Introduction
Bladder sphincter dyssynergia is also referred to as detrusor sphincter dyssynergia. It refers to various lower urinary tract symptoms caused due to detrusor muscle contraction with an involuntary contraction of the urethral sphincter muscle. In normal conditions, these muscles function in synergistic coordination. Dyssynergia can occur in any individual affected with neurological lesions.
What Is Bladder Sphincter Dyssynergia?
The detrusor muscle is present in the wall of the bladder. It remains relaxed to store urine in the bladder and contracts to release urine during urination. The external and internal sphincter muscles envelop the urethra. The urethra closes when either of the muscles contract. It relaxes in coordination with the detrusor muscle to allow the exit of urine through the urethra.
A synergistic coordination between the bladder’s detrusor muscle and the urethral sphincter muscle is essential to maintain urinary function and urinary continence. The physiological micturition has a storage phase and the voiding phase. Voiding of urine requires coordination between the detrusor contraction and relaxation of the urethral sphincter muscles. Loss of this coordination is known as bladder sphincter dyssynergia or detrusor sphincter dyssynergia. It causes various urinary tract symptoms.
What Are the Causes of Bladder Sphincter Dyssynergia?
Bladder sphincter dyssynergia is caused by neurological lesions of the suprasacral spinal cord. The lesions can be due to the following causes:
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Spinal cord injury.
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Multiple sclerosis (covering of the nerve cells are damaged).
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Myelodysplasia (a rare type of blood cancer).
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Congenital abnormalities like neural tube defects, spinal dysraphism, and spina bifida,
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Infections of the spinal cord dyssynergia.
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Stroke.
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Transverse myelitis (inflammation of both sides of a section of the spinal cord).
Spina bifida, spinal cord injuries, and multiple sclerosis are common pathologies that cause detrusor sphincter.
What Are the Types of Bladder Sphincter Dyssynergia?
Detrusor sphincter dyssynergia is divided into three types:
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Type 1: This condition presents with simultaneous contraction of the detrusor muscle and the sphincter muscle tightening. Urination occurs due to sudden relaxation of the sphincter muscle during the detrusor contraction.
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Type 2: Dyssynergia is due to the sporadic contraction of the external urethral sphincter during the entire detrusor contraction.
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Type 3: Dyssynergia is due to a crescendo-decrescendo pattern of sphincter muscle contraction resulting in the obstruction of the urethra during the entire detrusor contraction.
The type of dyssynergia is based on the type and degree of the spinal cord injury. Bladder sphincter dyssynergia is less common in individuals with cervical-level lesions than lower-level spinal cord lesions. Incomplete neurological lesions cause type 1 dyssynergia, and complete neurological lesions cause type 2 and type 3 dyssynergia.
How Does Bladder Sphincter Dyssynergia Occur?
Physiological micturition occurs in two phases, the storage phase and the voiding phase. In the storage phase, the bladder undergoes positive filling. The voiding phase is the elimination of urine by synergistic coordination between the detrusor muscle and the sphincter muscle. This physiological process is controlled by the central nervous system. Sympathetic activation during the filling of the bladder stimulates the contraction of the internal sphincter and the closure of the bladder.
The proximal urethral pressure should be greater than the pressure within the bladder during the storage phase to maintain continence. This increase in urethral pressure is due to the stimulation of external and internal sphincters by hypogastric and pudendal nerves, respectively. This reflex is suppressed by the pontine micturition center through the spinobulbospinal tract during the urge to void urine. This inhibits sympathetic activation, causing relaxation of the external sphincter muscles, thereby decreasing the urethral pressure and allowing the exit of urine. Spinal cord injury or other neurological lesions disrupt the central nervous system regulation of the micturition center, resulting in incoordination between the detrusor muscle and the sphincter muscle.
What Are the Symptoms Associated With Bladder Sphincter Dyssynergia?
Bladder sphincter dyssynergia causes lower urinary tract symptoms which include the following:
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Chronic urinary retention.
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Intermittent voiding of urine.
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Irregular and low-volume voiding.
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Urinary incontinence without an urge to void urine.
What Are the Complications Associated With Bladder Sphincter Dyssynergia?
If left untreated, bladder sphincter dyssynergia can cause urologic complications. The following are the complications caused by bladder sphincter dyssynergia:
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Urinary tract infection or urosepsis.
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Vesicoureteric reflux.
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Upper urinary tract deterioration.
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Hydronephrosis.
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Urolithiasis.
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Renal insufficiency.
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Bladder damage.
The complications are less common in females because the detrusor pressure generated is usually low in females compared to that created in men. Elevated detrusor pressure causes hydronephrosis and renal deterioration resulting in renal failure.
How Is Bladder Sphincter Dyssynergia Diagnosed?
The diagnostic procedures are performed to diagnose the nature of bladder dysfunction and the underlying cause. It includes the following:
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Radiographic Imaging - Ultrasonography and CT (computed tomography) scans help in assessing post-void residual urine volume, urinary calculi, reflux, and hydronephrosis. However, they do not help in specifically diagnosing bladder sphincter dyssynergia.
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Urodynamic Study - Urodynamic study is performed with or without fluoroscopy through electromyography, voiding cystourethrogram, urethral pressure, or video dynamics. Cystoscopy is performed to rule out urethral strictures.
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Other Tests - A urine culture test is performed if a urinary tract infection is suspected. Serum electrolytes, urea, and creatinine are also measured. A 24-hour urine voiding record is analyzed to characterize the voiding dysfunction.
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Sacral Neuromodulation - It is an effective early therapy. However, it remains unproven.
How Is Bladder Sphincter Dyssynergia Treated?
The main aim of bladder sphincter dyssynergia is to achieve adequate storage and emptying capacity of the bladder to protect renal function, improve patient safety, and optimize the quality of life. Type 1 dyssynergia is managed with watchful waiting. Type 2 and 3 are treated with the following strategies;
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Medications - Drugs like alpha-blockers are given to reduce post-void residual volumes and increase voided volumes. Clean intermittent self-catheterization combined with antimuscarinics is given to reduce detrusor contractions and pressures. This improves the storage and emptying capacity of the bladder.
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Self-Catheterization or Indwelling Catheters: Theseare also recommended.
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Botulinum Toxin Injections: Theseare recommended if conservative treatment is not effective.
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External Sphincterectomy: It is a therapeutic, surgical procedure that destroys the external sphincter. However, it is also associated with complications like incontinence, recurrent infections, erectile dysfunction, stenosis, strictures, and epididymitis.
Conclusion
Bladder sphincter dyssynergia is a condition in which high bladder pressure results in bladder damage and voiding dysfunction. Hence, individuals with lower urinary tract symptoms must consult the doctor for an earlier diagnosis. Timely intervention helps in treating the condition and prevents the risk of complications.
