Overview

Definition

Urinary incontinence is loss of bladder control, leading to involuntary loss of urine or uncontrolled urine leakage, which presents a hygienic or social problem to the individual and impacts quality of life.

Epidemiology

• Women > men
• Prevalence ↑ with age
• Both genders are equally affected after 80 years of age.
• In the United States, 20 million women and 6 million men experience urinary incontinence (UI) during their lifetime.
• Globally, approximately 35% of individuals > 60 years of age suffer from UI.
• Up to 80% of women in nursing homes have UI.
• Only 25% of individuals affected by UI seek treatment due to the social stigma.

Etiology and risk factors

• History of multiple pregnancies
• Current pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-HCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care
• Vaginal delivery
• Damage due to surgery or trauma near/on the bladder or pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor
• Prostate surgery
• Menopause
• Conditions affecting the brain or spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord, such as: 
  • Stroke 
  • Multiple sclerosis Multiple Sclerosis Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease that leads to demyelination of the nerves in the CNS. Young women are more predominantly affected by this most common demyelinating condition. Multiple Sclerosis 
  • Parkinson disease
  • Cerebral palsy Cerebral palsy Cerebral palsy (CP) refers to a group of conditions resulting in motor impairment affecting tone and posture and limiting physical activity. Cerebral palsy is the most common cause of childhood disability. It is caused by a nonprogressive CNS injury to the fetal or infant brain. Cerebral Palsy
• Diabetes mellitus Diabetes mellitus Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
• Chronic renal disease 
• Obesity
• Urinary tract infections Urinary tract infections Urinary tract infections (UTIs) represent a wide spectrum of diseases, from self-limiting simple cystitis to severe pyelonephritis that can result in sepsis and death. Urinary tract infections are most commonly caused by Escherichia coli, but may also be caused by other bacteria and fungi. Urinary Tract Infections 
• Medications:
  • Antipsychotics and antidepressants with anticholinergic Anticholinergic Anticholinergic drugs block the effect of the neurotransmitter acetylcholine at the muscarinic receptors in the central and peripheral nervous systems. Anticholinergic agents inhibit the parasympathetic nervous system, resulting in effects on the smooth muscle in the respiratory tract, vascular system, urinary tract, GI tract, and pupils of the eyes. Anticholinergic Drugs properties
  • Alpha-adrenergic agonists
  • Alpha antagonists
  • Diuretics
  • Calcium channel blockers Calcium Channel Blockers Calcium channel blockers (CCBs) are a class of medications that inhibit voltage-dependent L-type calcium channels of cardiac and vascular smooth muscle cells. The inhibition of these channels produces vasodilation and myocardial depression. There are 2 major classes of CCBs: dihydropyridines and non-dihydropyridines. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers) 
  • Sedative hypnotics
  • Angiotensin-converting enzyme inhibitors
  • Medications against Parkinson disease
• Constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation
• ↑ Alcohol or caffeine intake
• ↑ Age

Consequences of urinary incontinence

• Increased: 
  • Rates of depression and social isolation 
  • Hospitalizations 
  • Urinary tract infections Urinary tract infections Urinary tract infections (UTIs) represent a wide spectrum of diseases, from self-limiting simple cystitis to severe pyelonephritis that can result in sepsis and death. Urinary tract infections are most commonly caused by Escherichia coli, but may also be caused by other bacteria and fungi. Urinary Tract Infections
  • Pressure ulcers 
  • Admission to long-term residential care 
• Decreased:
  • Work productivity 
  • General health
  • Quality of life 

Pathophysiology

Normal bladder function

• The bladder has 2 main functions: 
  • Store urine 
  • Expel urine 
• Bladder function is controlled by:
  • Detrusor muscle → contracts during voiding 
  • Urethral sphincter → contracts during filling
• The bladder is innervated by the parasympathetic, sympathetic, and voluntary nervous systems.
• During filling:
  • Sympathetic stimulation → detrusor muscle relaxation
  • Contraction of the bladder neck
  • Contraction of the external urinary sphincter
• During voiding:
  • Bladder distention → activation of mechanoreceptors → afferent signals to the pons
  • Inhibition of sympathetic stimulation and relaxation of the bladder neck
  • Parasympathetic activation of the detrusor 
• ↑ Intra-abdominal pressure is transmitted to the urethra and bladder equally, which results in continence.
• The urethra is supported by the pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor muscles, which help to close the urethral opening.
• Damage to the balance between the detrusor muscle and the urethral sphincter contributes to UI.

Incontinence pathophysiology

• Stress incontinence:
  • Leakage of urine due to effort or exertion
  • Intra-abdominal pressure > bladder sphincter pressure
• Urge incontinence: overactivity of the detrusor muscle
• Mixed incontinence: combined detrusor muscle and bladder sphincter pathology
• Overflow incontinence:
  • A bladder outlet obstruction or impaired detrusor contractility cause incomplete bladder emptying.
  • Inability to void the bladder completely → urinary retention → overdistension of the bladder → continuous or frequent loss of urine
• Functional incontinence:
  • Inability to control urine voiding due to a physical or mental impairment 
  • No organic cause 

Clinical Presentation

General approach

Focus the history on symptoms consistent with incontinence based on the type of circumstance:

