Elimination
CONCEPT 15: Elimination
Tammy Williams
Elimination is a concept that has various applications across multiple disciplines, including mathematics, economics, chemistry, and biology. From a biologic perspective, elimination is a concept applicable to all living organisms—from the smallest of microbes to plants, animals, and humans. This concept presentation focuses on elimination as a physiologic concept, as it applies to humans and includes normal or expected elimination patterns and problems associated with elimination.
DEFINITION
Broadly speaking, the term elimination refers to the removal, clearance, or separation of matter. From a human physiologic perspective, the term elimination is defined as the excretion of waste products.1 The human body eliminates various forms of waste through the skin, kidneys, lungs, and intestines. This concept presentation focuses on elimination of waste from the urinary system and the gastrointestinal system. For the purposes of this concept presentation, bowel elimination is defined as the process of expelling stool (also referred to as feces). Terms used to describe the process of bowel elimination include defecation, defecate, or bowel movement. Urinary elimination is defined as the process of expelling urine. Terms used to describe this process include micturition or urination. The term continence refers to the purposeful control of urinary or fecal elimination.
Impaired elimination refers to one or more problems associated with the elimination process. There are many terms associated with impaired urinary elimination including anuria (absence of urine), dysuria (painful urination), polyuria (multiple episodes of urination, as with diabetes), urinary frequency (multiple episodes of urination with little urine produced in a short period of time), and urinary hesitancy (the urge to urinate exists, but the person has difficulty starting the urine stream).
SCOPE
The scope of this concept includes the normal or expected physiologic process of waste formation and excretion by the gastrointestinal and renal systems as well as problems associated with this process (Fig. 15.1). Each of these body systems are complex and differ significantly from an anatomic and physiologic perspective. The kidneys are responsible for the removal of metabolic waste and other elements from the blood in the form of urine, and the gastrointestinal tract is responsible for the removal of digestive waste in the form of stool. Despite these differences, similarities are clear when considering this from a conceptual lens. In both systems, the process involves the formation and excretion of waste. The scope of this concept also includes impairment of urinary and bowel elimination, representing a wide range of problems and conditions.
NORMAL PHYSIOLOGICAL PROCESS
Because of the significant differences between urinary and bowel elimination, an overview of the normal physiologic process for each is presented separately.
Normal Urinary Elimination
Urinary elimination involves the process of waste formation (production of urine) and the excretion of urine involving several specific structures. The kidneys, ureters, bladder, and urethra must all function adequately for normal urination to occur.
Formation of Urine
The removal of metabolic waste from the blood by the urinary system represents an essential process needed to maintain physiologic homeostasis and regulation. The main functional unit of the kidneys is the nephron; each kidney has more than 1 million nephrons. Each nephron is composed of two parts—blood vessels and renal tubules. Optimal physiologic effect depends on continuous perfusion of a large volume of blood (an average of 1 L/min) to the kidneys and functioning nephrons.
The formation of urine is complex and involves three main processes: glomerular filtration, tubular reabsorption, and tubular secretion. Blood enters the kidney through the renal artery, which then branches into progressively smaller arteries, arterioles, and, finally, a cluster of capillaries known as the glomerulus (Fig. 15.2). The glomerulus is a semipermeable membrane that serves to filter blood into a C-shaped structure of the renal tubule known as the Bowman capsule. This process (glomerular filtration) represents the beginning of urine formation.
FIG. 15.1 Scope of Elimination.
FIG. 15.2 The Nephron. Modified from Patton, K. T., & Thibodeau, G. A. [2014]. The human body in health and disease [6th ed.]. St Louis: Mosby.
The filtrate contains water, electrolytes, and waste that have been removed from the blood. As the filtrate passes through a sequence of renal tubules (from the Bowman capsule to the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule; see Fig. 15.2), a network of capillaries surrounding the renal tubules reabsorb most of the water, electrolytes, and other necessary elements back into the blood. This process is referred to as tubular reabsorption. The third process, tubular secretion, involves a secondary process for small amounts of select substances (e.g., potassium, hydrogen, ammonia, and drugs) to be moved from the blood in the capillaries surrounding the tubules into the tubules. The amount of water and electrolytes reabsorbed into the blood or excreted in the renal tubules is controlled by several hormones, particularly aldosterone, antidiuretic hormone, parathyroid hormone, renin, and atrial natriuretic factor.
Excretion of Urine
Urine formed in the renal tubules moves into the collecting duct and then into the renal pelvis, the ureter, and the bladder, where it is stored until urination occurs (Fig. 15.3). The bladder holds approximately 300 to 500 mL in adults (much less volume in children) before the pressure stimulates stretch receptors in the bladder wall. The stretch receptors send nerve impulses through the spinal cord to signal the need for urination. An internal sphincter, composed of smooth muscle, contracts involuntarily to prevent urine from leaking out of the bladder. The external sphincter, located just below the internal sphincter and surrounding the upper part of the urethra, is composed of skeletal muscle and is voluntarily controlled. Thus, the process of urination involves a series of nerve signals between the bladder and spinal cord to trigger the micturition reflex; this causes the internal sphincter muscles to relax and bladder wall contraction. With the voluntary relaxation of the external urinary sphincter, urine passes out of the body through the urethra. The external urinary sphincter must be under the individual’s control for urinary control (continence) to be successful.
FIG. 15.3 Urinary Elimination. From Ignatavicius, D. D., & Workman, M. L. [2021]. Medical surgical nursing: Patient-centered collaborative care [10th ed.]. St. Louis: Elsevier.
