Urinary elimination is the last step in the removal and elimination of excess water and byproducts of body metabolism. Adequate elimination depends on the coordinated function of the kidneys, ureters, bladder, and urethra. The kidneys filter waste products of metabolism from the blood. The ureters transport urine from the kidneys to the bladder. The bladder holds urine until the volume in the bladder triggers a sensation of urge indicating the need to pass urine. Micturition occurs when the brain gives the bladder permission to empty, the bladder contracts, the urinary sphincter relaxes and urine leaves the body through the urethra.
The kidneys lie on either side of the vertebral column behind the peritoneum and against the deep muscles of the back. Normally the left kidney is higher than the right because of the anatomical position of the liver.
Nephrons, the functional unit of the kidneys, remove waste products from the blood and play a major role in the regulation of fluid and electrolyte balance. The normal range of urine production is 1 to 2 L/day. Erythropoietin, produced by the kidneys, stimulates red blood cell (RBC) production and maturation in bone marrow. The kidneys play a major role in blood pressure control via the renin-angiotensin system, release of aldosterone and prostacyclin. The kidneys also affect calcium and phosphate regulation by producing a substance that converts vitamin D into its active form.
A ureter is attached to each kidney pelvis and carries urinary wastes to the bladder.
The urinary bladder is a hollow, distensible, muscular organ that holds urine. The bladder has two portions, a fixed base called the trigone and a distensible body called the detrusor. The bladder expands as it fills with urine.
Urine travels from the bladder through the urethra and passes to the outside of the body through the urethral meatus. The urethra passes through a thick layer of skeletal muscles called the pelvic floor muscles. These muscles stabilize the urethra and contribute to urinary continence. The external urethral sphincter, made up of striated muscles, contributes to voluntary control over the flow of urine. The female urethra is approximately 3 to 4 cm (1 to 1.5 in) long and the male urethra is about 18 to 20 cm (7 to 8 in) long. The shorter length of the female urethra increases risk for urinary tract infection due to close access to the bacteria contaminated perineal area.

The Bowman’s capsule (renal capsule):
surrounds a ball of capillaries called the capillary knot
high pressure is created in the capillary knot by the diameter of the capillary leaving the knot being narrower than the capillary entering
this pressure results in ultrafiltration where water, salts, glucose, and other small molecules pass out of the capillary and into the Bowman's capsule
proteins and blood cells are too big to leave the capillaries to go into the tubule
The rest of the tubule is responsible for the selective reabsorption of glucose, some salts, and lots of the water.
The collecting duct is responsible for the selective reabsorption of water and for sending urine to the ureter.

Urination, micturition, and voiding are all terms that describe the process of bladder emptying. Micturition is a complex interaction between the bladder, urinary sphincter, and central nervous system.
Several areas in the brain are involved in bladder control; cerebral cortex, thalamus, hypothalamus and brainstem. There are two micturition centers in the spinal cord; one that coordinates inhibition of bladder contraction and the other that coordinates bladder contractility.
As the bladder fills and stretches, bladder contractions are inhibited by sympathetic stimulation from the thoracic micturition center.
When the bladder fills to approximately 400 to 600mL, most people experience a strong sensation of urgency.
When in the appropriate place to void, the central nervous system sends a message to the micturition centers, stopping sympathetic stimulation and starting parasympathetic stimulation from the sacral micturition center. The urinary sphincter relaxes and the bladder contracts.
When the time and place is inappropriate, the brain sends messages to the micturition centers to contract the urinary sphincter and relax the bladder muscle.

Babies and young children do not concentrate urine efficiently and are prone to F&E imbalances.

Children cannot voluntarily control voiding until 18 to 24 months.
Readiness for toilet training includes the ability to: recognize the feeling of bladder fullness, to hold urine for 1 to 2 hours, and communicate the sense of urgency.

Nocturnal enuresis -
Inappropriate voiding at least once a month for 3 consecutive months after age 5, not related to medical condition of effect of medication
more common in boys with strong familial tendency
usually stops between 6 and 8
Multiple treatment methods: medication, restriction of fluids after dinner, avoidance of caffeine and sugar after 4 pm, purposeful interruption of sleep, avoiding constipation, bedwetting alarm

Older adults may experience a decrease in bladder capacity, increased bladder irritability and an increased frequency of bladder contractions during bladder filling.
In older adults, the ability to hold urine between the initial desire to void and an urgent need to void decreases.
Older adults are at increased risk for urinary incontinence due to chronic illnesses and factors that interfere with mobility, cognition, and manual dexterity.