• ↑ Daytime frequency of urination
• Hesitancy (difficulty to initiate voiding)
• Urge to void, but leakage before reaching the restroom
• Disruption in daily activities due to urine leakage 
• Leakage of urine postsurgery 
• Feeling of dampness in the undergarment without the feeling of urine leakage
• Feeling of incomplete voiding 
• Nocturia 
• Nocturnal enuresis Enuresis The elimination disorders that most commonly occur in childhood are enuresis (urinary incontinence) and encopresis (fecal incontinence in inappropriate situations). Enuresis is usually diagnosed when children > 5 years of age continue to wet the bed. Enuresis can occur both in the daytime (diurnal) and at night (nocturnal). Elimination Disorders (leakage of urine when asleep)
• For individuals who have difficulty recalling or quantifying symptoms:
  • Bladder diary:
    • Fluid intake 
    • Frequency of voiding 
    • Urine volume
    • Number of episodes of incontinence
  • Pad test: 
    • The individual is asked to wear a pad.
    • The volume of urine leaked is checked by the weight and the number of pads used per day.

History

• Stress incontinence:
  • Leakage of urine due to effort or exertion
  • When the event causing ↑ intra-abdominal pressure stops (e.g., coughing), small leakages stop.
  • Associated with pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-HCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care, childbirth, constipation, and obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity
• Urge incontinence:
  • Sudden and unexpected need to void urine
  • Associated with:
    • Overactive bladder syndrome → urinary urgency occurs with or without incontinence
    • Cystitis
    • Multiple sclerosis Multiple Sclerosis Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease that leads to demyelination of the nerves in the CNS. Young women are more predominantly affected by this most common demyelinating condition. Multiple Sclerosis
    • Stroke
    • Parkinson disease
    • Prostate hyperplasia
• Mixed incontinence: Involuntary leakage is associated with urgency and stress incontinence.
• Overflow incontinence:
  • Urinary retention or incomplete bladder emptying 
  • Continuous or frequent loss of urine
  • May result from:
    • Pelvic/abdominal surgery 
    • Enlarged prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. Prostate and other Male Reproductive Glands
    • Pressure on the urethra by a tumor
    • Urethral stricture 
    • Constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation
    • Pregnancy
    • Medication 
    • Neurological impairment
• Functional incontinence:
  • Cognitive or physical factors impairing the individual’s ability to reach or use the restroom.
  • Associated with:
    • Impaired mobility or dexterity
    • Dementia/cognitive impairment 
    • Confusion
    • Poor eyesight 
    • Poor environment or a change in environment (e.g., hospitalization)

Physical examination

• Pelvic exam to check for: 
  • The integrity of pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor muscles
  • Vaginal atrophy
  • Pelvic organ prolapse Pelvic Organ Prolapse Pelvic organ prolapse (POP) is a general term that refers to herniation of 1 or more pelvic organs (e.g., bladder, uterus, rectum) into the vaginal canal, and potentially all the way through the introitus. Weakness and insufficiency of the pelvic floor may result in POP. Pelvic Organ Prolapse
  • Digital exam for pelvic/uterine masses
• Abdominal exam to palpate for pelvic and abdominal masses
• Rectal exam: 
  • Determine the size and consistency of the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. Prostate and other Male Reproductive Glands gland.
  • Exclude stool impaction.
  • Examine for rectal mass.

Diagnosis

Laboratories

• Urinalysis: 
  • To exclude urinary tract infection
  • To exclude the presence of blood in the urine
  • To exclude the pathologic presence of protein or cells requiring further evaluation
• Blood: 
  • Creatinine 
  • Blood urea nitrogen 
  • Estimated glomerular filtration rate Glomerular filtration rate The volume of water filtered out of plasma through glomerular capillary walls into bowman's capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests 

Clinical tests

• Bladder stress test:
  • Full bladder
  • Ask the individual to cough or bear down while standing.
  • Observe any urine leakage.
• Measurement of postvoid residual urine: 
  • An assessment of urine left in the bladder after voiding (by ultrasound or straight catheter)
  • Abnormal: > 150 ml or ⅓ of prevoid volume
• Urodynamic tests measure the pressure the bladder/urinary sphincter muscle can withstand, and the flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure of urine:
  • Cystometry: measures pressure and volume of fluid in the bladder during filling, storage, and voiding
  • Uroflowmetry: measures the rate of urine flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure
  • Urethral pressure profile: tests urethral function
  • Leak point pressure: determines the bladder or abdominal pressure when leakage occurs

Radiology

• Not always necessary
• Pelvic ultrasound: 
  • To detect tumors 
  • To detect nephrolithiasis Nephrolithiasis Nephrolithiasis is the formation of a stone, or calculus, anywhere along the urinary tract caused by precipitations of solutes in the urine. The most common type of kidney stone is the calcium oxalate stone, but other types include calcium phosphate, struvite (ammonium magnesium phosphate), uric acid, and cystine stones. Nephrolithiasis 
  • To check urine volume before and after voiding
• Cystoscopy: A thin tube with a camera is passed through the urethra and into the bladder.
• Abdominal CT: rule out masses/infection (e.g., renal carcinoma, pyelonephritis Pyelonephritis Pyelonephritis is infection affecting the renal pelvis and the renal parenchyma. This condition arises mostly as a complication of bladder infection that ascends to the upper urinary tract. Pyelonephritis can be acute or chronic (which results from persistent or chronic infections). Typical acute symptoms are flank pain, fever, and nausea with vomiting. T Pyelonephritis and Perinephric Abscess)
• Spinal MRI: rule out cord compression, cauda equina, and spinal abscess