Normal Bowel Elimination
Digestion and the Formation of Stool
The gastrointestinal system has two overarching functions: the breakdown and absorption of nutrients from foods ingested and the elimination of waste from this process. The gastrointestinal system extends from the mouth to the anus. The first part of the gastrointestinal tract (mouth, esophagus, stomach, and small intestines) is involved in the digestion and absorption of nutrients, a process that also involves other digestive organs, including the liver, gallbladder, and pancreas (Fig. 15.4). The digestive process is described further in Concept 14, Nutrition.
The process of waste formation occurs in the colon. The waste product, known as stool or feces, are comprised of water, bile, undigested food matter, unabsorbed mineral, bacteria, mucous, and epithelial cells from the lining of the intestines. Smooth muscles within the intestinal tract stimulate peristalsis, which helps move the fecal matter through the gastrointestinal tract. The large intestine, which is 5 or 6 feet long and approximately 2 inches in diameter, has four parts: the cecum (and appendix), the colon, the rectum, and the anus (see Fig. 15.4). The function of the large intestine is to absorb water and electrolytes as fecal matter moves through its walls. Mucus in the intestine helps lubricate the walls and aids in the expulsion of the stool. If there is excessive peristalsis and the stool moves through the large intestine quickly, less water is absorbed, resulting in a loose stool. If the peristalsis is reduced, feces pass through the large intestine slowly, resulting in greater absorption of water and a harder stool.2
FIG. 15.4 The Gastrointestinal Tract. From Wilson, S., & Giddens, J. [2022]. Health assessment for nursing practice [7th ed.]. St Louis: Elsevier.
Elimination of Stool
The process of expelling stool is referred to as defecation, which is a reflexive action involving both voluntary and involuntary control. When the stool reaches the rectum, pressure stimulates parasympathetic nerve fibers in the sacral aspect of the spinal cord, which then produces contraction of the rectum with a relaxation of the internal anal sphincter. These actions result in an urge to defecate. The urge to defecate can be suppressed until the person is in an appropriate environment. At that time, the individual voluntarily relaxes the external anal sphincter to allow passage of the stool.
Age-Related Differences
Infants, Toddlers, and Children
Patterns of elimination change in the first few years of life. Infants and toddlers initially lack control over the sphincters and muscles that control urination and bowel elimination, but control is attained during early childhood as a normal developmental milestone. Children are typically 18 to 24 months of age before they are able to identify the urge to urinate and defecate.3 Toilet training by the parent or caregiver helps the child obtain conscious control of his or her bowel and bladder functions. Most children are ready for “potty training” between ages 2 and 3.3
Pregnant Person
Pregnancy can affect elimination patterns because the fetus in the abdominal cavity affects both bowel and bladder function. As the fetus grows, increased pressure is placed on the bladder, and frequent urination is required. The pregnant individual will have larger volumes of urine because of greater blood volume during the gestation. The growing fetus can also interfere with intestinal peristalsis and can cause constipation. The use of prenatal vitamins with iron can also contribute to constipation in the pregnant female.4
Older Adults
A number of physiologic changes associated with aging affect elimination. By age 80 years, renal blood flow reduces to an estimated 600 mL/min, and the kidneys lose up to 50% of functioning nephrons for a variety of reasons, including changes in size of the kidney and sclerosis. In the absence of disease, this does not change the older adult’s ability to produce urine sufficiently to maintain normal composition of body fluids, although it represents reduced renal reserve, making the older adult more susceptible to fluid and electrolyte imbalances and kidney damage due to medications. Although the bladder retains tone with age, the volume of urine that can be held reduces, leading to urinary frequency. In many older adults, muscles around the urethra become weak, thus increasing the risk of incontinence.
Age-related changes affecting bowel elimination include atrophy of smooth muscle layers in the colon and reduced mucous secretions. Reduced tone of the internal and external sphincter as well as reduced neural impulses (reducing the sensation of bowel evacuation) can make the older adult more susceptible to constipation or incontinence.
VARIATIONS AND CONTEXT
Alterations in elimination can occur with urinary or gastrointestinal function and represent a wide spectrum of problems. Most problems and conditions can be grouped by common themes and include incontinence, retention, discomfort, infections and inflammation, neoplasms, and organ failure.
Control
The ability to control the elimination of urine and stool is an important physiologic function. The term incontinence refers to the loss of control of either urine or bowel elimination. Control issues arise as a result of undeveloped elimination mechanisms, malfunctions in the mechanism of elimination, alterations in cognition, or with significant urge and the inability to access a bathroom. Nearly all individuals experience either fecal or urinary incontinence during their lifetime. Individuals who are incontinent are at risk for skin breakdown (particularly if bedridden) and can potentially experience changes in daily activities, functional activities, and social relationships.
Urinary incontinence is a disruption in the storage or emptying of the bladder with involuntary release of urine usually associated with dysfunction of the external and/or internal urinary sphincters.5 It can range from light urine leakage when coughing or laughing (stress incontinence) to full loss of continence. Factors affecting urinary incontinence may be psychological or physical, such as depression, anxiety, cognitive impairments, or acute injury or surgical procedures.6,7 Types of urinary incontinence are listed in Table 15.1.
