as hormone production or difficulty arousing from sleep.
The second classification is Secondary Nocturnal Enuresis (SNE), which occurs when bedwetting begins again after a person has been dry for at least six continuous months. SNE is much more likely to be a symptom of an underlying medical condition or an external factor that has recently changed within the body. Therefore, the onset of secondary enuresis typically requires a thorough medical evaluation.
Common Physiological Mechanisms
Three main physiological factors often work alone or together to cause bedwetting. The first is Nocturnal Polyuria, which is the overproduction of urine during sleeping hours. Normally, the body increases the production of Antidiuretic Hormone (ADH) at night to signal the kidneys to concentrate urine and decrease its volume. If there is insufficient ADH production or if the kidneys do not respond effectively, the bladder may fill faster than it can hold.
Another contributing factor relates to the bladder’s capacity and function, known as a Small Functional Bladder Capacity. This does not necessarily mean the bladder is physically smaller, but rather that the bladder muscles are overactive or irritable, triggering the urge to void at lower volumes. This involuntary contraction can cause the bladder to empty before it reaches its full holding potential.
The third mechanism involves Arousal Difficulty, which is the failure of the brain to wake up in response to a full bladder signal. As the bladder fills, it sends signals to the brain, which should prompt a person to wake up and use the toilet. If the sleep threshold is too high, they may not rouse to the signal, leading to involuntary voiding during sleep. This elevated arousal threshold can be compounded by certain medications or underlying sleep disorders.
Underlying Health Conditions
When bedwetting starts later in life, it is frequently a sign of an underlying health problem. Urinary Tract Infections (UTIs) are a common and treatable cause, as the infection irritates the bladder lining and increases the urgency and frequency of urination. Certain systemic diseases, such as poorly managed Diabetes Mellitus, can also cause bedwetting because high blood sugar levels lead to increased urine production.
Obstructive Sleep Apnea (OSA), characterized by repeated breathing pauses during sleep, is another frequent cause of SNE. The interrupted breathing and resulting low oxygen levels can trigger the release of a hormone that increases urine output, contributing to nocturnal polyuria. Chronic constipation can also put physical pressure on the bladder, leading to functional capacity issues.
Certain medications can induce or worsen bedwetting as a side effect. Drugs like sedatives deepen sleep and raise the arousal threshold, making it harder to wake up to the bladder’s signal. Additionally, some psychiatric medications, such as specific antipsychotics, can interfere with bladder muscle function or increase urine production.
Seeking Diagnosis and Management
Any adult who experiences new-onset bedwetting (SNE) or associated symptoms like pain, blood in the urine, or daytime incontinence should consult a healthcare provider promptly. The diagnostic process begins with a detailed medical history and a physical examination to rule out structural or neurological issues. A urinalysis and urine culture are performed to check for infection or signs of conditions like diabetes.
A healthcare professional may ask the patient to keep a bladder diary for a few days, which records fluid intake, timing and volume of voids, and episodes of wetting. This diary provides valuable data to determine if the issue is nocturnal polyuria, a small functional bladder capacity, or both. Understanding the pattern is the foundation for creating an effective treatment plan.
Management often begins with behavioral changes, such as restricting fluid intake for two to three hours before bedtime. Avoiding bladder irritants like caffeine and alcohol in the evening can decrease nighttime urine production and urgency. Enuresis alarms offer a conditioning therapy by sensing moisture and sounding an alarm to train the brain to wake up in response to bladder fullness.
Pharmacological Treatments
For cases where these measures are insufficient, a doctor may prescribe medications. The first is desmopressin, which mimics the natural ADH hormone to reduce night-time urine volume. Another element is anticholinergic drugs, which are used to calm an overactive bladder.