If fluids, electrolytes, and solutes are balanced, increased fluid intake increases urine production.
Alcohol decreases the release of antidiuretic hormones, thus increasing urine production.
Fluids containing caffeine and other bladder irritants can prompt unsolicited bladder contractions resulting in frequency, urgency, and incontinence.

Cultural and gender norms vary. North Americans expect toilet facilities to be private, whereas some cultures accept communal toilet facilities.
Religious or cultural norms may dictate who is acceptable to assist in elimination practices.
Social expectations (e.g., school recesses, work breaks) can interfere with timely voiding.
Anxiety and stress sometimes affect a sense of urgency and increase the frequency of voiding.
Anxiety can impact bladder emptying due to inadequate relaxation of the pelvic floor muscles and urinary sphincter.
Depression can decrease the desire for urinary continence.
The need for privacy and adequate time to void can influence the ability to adequately empty the bladder.

Diuretics increase urinary output by preventing reabsorption of water and certain electrolytes.
Some drugs change the color of urine (e.g., phenazopyridine - orange, riboflavin - intense yellow).
Aniticholinergics (e.g., atropine, OAB agents) may increase the risk for urinary retention by inhibiting bladder contractility
Hypnotics and sedatives (e.g., analgesics, antianxiety agents) may reduce the ability to recognize and act upon the urge to void.

Diabetes mellitus, multiple sclerosis, and stoke can alter bladder contractility in addition to the ability to sense bladder filling. Patients will experience either bladder overactivity or deficient bladder emptying.
Arthritis, Parkinson’s disease, dementia, and chronic pain syndromes can interfere with timely access to a toilet.
Spinal cord injury or intervertebral disk disease (above S-1) can cause the loss of urine control due to bladder overactivity and impaired coordination between the contracting bladder and urinary sphincter.
Prostatic enlargement (e.g., benign prostatic hyperplasia or BPH) can cause obstruction of the bladder outlet causing urinary retention.
Local trauma during lower abdominal and pelvic surgery sometimes obstructs urine flow requiring temporary use of an indwelling urinary catheter.
Cystoscopy may cause localized trauma of the urethra resulting in transient (1 to 2 days) dysuria and hematuria.
Whenever the sterile urinary tract is catheterized, there is a risk for infection.

A physical examination provides you with data to determine the presence and severity of urinary elimination problems. The primary areas to assess include the kidneys, bladder, external genitalia, urethral meatus, and perineal skin. Fluid intake and the pattern and amounts, which are objective data, are important to assess.
You assess for kidney tenderness by gently percussing the costovertebral angle (the angle formed by the spine and twelfth rib). Auscultation is sometimes performed to detect the presence of a renal artery bruit (sound resulting from turbulent blood flow through a narrowed artery).
Percussion is an excellent technique to identify a full bladder. Gently tap the abdomen along the midline starting just above the umbilicus. The edge of the bladder is identified when the percussion note changes to a dull note. If an overfull bladder is suspected, further assessment using a bladder scanner is recommended if available.
Careful and sensitive inspection of the external genitalia and urethral meatus yield important data that may indicate inflammation and infection. Look for discharge, lesions, or inflammation. All patients with an indwelling catheter should have the urinary meatus assessed for catheter-related damage, and for the presence of inflammation and discharge that can indicate infection.
Assessment of skin exposed to moisture, especially urine, needs to occur on a regular basis in order to pick up early signs of skin damage related to the moisture.

The assessment of urine includes measuring the patient’s fluid intake and urinary output (I&O), and observing the characteristics of the urine.
Assessment of I&O is a way to evaluate bladder emptying, renal function, and fluid and electrolyte balance. Intake measurements need to include all oral liquids and semi-liquids, enteral feedings, and any parenteral fluids. Output measurement includes not only urine but any fluid that leaves the body that can be measured, such as vomitus, gastric drainage tubes, and wound drains. A change in urine volume can be a significant indicator of fluid imbalance, kidney dysfunction, or decreased blood volume. After a patient voids in a bedside commode, bedpan, or urinal, or when urine is emptied from a catheter drainage bag, urine can be measured using a graduated measuring container. For patients who void in a toilet, a urine hat will collect urine, allowing for patient privacy in the bathroom. Catheterized patients may have a specialized drainage bag with an urometer attached between the drainage tubing and drainage bag that allows for accurate hourly urine measurement. Each patient needs to have a graduated receptacle for individual use to prevent potential cross-contamination.
​Inspect the patient’s urine for color, clarity, and odor. Monitor and document any changes.