Fecal incontinence is the involuntary passage of stool and ranges from an occasional leakage of stool while passing gas (flatus) to a complete loss of bowel control. Fecal incontinence most commonly occurs with diarrhea, particularly when it is associated with forceful intestinal peristalsis (cramping). Complete fecal incontinence occurs with the loss of sphincter control—usually as a result of traumatic injury, pathologic changes to the rectum, or neurologic injury. Fecal incontinence also can occur as a result of cognitive changes.8,9
Retention
Retention refers to the unintentional retention of urine or stool. Retention problems can occur at any age. The primary mechanisms causing retention are usually associated with obstructions, inflammation, or ineffective neuromuscular activation within the bladder or the gastrointestinal tract.
TABLE 15.1
Types of Urinary Incontinence
Type of Incontinence Description
Stress Leakage of small amounts of urine during physical movement (coughing, sneezing, exercising)
Urge Leakage of large amounts of urine at unexpected times, including during sleep
Overactive bladder Urinary frequency and urgency, with or without urge incontinence
Functional Untimely urination because of physical disability, external obstacles, or cognitive problems that prevent person from reaching toilet
Overflow Unexpected leakage of small amounts of urine because of full bladder
Mixed Usually occurrence of stress and urge incontinence together
Transient Leakage that occurs temporarily because of a situation that will pass (infection, taking a new medication, colds with coughing)
Urinary retention occurs as either incomplete emptying of the bladder after urination or a complete inability to urinate and is caused by a number of factors. Incomplete emptying can occur due to malfunction in nervous system innervation to the bladder or mechanical change in the shape of the bladder that causes retention.10 For example, women may experience urinary retention if there is hard stool that presses against the bladder or rectoceles or cystoceles that cause prolapse of the bladder and trapping of urine. Retention can also occur when an obstruction blocks the passage of urine (e.g., an enlarged prostate) or when the external sphincter of the bladder does not relax, allowing the urine to be expelled from the bladder. Medications that may cause urinary retention include antidepressants, anticholinergics, and antihistamines.11 Postoperative patients may have problems with urinary elimination as a result of the effects of anesthetics or the use of catheters during the surgical procedure. Psychosocial factors (e.g., fear or anxiety) may also affect the ability to successfully void.
Retention of stool occurs when the person is unable to pass stool successfully from the rectum. This condition is not normal for the young, but it may occur if the “urge to defecate” is ignored and stool becomes difficult to eliminate. Stool retention may occur as a side effect to many medications, including narcotic pain medications or can occur secondarily to reduced peristalsis or intestinal blockage. Stool retention usually results in constipation, defined as the difficult passage of hard, dry stool. Ongoing retention of stool causes loss of appetite, discomfort, and potentially fecal impaction.12
Discomfort
The process of elimination should normally be free of pain or discomfort; in the case of significant urgency, the process of elimination can actually relieve discomfort. The most common causes for urinary discomfort are associated with inflammation (often associated with infection) of the urinary tract or bladder distention associated with urinary retention. Pain associated with urinary tract infection (UTI) is often described as a burning pain. Pain also can be associated with irritation when urine comes in contact with lesions on the genitalia.
Common causes of discomfort associated with bowel elimination include constipation, excessive flatus, abdominal cramping, and diarrhea. Other causes of discomfort include inflammation or injury to the anus, the presence of hemorrhoids (both internal and external), anal fissure, and gastrointestinal infection or inflammation. Chronic conditions such as colitis or irritable bowel syndrome are also commonly associated with discomfort. In children, there can be telescoping of the bowel back into itself (intussusception) that can result in abdominal pain from obstruction and retention of stool.13
Infections and Inflammation
Elimination problems also can be caused by inflammatory or infectious conditions. Infection in the urinary system is often referred to as UTI, but specific structures in the urinary system can become inflamed or infected, including the kidney (nephritis), the renal pelvis (pyelonephritis), and the bladder (cystitis).
Acute intestinal inflammation and infection are most commonly associated with viral infections or food poisoning. Chronic inflammatory conditions of the intestinal tract include colitis and diverticulitis or autoimmune disorders. Inflammation and infections are usually associated with abdominal pain and discomfort (sometimes severe) and can potentially lead to nutritional deficits or intestinal perforation.
Neoplasms
Neoplasms are tumors and can have an effect on urinary and bowel elimination. Benign and malignant neoplasms of the prostate often lead to blockage of urinary flow in men. Tumors can also occur in the kidney or bladder, but these are less common. Neoplasms in the intestinal tract are also common and include benign growths (e.g., polyps) and cancerous lesions in the intestine, colon, or rectum.14
Organ Failure
One additional category of problems related to elimination is organ failure. The most obvious organ that comes to mind is the kidney. Renal failure can occur suddenly, usually associated with an injury to the kidney (referred to as acute kidney injury [AKI]), or it can occur as a slow, chronic process (referred to as chronic kidney disease [CKD]), whereby the kidneys lose functional capacity over months to years. The inability to remove metabolic waste and fluid creates significant physiologic challenges. The failure of other key organs, such as the heart, the liver, and the pancreas, also hampers elimination efforts. For example, heart failure and shock reduce blood flow to the kidneys and gastrointestinal system, thereby reducing the efficiency of urine production and removal as well as formation of stool. Removal of the small or large intestines because of injury or disease also results in significant changes in elimination.
CONSEQUENCES
A number of consequences occur associated with impaired elimination processes and are linked to the underlying problem.
• Consequences associated with incontinence range from the potential for skin breakdown and falls (if associated with urgency) to social, lifestyle, and relationship consequences and depression and withdrawal.
• The consequences of urinary retention include pain, chronic bladder infection, and bladder distention. Bladder distention can lead to urinary reflux (a backflow of urine from the bladder into the ureters), causing dilation of the ureters and renal pelvis, and can lead to pyelonephritis and renal atrophy.
