Urinary Incontinence Disease Background

Introduction

Urinary incontinence (UI) is a complaint of involuntary urine leakage.

Epidemiology

Urinary incontinence is a common condition and increases in prevalence with age, affecting both sexes.  The prevalence of urinary incontinence in older adults was 13%, as seen in several studies conducted in different regions of Asia.  

In women, its prevalence peaks around menopause and rises steadily into later life. In men, the prevalence is much lower than in women, with no spikes in prevalence. 

Pathophysiology

Maintenance of continence is noted when the urethral closure pressure exceeds the detrusor pressure. Incontinence may be caused by bladder dysfunction, sphincter dysfunction or a combination of both. There are several changes in the lower urinary system related to aging such as decreased bladder capacity with a feeling of fullness, decreased rate of detrusor muscle contraction, decreased pelvic floor resistance and increased residual urine volume that can cause urinary incontinence.  

In women, the bladder and urethra are supported by the anterior vaginal wall. Menopausal women, due to their decrease in estrogen and collagen, have a reduced elasticity of the of the detrusor muscle of the ductus arteriosus and atrophic changes in the pelvic floor muscle. 

Risk Factors

Reversible Factors  

Reversible risk factors include: 

• Body mass index >30 kg/m²
• Smoking
• High caffeine intake
• Participation in high-impact sports
• Diabetes
• Depression
• Central nervous system (CNS) disorders
• Recurrent urinary tract infection (UTI)
• Constipation
• Drugs (eg alpha agonists, alpha₁ blockers, angiotensin-converting enzyme [ACE] inhibitors, antiarrhythmics, anticholinergics, antidepressants, antihistamines, antimuscarinics, antipsychotics, benzodiazepines, beta₃ agonists, decongestants, diuretics, estrogens, opioids, skeletal muscle relaxants, spasmolytics)
• Pelvic organ prolapses
• Environmental barrier

Irreversible Factors  

Irreversible risk factors include:

• Increasing age
• Race
• Educational attainment
• Family history
• Childhood nocturnal enuresis or daytime wetting
• Multiparity
• Forceps delivery
• Menopause
• Hysterectomy
• Surgery for pelvic organ prolapse

Classification

Major Types  

Stress Urinary Incontinence  

Stress urinary incontinence is involuntary urine leakage on effort or exertion or when coughing or sneezing. This occurs during increased intraabdominal pressure that overcomes the sphincter mechanism in the absence of bladder contraction. Irritative voiding symptoms and nocturia are absent. This may be caused by poor pelvic support or intrinsic sphincter deficiency.  

Complicated stress UI includes a history of recurrent urinary tract infections (UTIs), previous pelvic floor repairs, or concurrent urge- or voiding dysfunction-related symptoms. Stress UI in men is primarily associated with surgery of the prostate.  

Urge Urinary Incontinence  

Urge urinary incontinence is involuntary urine leakage due to detrusor overactivity, associated with or immediately preceded by urgency. Patients are unable to hold back their urine when they feel the intense need to void. This may be caused by detrusor myopathy, neuropathy, bladder cancer, stones or infections.  

Mixed Urinary Incontinence  

Mixed urinary incontinence is involuntary urine leakage associated with both urgency and exertion, effort, coughing or sneezing. This is present when the bladder outlet is weak, and detrusor is overactive.  

Overflow Incontinence  

Overflow incontinence is also referred to as “incomplete emptying”, which describes the dribbling or continuous leakage associated with incomplete bladder emptying. This may be caused by bladder overdistention, impaired detrusor contraction and/or bladder outlet obstruction. Associated symptoms include weak urinary stream, intermittency, hesitancy, frequency and nocturia.

Incontinence Related to Reversible Medical Conditions  

Transient Incontinence  

Transient incontinence arises from an acute medical condition affecting the lower urinary tract. Symptoms resolve when the medical condition is addressed and treated.  

Functional Incontinence  

Functional incontinence arises from chronic impairment of physical and/or cognitive functioning. This is a diagnosis of exclusion. Symptoms may resolve by improving the patient’s functional status, treating comorbidities and changing medications.  

Overactive Bladder (OAB) Syndrome  

Overactive bladder syndrome is urgency with or without urge incontinence usually accompanied by complaints of frequency and nocturia and without UTI or other obvious pathology. 

Urinary Incontinence_Disease Background