Random (routine urinalysis)

Includes a number of tests that are used for screening and are diagnostic for fluid and electrolyte disturbances, urinary tract infection, presence of blood and other metabolic problems

Collect during normal voiding or from an indwelling catheter or urinary diversion collection bag.

Do not collect from an indwelling catheter drainage bag (urine is not freshly voided).

Use a clean specimen cup.

In some health care settings you may be responsible for testing urine with reagent strips. Follow manufacturer instructions when performing and reading the strips. Dip the reagent strip into fresh urine, then observe color changes on the strip. Compare the color on the strip with the color chart on the reagent strip container. Each color is examined at the exact time indicated on the container.

Clean-voided or midstream (culture and sensitivity)
Urine may be collected by the patient after detailed instruction on proper cleansing and collection technique (see Skill 46-1 on pp. 1128-1131).

Always use a sterile specimen cup.

Sterile specimen for culture and sensitivity

Determines the presence of bacteria and to which antibiotic the bacteria are sensitive

If the patient has an indwelling catheter, collect a specimen by using sterile aseptic technique through the special sampling port (see Figure 46-12) found on the side of the catheter. Never collect the specimen from the drainage bag.

Clamp the tubing below the port, allowing fresh, uncontaminated urine to collect in the tube. After wiping the port with an antimicrobial swab, insert a sterile syringe hub and withdraw at least 3 to 5 mL of urine (check agency policy).

Using sterile aseptic technique, transfer the urine to a sterile container (see Chapter 28).

Patients with a urinary diversion need to have the stoma catheterized to obtain an accurate specimen.

A preliminary report will be available in 24 hours; but usually 48 to 72 hours are needed for bacterial growth and sensitivity testing.

Timed urine specimens

Measure bodily substances that may be excreted at higher levels at specific times of the day or over a specific time period

Requires urine collection and testing either at specific time of day or urine collected over a specific time period (e.g., 2-, 12-, or 24-hour collections).

The timed period begins after the patient urinates and ends with a final voiding at the end of the time period. In most 24-hour specimen collections discard the first voided specimen and then start collecting urine.

Patient voids into a clean receptacle; and the urine is transferred to the special collection container, which often contains special preservatives.

Depending on the test, the urine container may need to be kept cool by setting it in a container of ice.

Each specimen must be free of feces and toilet tissue.

Missed specimens make the whole collection inaccurate. Check with agency policy and the laboratory for specific instructions.

Patients' education should include an explanation of the test, an emphasis on the need to collect all urine voided during the prescribed time period, and urine collection procedure.

Normal urine ranges in color from a pale straw color to amber, depending on its concentration. Bleeding from the kidneys or ureters usually causes urine to become dark red; bleeding from the bladder or urethra usually causes bright red urine. Various medications and foods change the urine’s color. Dark amber urine is the result of high concentrations of bilirubin (urobilinogen) in patients with liver disease. Report unexpected color changes to the health care provider.
Normal urine appears transparent at the time of voiding. Urine that stands several minutes in a container becomes cloudy. In patients with renal disease, freshly voided urine appears cloudy because of protein concentration. Urine may also appear thick and cloudy as a result of bacteria and white blood cells (WBCs).
Urine has a characteristic ammonia odor. The more concentrated the urine, the stronger the odor. As urine remains standing (e.g., in a collection device), more ammonia breakdown occurs and the odor becomes stronger. A foul odor may indicate a UTI. Some foods, such as asparagus and garlic, can change the odor of urine.

Specific gravity is a measurement of urine concentration and is representative of the kidney’s ability to concentrate urine. The specific gravity is a comparison of the amount of solutes in urine as compared with pure water.

Often specific gravity is reflective of hydration status; however, it can be inaccurate. Low specific gravity is seen in patients with impaired urinary concentrating ability (eg, diabetes insipidus, sickle cell nephropathy, acute tubular necrosis)

In most individuals, urine pH is usually lower, representing a slightly acidic environment. Therefore, any abnormalities in the acid-base balance in the body has a direct effect on urinary pH levels. Diet can also affect urinary pH levels. Cranberries and high-protein diets create a more acidic urinary environment, whereas citrus fruits and low-carbohydrate diets create a more alkaline urine environment.