• The complete loss of renal function represents significant physiologic consequences. The inability to remove toxins and metabolic waste results in fluid and electrolyte and acid–base disturbances and leads to death if untreated.
• The consequence of excessive fecal retention includes pain, loss of appetite, nausea, and vomiting.
• An ileus refers to a loss of peristaltic activity in the gastrointestinal tract. This can occur subsequent to abdominal trauma or surgery and is associated with nausea, vomiting, and distention. Although rare, rupture of the colon can occur, representing a life-threatening situation.
RISK FACTORS
Elimination represents normal physiologic function; thus, problems with the elimination of urine and stool and can affect any person regardless of age, gender, or race. It is a challenge to adequately summarize all risk factors for problems affecting elimination because each condition has its own unique risk factors. However, there are a few universal risk factors for the majority of problems affecting normal elimination. The single greatest risk factor for altered elimination is advanced age because of physiologic changes associated with aging process. Other general risk factors common to most elimination problems include individuals with altered cognition, impaired mobility, the debilitated, injuries or pathology affecting the neurologic system, spine, or pelvic organs. There is also a high correlation between some elimination problems—urinary and fecal incontinence, as one example.15 Also, many medications are known to cause changes in elimination—general anesthesia16 and opioids as common examples. Table 15.2 presents specific risk factors for retention and incontinence.
ASSESSMENT
Assessment of elimination includes taking a history, conducting a physical examination, and performing diagnostic testing when problems are identified.
History
Conducting a history is the first step to understanding problems associated with elimination. Ask about patterns of urinary and bowel elimination, including frequency, appearance of stool and urine, and associated symptoms. Common symptoms directly related to elimination include alterations in elimination patterns; changes in the appearance, frequency, or quality of stool or urine; or discomfort and difficulty associated with elimination. A symptom analysis approach is helpful to fully understand the symptom. Determine whether there have been changes in diet, recent changes in health status (e.g., cognition, mobility, functional ability, or other medical conditions), and if there are new medications or changes in medications. Voluntary or involuntary (incontinence) emptying of the bowel or bladder also must be assessed to determine the impact of the condition on the individual. Adults of all ages should be asked about urinary continence because it is an underreported phenomenon.
TABLE 15.2
Common Risk Factors for Incontinence and Retention
Persistent Incontinence Retention
Urinary
Advanced age
Female
Menopause
Multiparity
Obesity
Smoking
Impaired mobility
Trauma or surgery pelvic region
Impaired cognitive, debilitated state
Neurologic disorders (such as stroke, spinal injury, brain tumor)
Advanced age
Male
Prostate enlargement, inflammation, or infection
Pelvic organ prolapse
Pelvic mass
Pelvic trauma/surgery
Medications (anticholinergics, sympathomimetics)
Fecal
Advanced age
Diarrhea
Impaired mobility
Impaired cognitive, debilitated state
Injury, chronic condition affecting rectal neuropathway
Advanced age
Female
Pregnancy
Lower income
Poorly educated
Sedentary lifestyle
Dehydration
Chronic conditions (inflammatory bowel syndrome, depression)
Medications (opioids, diuretics, antidepressants, aluminum-based antacids)
Examination Findings
Physical assessment incorporates four examination techniques: inspection, auscultation, palpation, and percussion.
Inspection
The abdomen is inspected for contour; abdominal or bladder distention is an abnormal finding. The genitalia are also inspected to examine the urinary meatus for evidence of redness, lesions, or discharge. Discharge from the urinary meatus is an abnormal finding and may suggest infection, especially if the patient reports pain with voiding. Observe the perianal area. The area should be free from redness or lesions; the presence of hemorrhoids or an anal fistula may be observed if the patient complains of pain with defecation.
Inspection also includes looking at a stool or urine sample if available. Urine should be clear and yellow with mild odor. Very dark urine may be indicative of dehydration, may be a side effect of medication, or may indicate the presence of blood. Stool should be brown and formed. Stools that are black and tarry in appearance often signal gastrointestinal bleeding. Loose stools or diarrhea may be associated with diet, inflammation, or infection.
Auscultation
Auscultation is limited to the abdomen to listen to bowel sounds. Bowel sounds should be heard in all four quadrants. An absence of bowel sounds may be associated with paralytic ileus; hyperactive bowel sounds may be noted with gastrointestinal inflammation or with an intestinal obstruction.17 Auscultation is not indicated in urinary assessment.
Palpation
Abdominal palpation is a physical examination technique for both urinary and bowel elimination. The abdomen should be soft and nontender with palpation over the entire abdomen and over the urinary bladder. Abdominal or urinary distention is considered an abnormal finding and may be associated with reduced peristalsis or retention of stool or urine.
Rectal palpation is done to assess the rectal sphincter and to examine for the presence of masses, lesions, or impacted stool. Digital palpation is also part of the prostate examination.17 Although this is not directly an examination associated with elimination, prostate enlargement can result from a tumor (benign or malignant) or inflammation; both can contribute to urinary retention.
Diagnostic Tests
There are a number of diagnostic tests associated with elimination. In general, the diagnostic tests are classified into one of three categories: laboratory, radiographic, and direct observation.
Laboratory Tests
Urinalysis
A urinalysis is one of the most common of all laboratory tests. It is useful for screening a number of conditions not associated with a problem in elimination and is obtained with either a sterile urine specimen or a clean-catch specimen. Bacteria indicate infection, whereas blood may indicate damage from infection or trauma to the urinary system. Urinary analysis that indicates the presence of bacteria or blood components in the urine may require further assessment of the urinary tract by a physician specialist in the field of urology.
