Atonic bladder is a condition where the bladder’s detrusor muscle loses its ability to contract. This prevents the bladder from emptying properly. In a healthy system, the bladder wall stretches as it fills with urine, which sends nerve signals that give you the urge to urinate. The brain then signals the detrusor muscle to contract and the urethral sphincter to relax, allowing for voluntary urination.
Underlying Causes of Atonic Bladder
The primary driver of an atonic bladder is damage to the nerves that control its function. Neurological conditions are a frequent source of this nerve interruption. For instance, diabetes can lead to diabetic cystopathy, a complication where nerve damage impairs the sensation of a full bladder and reduces muscle contractility. Similarly, conditions like multiple sclerosis, stroke, and spinal cord injuries can disrupt the communication pathways between the brain, spinal cord, and bladder.
Surgical procedures within the pelvis can also inadvertently lead to an atonic bladder. Operations such as hysterectomies or extensive surgeries for cancer can sometimes damage the delicate nerves responsible for bladder control.
Another cause is the long-term overstretching of the bladder muscle itself. This can happen due to a chronic obstruction that blocks the flow of urine, such as an enlarged prostate in men or a urethral stricture. Over time, the constant strain of trying to push urine past the blockage can weaken the detrusor muscle.
Recognizing the Symptoms
The most direct symptom of an atonic bladder is urinary retention, which is the inability to empty the bladder completely, or at all. Sufferers may feel the need to urinate but are unable to do so. This can leave a person with a persistent and uncomfortable sensation of fullness, even right after an attempt to use the restroom.
This retention often leads to a condition called overflow incontinence. This is not incontinence from a bladder spasm, but rather an unintentional leakage of urine that occurs when the bladder becomes so full that it simply overflows. The urine may dribble out involuntarily because the pressure inside the overfilled bladder exceeds the ability of the sphincter to hold it back.
The stagnant urine that remains in the bladder creates a breeding ground for bacteria, leading to recurrent urinary tract infections (UTIs). If the condition is left unmanaged, the constant backup of urine can increase pressure within the kidneys, potentially leading to significant kidney damage or even failure over time.
The Diagnostic Process
Confirming a diagnosis of atonic bladder begins with a thorough medical history and a physical examination. A healthcare provider will discuss symptoms and any underlying health conditions, such as neurological disorders, that could be a contributing factor.
A key diagnostic test is the measurement of post-void residual (PVR) volume. This procedure uses an ultrasound scan on the lower abdomen to see how much urine is left in the bladder immediately after urination. Alternatively, a catheter may be temporarily inserted to drain and measure the remaining urine. A high PVR volume indicates that the bladder is not emptying effectively.
To gain a more detailed understanding, a doctor may order urodynamic studies to evaluate bladder function. During the study, the bladder is filled with sterile water through a small catheter, and pressure sensors measure its capacity and ability to contract, which can confirm the lack of detrusor muscle activity.
Imaging tests may be used to look for physical abnormalities. A cystoscopy involves inserting a thin tube with a camera into the urethra to visually inspect the lining of the bladder and urethra for blockages or other issues. An ultrasound of the kidneys may also be performed to check for any signs of damage caused by urine backing up from the bladder.
Management and Treatment Approaches
The primary goal of managing an atonic bladder is to ensure the bladder is emptied regularly to prevent complications. The most common and effective method for this is intermittent self-catheterization (ISC). This technique requires the individual to insert a clean, disposable catheter through the urethra into the bladder to drain the urine completely. This procedure is performed several times a day on a set schedule to provide control and prevent bladder overdistension.
For individuals unable to perform ISC, an indwelling catheter is an alternative. This involves a catheter that remains in the bladder for an extended period. A Foley catheter is inserted through the urethra, while a suprapubic catheter is inserted directly into the bladder through a small incision in the abdomen.
While not the main solution, medications may be tried to support bladder function. Drugs like bethanechol are intended to help stimulate bladder contractions, but their effectiveness in cases of true atonic bladder is often limited. Their use is secondary to a consistent bladder drainage routine.
Surgical interventions are reserved for specific situations where other techniques are not suitable. A procedure called a sphincterotomy may be performed to weaken the bladder outlet muscle, making it easier for urine to drain, though this often results in incontinence. In severe cases, a urinary diversion may be created, which involves surgically rerouting the ureters to an opening (stoma) on the abdomen, from which urine is collected in an external bag.