Protein is normally not present in urine. The presence of protein is a very sensitive indicator of kidney function. Damage to the glomerular membrane (such as in glomerulonephritis) allows for the filtration of larger molecules such as protein to seep through.

Glucose present in the urine is termed glucosuria. Most commonly, this indicates diabetes mellitus but is also often seen in pregnancy. It is due to either a high blood glucose level or a decreased kidney threshold concentration. When blood glucose levels exceed approximately 180 mg/dL, the proximal tubules become overwhelmed and cannot reabsorb the excess glucose. As a result, glucose is then excreted in the urine.

Ketones in the urine are abnormal. Ketones accumulate when carbohydrates are insufficient and the body must get its energy from fat metabolism. Ketonuria may be seen with uncontrolled diabetes, diabetic ketoacidosis, severe exercise, starvation, vomiting and pregnancy.

Nitrite testing is sensitive, but not specific, in detecting UTIs. Normally no nitrites are detected in the urine. Urinary nitrates are converted to nitrites by bacteria in the urine. A positive nitrite result signifies that bacteria capable of this conversion (eg, Escherichia coli, Klebsiella, Proteus, Enterobacter, Citrobacter, Pseudomonas) are present in the urinary tract.

Bilirubin should not be present in the urine. In obstructive hepatobiliary conditions and in certain liver diseases, such as hepatitis, conjugated (water-soluble) bilirubin is excreted in the urine

WBCs contain an enzyme known as leukocyte esterase, which is released when WBCs undergo lysis. Normally, too few WBCs are present in the urine for the test to be positive. However, when the number of WBCs in the urine increases, the result becomes positive. [1] A positive leukocyte esterase test result indicates pyuria.

WBC - Elevated numbers indicate inflammation or infection.

A positive test for occult blood occurs when intact erythrocytes, hemoglobin, or myoglobin is present. Damage to the glomerulus or tubules causes blood cells to enter urine. Trauma or disease of the lower urinary tract also causes hematuria.

Bacteria/Yeast -Bacteria in the urine can mean infection or colonization (if no symptoms)

Casts - (cylindrical bodies not normally present, the shapes of which take on the likeness of objects within the renal tubule). Types include hyaline, WBCs, RBCs, granular cells, and epithelial cells. Their presence indicates renal disease.

Crystals indicate increased risk for the development of renal calculi (stone). Patients with high uric acid levels (gout) may develop uric acid crystals.

Nursing responsibilities before testing:
Ensure a signed consent is completed.
Assess the patient for any allergies.
Administer bowel-cleansing agents as ordered.
Ensure that the patient adheres to the appropriate pretest diet or nothing by mouth (NPO).
Responsibilities after testing include:
Assessing I&O
Assessing voiding and urine
Encouraging fluid intake

The most common urinary elimination problems involve the inability to store urine or to fully empty urine from the bladder. Problems can result from infection, irritable or overactive bladder, obstruction of urine flow, impaired bladder contractility, or issues that impair innervation to the bladder resulting in sensory or motor dysfunction.
Patients may have no urine output over several hours, and in some cases will experience frequency, urgency, small volume voiding or incontinence of small volumes of urine. Postvoid residual (PVR) is the amount of urine left in the bladder after voiding and is measured either by ultrasound or straight catheterization. Incontinence caused by urinary retention is called overflow incontinence or incontinence associated with chronic retention of urine. The pressure in the bladder exceeds the ability of the sphincter to prevent the passage of urine and the patient will dribble urine.
[Review Table 46-1, Urinary Incontinence, with students.]
Urinary tract infections (UTIs) are usually caused by Escherichia coli. Urinary tract infections are characterized by location; upper urinary tract (kidney) or lower urinary tract (bladder, urethra) and have signs and symptoms of infection. Bacteriuria, or bacteria in the urine, does not always mean that there is an infection. Symptomatic infection of the bladder should be treated with antibiotics and can lead to a serious upper urinary tract infection (pyelonephritis) and life-threatening blood stream infection (bacteremia or urosepsis). Symptoms of a lower urinary tract infection (bladder) can include: burning or pain with urination (dysuria), irritation of the bladder (cystitis) characterized by urgency, frequency, incontinence, suprapubic tenderness, and foul-smelling cloudy urine. Catheter-associated UTIs (CAUTIs) are associated with increased hospitalizations, increased morbidity and mortality, longer hospital stays, and increased hospital costs. Because a CAUTI is common, costly, and believed to be reasonably preventable, as of October 1, 2008, the Centers for Medicare and Medicaid Services (CMS) chose it as one of the complications for which hospitals no longer receive additional payment to compensate for the extra cost of treatment. Consequently, there has been a shift in reimbursement practices from its traditional focus on early recognition and prompt treatment to one of prevention.
Common forms of UI are urge or urgency UI (involuntary leakage associated with urgency) and stress UI (involuntary loss of urine associated with effort or exertion, on sneezing or coughing. Mixed UI is when stress and urgency type symptoms are both present. Overactive bladder is defined as urinary urgency, often accompanied by increased urinary frequency and nocturia that may or may not be associated with urgency incontinence and is present without obvious bladder pathology or infection. Urinary incontinence associated with chronic retention of urine (formally called Overflow UI) is urine leakage caused by an overfull bladder. Functional UI is caused by factors that prohibit or interfere with a patient’s access to the toilet or other acceptable receptacle for urine. In most cases, there is no bladder pathology. It is a significant problem for older adults who experience problems with mobility or the dexterity to manage their clothing and toileting behaviors. A recently added category of incontinence is identified as Multifactorial incontinence. This describes incontinence that has multiple interacting risk factors, some within the urinary tract and others not, such as multiple chronic illnesses, medications, age-related factors, and environmental factors.