Renal function tests
Laboratory tests assessing renal function include blood urea nitrogen, blood creatinine, and creatinine clearance tests. Creatinine and blood urea nitrogen are excreted entirely by the kidneys and, therefore, provide a measure of renal function.
Culture
Urine and stool cultures are relatively common laboratory tests. When a UTI is suspected, a urine culture determines the presence and type of organism causing the urinary infection. Stool cultures are indicated when a parasitic infection is suspected.
Occult blood
When blood is suspected in stool, an occult blood test is indicated. It also represents a basic screening that should be performed as part of a rectal examination. The presence of blood in the stool could be related to a gastrointestinal bleed (inflammation and infection), hemorrhoids, or tumors.
Pathology
A biopsy is a sample of tissue or cells that undergoes pathologic evaluation. A biopsy can be taken from the rectum, colon, bladder, or kidney. Biopsies provide information associated with tumors or with general organ function.
Radiographic Tests and Scans
Numerous radiographic tests are used to assess elimination. Common radiographic tests include x-rays, computerized tomography, magnetic resonance imaging, and ultrasound. These are used to detect a variety of problems, including the presence of an intestinal tumor, a congenital renal abnormality, or kidney stones. Angiography is used to assess renal blood flow and can detect renal artery stenosis.
Direct Observation Tests
The ability to directly observe internal organs can be accomplished with scopes. With regard to the Concept of Elimination, scopes can be used to visualize the colon (colonoscopy), the sigmoid colon (sigmoidoscopy), the bladder (cystoscopy), or the urethra or ureters (uroscopy).
Direct visualization of the colon is done for screening or diagnostic purposes for polyps, cancer, and inflammatory conditions such as Crohn’s disease. Direct visualization of the bladder or ureters is done with a special scope as part of diagnostic or surgical procedures.
Other Diagnostic Tests
Several special tests are available to evaluate urinary elimination, including bladder stress testing, uroflowmetry and other urine flow studies, and postvoid residual measurement through the use of bladder scans or postvoid catheterization.
CORE COMPETENCIES
Elimination
• Integrate evidenced-based knowledge from nursing and other sciences as it relates to supporting elimination.
• Using a person-centered approach, perform a clinically relevant assessment, recognizing actual or potential health problems related to elimination.
• Collaborate with the interprofessional team to establish mutual healthcare goals related to elimination management for individuals.
• Using a person-centered approach, implement interventions and evaluate the plan of care to address conditions associated with elimination.
• Educate individuals and families regarding self-care for health promotion, illness prevention, and illness management related to elimination conditions.
• Demonstrate clinical judgment founded on broad knowledge of elimination.
CLINICAL MANAGEMENT
Primary Prevention
Primary prevention measures are aimed at maintaining optimal health and preventing the onset of disease through the reduction of risks. The foundation of primary prevention efforts, as it relates to this concept, includes awareness of environmental factors, maintaining a healthy diet, hydration, physical activity, and following optimal toileting practices.
Environmental Factors
Avoidance of contaminated water and foods can assist in maintaining consistent bowel habits. Bacteria in water or food can cause diarrhea and colitis. Parasites can be present in water or food that is not properly prepared. Parasites not only can cause elimination problems but also can affect overall health. Laboratory testing can determine whether parasites are present in the gastrointestinal system that may be causing problems with bowel elimination.
Maintaining Hydration
Water is a key element for prevention of bowel and urinary elimination problems. Water is absorbed by the stool to soften it and promote intestinal motility, which assists in the elimination of stool. Water serves the urinary system in that it increases volume, reduces bladder irritation, and helps eliminate toxins from the body.
Dietary Fiber
Fiber intake has been shown to prevent stool retention, especially when combined with adequate water intake and exercise. Fiber creates enough friction along the bowel surface that it can assist in the production of a bowel movement. Adequate fluid intake with the fiber is imperative. Fiber should be slowly added to the diet to prevent abdominal discomfort and excessive gas formation in the intestine. The U.S. Food and Drug Administration recommends 28 g of fiber/day, based on a 1000 kcal diet.18
Physical Activity
Physical activity is known to increase intestinal peristalsis which reduces the time for food matter to move through intestines. By decreasing the time it takes feces to move through the large intestine, less water is reabsorbed. For this reason, exercise helps prevent constipation.12
Maintenance of Regular Toileting Practices
Maintaining a consistent time of defecation is important in the regulation of bowel movements. The use of familiar toileting facilities may also encourage defecation. Avoidance of foods that cause discomfort during digestion and absorption or are known to cause constipation can also help maintain regular patterns of bowel elimination. To prevent urinary incontinence or retention, there should be timely and complete emptying of the bladder. Holding urine should be discouraged because this encourages bacterial growth in the bladder and consequent UTI.
Secondary Prevention (Screening)
Two common screening tests associated with elimination are screening for occult blood and colonoscopy—both are considered effective for the detection of colon cancer. The U.S. Preventive Services Task Force (USPSTF) recommends screening for colorectal cancer beginning at age 50 years until 75 years of age (recommendation grade A).19 The two categories of screening are stool-based tests and direct visualization tests. Stool-based tests (guaiac-based fecal occult blood test, fecal immunochemical test, or multitargeted stool DNA test) are recommended annually; the guaiac-based test is routinely done as part of a rectal exam. Direct visualization tests include colonoscopy or sigmoidoscopy. These are recommended every 10 years (or more often with certain risk factors). Such tests allow direct visualization of the colon and removal of precancerous lesions, averting the development of colon cancer.