Tolterodine tartrate
Use
Control an overactive bladder
Decrease urge and urinary incontinence
Side effects/adverse reactions
Headache, dizziness, confusion
Blurred vision, dysphonia
Peripheral edema, elevated hepatic enzymes
Dry mouth, diarrhea, constipation, abdominal pain
Contraindications
Narrow-angle glaucoma
Hepatic impairment

Oxybutynin
Action
Direct action on smooth muscles to relieve spasms
Side effects/adverse reactions
Drowsiness, dizziness
Blurred vision, tachycardia
Dry mouth, GI distress, constipation
Contraindication
Avoid in glaucoma, GI, or urinary obstruction

Bethanechol
Action
Increase bladder tone of detrusor muscle
Use
Neurogenic bladder, urinary retention
Side effects/adverse reactions
GI distress, headache, dizziness
Nephrotoxicity, hepatotoxicity
Contraindication
Peptic ulcer


Phenazopyridine
Action
Relieve pain, burning sensation, frequency, urgency
Side effects/adverse reactions
GI distress
Red-orange urine
Hemolytic anemia
Nephrotoxicity, hepatotoxicity

Fluoroquinolones
Use
Treats lower UTIs
Side effects/adverse reactions
Headache, dizziness
Photosensitivity, visual impairment
Peripheral neuropathy, GI distress
Tendinitis, tendon rupture, seizures
Clostridium difficile–associated diarrhea
Caution
Use in uncomplicated UTI only if no other treatment options are available

Nitrofurantoin
Bacteriostatic or bactericidal
Depending on the drug dosage
Effective against many gram-positive and gram-negative organisms, especially E. coli.
Side effects/adverse reactions
Anorexia, nausea, vomiting, abdominal pain, diarrhea
Clostridium difficile–associated diarrhea
Peripheral neuropathy, brown urine discoloration
Monitor urinary output and urine specific gravity.
Obtain urine culture to identify infecting organism before initiation of drug therapy to treat UTI.
Advise patient to avoid antacids as they interfere with absorption.
Inform patient to increase fluids and take the drug with food to minimize GI upset.

Patients who have had the bladder removed (cystectomy) due to cancer or significant bladder dysfunction related to radiation injury or neurogenic dysfunction with frequent UTI, require surgical procedures that divert urine to the outside of the body through an opening in the abdominal wall called a stoma. Urinary diversions are constructed from a section of intestine to create a storage reservoir or conduit for urine. Diversions can be temporary or permanent, continent or incontinent.
There are two types of continent urinary diversions. The first is called a continent urinary reservoir, which is created from a distal portion of the ileum and proximal portion of the colon. The second type of continent urinary diversion is called an orthotopic neobladder, which uses an ileal pouch to replace the bladder. A ureterostomy or ileal conduit is a permanent incontinent urinary diversion created by transplanting the ureters into a closed-off portion of the intestinal ileum and bringing the other end out onto the abdominal wall forming a stoma. The patient has no sensation or control over the continuous flow of urine through the ileal conduit requiring the effluent (drainage) to be collected in a pouch.