Screening for prostate cancer is the only screening associated with urinary elimination. The recently revised recommendation is for periodic prostate-specific antigen (PSA)-based screening of men ages 55 to 69 to be an individualized decision, after weighing risks and benefits associated with screening with their healthcare provider (recommendation grade C). The USPSTF recommends against screening for prostate cancer in men over the age of 70.20 The USPSTF reports insufficient evidence to support routine screening for bladder cancer.21
Collaborative Interventions
Problems with elimination represent a wide range of conditions involving two major body systems—the gastrointestinal system and the urinary system. For the purposes of this concept, common interventions are only briefly described; detailed information is available in various nursing textbooks.
Clinical Nursing Skills for Elimination
• Assessment
• Urinary catheterization
• Suprapubic catheter care
• Catheter irrigation
• Enema
• Nasogastric tube for gastric decompression
• Ostomy care
• Medication administration
Pharmacologic Agents
Antibiotics
Infections of the kidney and urinary tract are treated with antibiotics. Antibiotics are selected based on the results of culture and sensitivity testing and the provider’s best judgment. Although a variety of agents are used, trimethoprim, trimethoprim with sulfamethoxazole, or nitrofurantoin are commonly prescribed for UTIs; parenteral antibiotics are indicated for more severe infections such as pyelonephritis. Antibiotics may also be used prophylactically with urinary retention or recurrent UTI.
Diuretics
Diuretics increase the volume of urine produced along with excreting sodium and potassium from the body by affecting the water resorption in the renal tubules. Loop diuretics prevent reabsorption of sodium in the loop of Henle. Thiazide diuretics prevent sodium from being reabsorbed at the beginning of the distal convoluted tubules. Potassium-sparing diuretics stop the extensive loss of potassium at the distal convoluted tubules. Excessive use to treat certain conditions requires careful monitoring and frequent lab testing of the electrolytes.
Antispasmodics
Anticholinergics are often used to relieve smooth muscle spasms in the bowel or bladder. Bladder spasms can occur as a consequence of neurologic injury. Anticholinergics can reduce bladder spasms and can provide relief from urinary incontinence. Bowel spasms commonly occur with irritable bowel syndrome. Some antispasmodic medications, such as Imodium (loperamide), are effective for the treatment of diarrhea because they cause a reduction in peristalsis and slow the passage of stool.
Agents to manage constipation
Pharmacologic management to treat stool retention includes both prescribed and over-the-counter versions of laxatives, bulk-forming agents, bowel stimulants, lubricants, stool softeners, saline laxatives, and enemas. The drawback in using these medications is that the bowel can become dependent on laxatives and stimulants for the impulse to defecate. Medications for stool retention should be a last resort and discontinued as soon as the bowel elimination is achieved.
Analgesics
Analgesics are indicated for relief of mild discomfort to severe pain for select urinary or bowel elimination conditions. Examples of conditions causing pain with elimination include kidney stones, cystitis, UTIs, bladder spams, hemorrhoids, and rectal fissures.
Incontinence Management
Multidisciplinary management of the person with alterations in elimination must occur to successfully control the condition. The need for retraining the bowel and bladder is of paramount importance. Providing a regular toileting schedule, managing fluid intake, modifying the environment, avoiding indwelling catheters, providing high-quality skin care and assessment, and avoiding medications that contribute to incontinence are nursing actions that will promote urinary continence. The use of an external urinary collection (EUC) device such as PureWick, is a noninvasive approach for managing female incontinence.22 Personal absorbent pads or bed-protecting pads may be used to catch episodes of incontinence in both mobile and immobile individuals. Biofeedback may be used to assist the person in gaining improved control over the muscles of elimination. Biofeedback involves placement of sensors onto the affected area of bowel so that the person can receive feedback regarding which muscles are being used to control bowel function. Among those with dementia, toilet assistance (including timed voiding and prompted voiding) along with protective pads and skin care are standard interventions.23
Invasive Procedures and Surgical Interventions Involving Urinary Elimination
A variety of procedures are performed as treatment for urinary elimination problems. The benefits must outweigh the risks for utilization of these interventions because they can be invasive and sometimes lifestyle-altering procedures.
Dialysis
Dialysis is indicated for acute or chronic renal failure. It involves filtration of the blood to remove toxins through an external process. Two types of dialysis are hemodialysis and peritoneal dialysis. A dialysis machine is used in hemodialysis to filter a patient’s blood to remove excess toxins and water. The blood is circulated from the patient to the dialysis machine and then back to the patient over several hours. In peritoneal dialysis, a dialysate solution is introduced into the peritoneal cavity that absorbs the toxins over several hours; the solution and waste are then removed.
Procedures relieving urinary retention
The most common procedure to relieve urinary retention is urinary catheterization.24 This can be intermittently performed with a straight catheter, or an indwelling catheter can be inserted. Measures must be taken to prevent complications (e.g., infection) when urinary drainage systems are used for long periods of time.25
Surgical intervention may be needed to treat other forms of obstructions, including surgery on the bladder, prostate, or ureters. Many procedures are conducted through a cystoscope. Stents, which are rigid tubes that provide an opening that is not normally present, may be used internally in the urethra and externally as part of anastomosis procedures performed for bladder cancer. Stents maintain the patency of pathways for urinary elimination.
Removing renal calculi
Renal calculi (also known as kidney stones) often require surgical intervention if the stones are unable to pass through the urinary tract. A variety of surgical procedures are available to treat renal calculi, including lithotripsy (fragmentation of the stones through sound wave technology); endourologic procedures (insertion of a ureteroscope and crushing the stones with a surgical instrument called a lithotrite); or open procedures (nephrolithotomy, pyelolithotomy, ureterolithotomy, or cystotomy), in which an incision is made and the stone is surgically removed.
Nephrectomy
Occasionally, surgical removal of the kidney is required, as with renal cancer. Other conditions, such as polycystic kidney disease, may also require surgical intervention.
Prostate surgery
An enlarged prostate can cause significant urinary obstruction. A transurethral resection of the prostate is a surgical procedure done for benign prostate hypertrophy when other noninvasive treatment measures have failed. Prostatectomy refers to the removal of the prostate and is usually performed among younger men diagnosed with prostate cancer, particularly if diagnosed in early disease stage.
Bladder surgeries
Surgical interventions of the bladder include a wide variety of procedures to treat many types of conditions, such as prolapsed bladder or bladder cancer. Surgical treatment options include laser surgery, transurethral resection, and partial or total cystectomy. If the bladder is removed, urinary diversion is required.
Urinary diversion
Urinary diversion procedures involve diverting the ureters to a urinary stoma on the skin (usually on the abdomen). There are multiple types of diversion procedures that are described in greater detail in many nursing textbooks. Urinary diversion is required with a cystectomy and is also used in the treatment of other conditions, such as bladder cancer, neurogenic bladder, or trauma to the bladder. Maintenance of skin integrity at the stoma site is of great importance. External urinary pouches are used in many cases to collect urine in these types of situations.
Invasive Procedures and Surgical Interventions Involving Bowel Elimination
Surgical procedures for bowel elimination problems are primarily associated with the colon, rectum, and anus, and they treat pathologic conditions or traumatic injury.
Colectomy
A colectomy (also referred to as a colon resection) involves removing a portion of the bowel. This may be done because of disease to a portion of the bowel (e.g., a cancerous tumor) or as treatment for traumatic injury. The two ends of the remaining colon are reattached (anastomosed).
Colostomy/ileostomy
Diversion of the intestines (colon or small intestine) through a stoma on the skin is occasionally needed temporarily or permanently as a result of injured or diseased intestine, colon, or rectum. The use of external devices (e.g., a colostomy pouch) is required for the collection of stool. Maintenance of skin integrity around the stoma is of utmost importance.23
Rectal prolapse repair
Rectal prolapse is a condition that occurs when the rectum falls into or through the anal opening. This is most common among young children and the elderly. Prolapse can occur from weak pelvic floor muscles or from excessive straining during bowel movements, as with chronic constipation. Surgical repair is indicated if prolapse occurs regularly or is associated with significant discomfort.
Hemorrhoidectomy
This procedure involves the excision of internal or external hemorrhoids. Hemorrhoids may require surgical intervention if topical treatments and changes in diet do not eliminate their associated discomfort. Thus, this procedure is usually only performed for patients with severe pain and multiple thrombosed hemorrhoids or when there is significant prolapse.
Fecal collection systems
A fecal collection system uses a flexible tube inserted into the rectum that is used to collect liquid stool in patients with incontinence who are not candidates for bowel retraining or have Clostridium difficile and its resulting diarrhea. These are fecal management systems for liquid stool only and help prevent skin breakdown in cases of severe diarrhea.
INTERRELATED CONCEPTS
A number of interrelated concepts presented in this text are associated with elimination (Fig. 15.5). Nutrition has a close interrelationship with bowel and urinary elimination. The types of foods and fluids ingested affect stool formation and urinary elimination. The kidneys play a vital role in maintaining homeostasis of Fluid and Electrolytes and Acid–Base Balance. Under the direction of hormones, the kidneys retain or eliminate water and electrolytes, which are critical for these balances to be maintained. Also, changes in electrolyte balance can influence neuromuscular transmission of smooth muscles, thus reducing or increasing intestinal peristalsis.
A lack of Mobility can result in both urinary and bowel elimination problems. Mobility helps with stimulation of peristalsis. Immobility, particularly when an individual is in a supine position, can lead to ineffective bladder emptying. Finally, changes in Cognition increase the potential for complications in both elimination mechanisms and can result from the inability to obtain and maintain adequate food and fluid intake. They can also lead to an inability to recognize cues for elimination—thus leading to incontinence.
CLINICAL EXEMPLARS
Exemplars of alterations in urinary elimination include conditions across the lifespan—ranging from bed-wetting, which may occur as a child is learning to control urinary elimination, to incontinence, which may occur as a person ages and the muscles supporting the bladder become less efficient. Bowel function also spans the life cycle; a variety of issues may affect function as an infant, such as structural problems in the bowel (e.g., strictures and fissures), whereas functional issues such as constipation may occur with advanced age. Box 15.1 presents common exemplars of conditions associated with the Concept of Elimination. Some of the most common exemplars of impaired elimination, urinary, and fecal incontinence have previously been described in the variations and context section of this concept presentation.
Featured Exemplars
Urolithiasis
Urolithiasis refers to the presence of stones called calculi within the urinary tract. Although it is not entirely clear how stones are formed, most contain calcium. Stones can form in the kidney (nephrolithiasis) or within the ureters (ureterolithiasis). The stones are associated with severe pain when they move down the ureter, into the bladder, and through the urethra (referred to as “passing the stone”).23 Hematuria is a common finding. If the stone becomes lodged in the ureter, a blockage can occur, leading to hydronephrosis and impaired kidney function.
FIG. 15.5 Elimination and Interrelated Concepts.
BOX 15.1 Exemplars of Impaired Elimination
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Incontinence
• Bed-wetting
• Stress incontinence
• Urge incontinence
• Fecal incontinence
Retention
• Benign prostatic hyperplasia
• Bladder cancer
• Bowel obstruction
• Colorectal cancer
• Constipation
• Fecal impaction
• Prostatitis
• Prostate cancer
• Spinal cord injury
• Urethral stricture
Discomfort
• Anal fissure
• Anorectal abscess
• Hemorrhoids
• Interstitial cystitis
• Pilonidal cyst
• Urolithiasis
Infections and Inflammation
• Crohn’s disease
• Diarrhea
• Gastritis
• Gastroenteritis
• Glomerulonephritis
• Pyelonephritis
• Ulcerative colitis
• Urinary tract infection
Renal Failure
• Acute kidney injury
• Chronic kidney disease
Neoplasms
• Benign prostatic hyperplasia
• Bladder cancer
• Colorectal cancer
• Prostate cancer
• Renal cancer
Benign Prostatic Hyperplasia
Benign prostatic hyperplasia is an enlargement of the prostate gland commonly seen among older men. It is estimated that 30% of men age 60 years have moderate symptoms and 50% of men age 80 years or older have symptoms.26 If untreated, the enlarging prostate, which surrounds the urethra at the base of the bladder, can obstruct urine flow, creating urinary retention. Common symptoms include frequency of urination, increased frequency of urinating at night, difficulty starting urinary flow, and a weak urinary stream. Chronic retention of urine can lead to UTI.
Urinary Tract Infection
UTI is caused by an infection in the urinary tract, representing the second most common bacterial infection in individuals. The symptoms associated with UTI include nausea and vomiting, chills, suprapubic or low back pain, bladder spasms, dysuria, burning with urination, frequency, urgency, hesitancy, or nocturia. UTIs are seen more frequently in pregnant women, females, and older men and women. These infections may cause sepsis and can result in death if not treated, especially in the elderly.23
Renal Failure
Renal failure occurs when there is a partially or complete cessation of kidney function. Renal failure can be acute or chronic. AKI is associated with a loss of renal function over a few days and can typically be reversed. CKD involves a process of renal failure that occurs over a long period of time. It is characterized by a gradual decrease in renal functioning and a gradual increase in metabolic waste. Regardless of the cause, untreated renal failure results in fluid overload, electrolyte imbalances, and metabolic acidosis, and ultimately leads to death.
Constipation
Constipation refers to difficulty passing stool and is usually associated with the passage of hard, dry stool; it can occur among individuals of any age. Constipation may be painful due to the bloating and flatus that may occur and also with trying to pass the stool itself. Chronic constipation may be caused by a lack of dietary fiber, certain medications (narcotic pain medications), chronic decreased intestinal peristalsis, or decreased fluid intake.23
Diarrhea
Diarrhea is the frequent passing of watery, liquid, or loose stools and occurs among individuals across the lifespan. It can be acute or chronic. Acute diarrhea is usually associated with inflammation within the gastrointestinal tract due to a virus or bacteria and usually resolves in a few days. Chronic diarrhea persists for a longer period of time, such as several weeks. Because diarrhea is associated with the loss of water and electrolytes, dehydration and electrolyte imbalance may occur quickly, particularly among infants, children, and older adults.23
Colorectal Cancer
Colorectal cancer is the third leading cause of cancer in men and women in the United States, and caused an estimated 52,550 deaths in 2023.27 Colorectal incidence and mortality rates are highest among African American men and women. Colorectal screening can prevent the development of cancer by removing precancerous colon polyps and has been credited with reducing the incidence and mortality during the past decade.
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CASE STUDY
Case Presentation
Ms. Amanda Doyle is a 67-year-old White female with a history of type 1 diabetes and osteoarthritis in her left hip. Her diabetes is well controlled with diet and insulin. Although she takes ibuprofen to treat the arthritic pain, her mobility has declined, and she now uses a walker. Because of a past bad experience with anesthesia, she has been resistant to having hip replacement surgery and instead opted to increase the dosage of ibuprofen to 600 mg four times a day and just learn to live with the pain.
For the past 3 months, Ms. Doyle has experienced intermittent abdominal pain, cramping, and bloating with diarrhea. She also has had a reduced appetite and has frequently felt tired.
On several occasions she has experienced fecal incontinence because she was unable to get to the bathroom in time and was unable to “hold it.” On two occasions, she experienced fecal incontinence in a public setting and was completely embarrassed by the situation. She is now afraid to leave the house because she fears it will happen again.
Ms. Doyle’s daughter took her to her primary care provider who ordered several diagnostic tests. An occult blood test showed blood in her stool. A stool culture was done to rule out parasitic infections; this was negative. Because it had been 9 years since her last colonoscopy, a colonoscopy was ordered to rule out pathology within the colon such as ulcerations, inflammation, or tumors. The colonoscopy revealed inflammation to the lining of her colon. Her physician made the diagnosis of inflammatory bowel disease.
Case Analysis
1. In what way does the case exemplify the Concept of Elimination?
2. What risk factors for altered elimination (fecal incontinence) and inflammatory bowel disease does Ms. Doyle have?
3. How are the diagnostic tests described in the case consistent with what was described for assessment of elimination?