Urinary Elimination

Urinary Elimination 1. Anatomy of the urinary tract a. divided into four parts: i. kidneys a. two reddish-brown, bean-shaped organs located on either side of the vertebral column behind the abdominal peritoneum and against the deep muscles of the back

b. each kidney has its own blood supply 1. one renal artery a. originates in the abdominal aorta b. enters the kidney at the hilum 2. one renal vein a. exits the kidney through the hilum b. joins the inferior vena cava c. each kidney has over 1,000,000 nephrons, its functional unit that filters waste products from the blood and regulates fluid and electrolyte concentrations in the body fluids, which are composed of six parts 1. glomerulus 2. Bowman’s capsule 3. proximal convoluted tubule 4. loop of Henle 5. distal convoluted tubule 6. collecting duct

ii. ureters a. two tubular structures attached to each kidney pelvis which carry urine from the kidneys into the bladder b. length of the ureters 1. 25 to 30 centimeters (10 to 12 inches) long c. a small, flaplike fold of mucous membrane covers the junction of the ureters and the bladder and acts as a valve to prevent urinary reflux (backflow) iii. bladder a. a hollow, distensible, muscular organ that is a reservoir for urine b. composed of three parts 1. detrusor muscle a. composed of three layers of smooth muscle i. inner; longitudinal ii. middle; circular iii. outer; longitudinal 2. the trigone (a triangle-shaped area located at the base of the bladder) a. the ureter openings at the posterior corners form the base of the triangle b. the opening of the urethra at the anterior inferior corner forms the apex of the triangle 3. internal urinary spinchter (involuntary control; sits at the base of the bladder) iv. urethra a. a tubular structure attached to the bladder that carries urine from the bladder to the urinary meatus and outside of the body b. length of the urethra 1. women: 3.7 centimeters (1.5 inches) long 2. men: 20 centimeters (8 inches) long a. consists of three parts i. prostatic ii. membranous iii. cavernous b. important in renal and reproductive functioning i. carries urine outside the body ii. carries semen outside the body c. external urinary spinchter (voluntary control) sits at the base of the urethra 2. Process of urine production a. glomerular filtration i. blood enters the glomerular capillaries and is filtered in the following ways: a. red blood cells and protein molecules are too big and cannot pass through the glomerular capillaries out of the glomerulus and into Bowman’s capsule and, consequently, stay in the bloodstream

b. all other constituents of the plasma pass through the glomerular capillaries out of the glomerulus and into Bowman’s capsule and, consequently, become what is known as the glomerular filtrate

ii. rate of formation of glomerular filtrate a. 25 milliliters a minute b. 180 liters daily b. tubular reabsorption i. as the glomerular filtrate passes through the tubules, substances that the body wants to retain are actively and passively reabsorbed, e.g.: a. water b. electrolytes (sodium, potassium, chloride, bicarbonate) c. glucose d. amino acids ii. about 99% of the glomerular filtrate is reabsorbed by the tubules iii. the remaining 1% of the glomerular filtrate that is not reabsorbed by the tubules forms the fluid waste called urine c. tubular secretion i. the tubules also secrete some substances into the glomerular filtrate to remove them from the body, e.g.: a. hydrogen ions b. potassium ions

c. ammonia d. creatinine e. uric acid 3. Process of urinary elimination (voiding; micturation) a. usually occurs when the volume of urine in the bladder reaches about 250 to 450 milliliters i. pressure of that amount of urine stimulates sensory nerve fibers in the detrusor muscle called stretch receptors ii. these stretch receptors transmit their sensory impulses through pelvic nerve fibers to the voiding reflex center located in the sacral 2 - 4 segments of the spinal cord

iii. these fibers then synapse through interneurons to the anterior portion of the spinal-cord at that level iv. motor impulses are then transmitted from the anterior root of the sacral 2 - 4 segments of the spinal cord through parasympathetic nerve fibers by way of the pelvic nerve back to the detrusor muscle causing it to contract and open the internal urinary spinchter

v. the individual perceives the need to void and finds a toilet vi. the individual inhbits the external urinary spinchter voluntarily through a similar reflex arc described above by way of pudendal nerve fibers vii. voiding occurs 4. Factors influencing urinary elimination a. age i. children a. desire to control daytime urinary elimination occurs when a child becomes aware of the following (usually around 2 years old): 1. discomfort of a wet diaper 2. sensation that indicates need for elimination of urine b. nurses can become involved in a child’s toilet training in the following ways: 1. continuing the toilet training program established at home while the child is in the hospital 2. educating parents on methods for successful toilet training, such as providing their child with the following: a. clothes that can be removed independently b. a personal toilet seat c. sufficient time to eliminate urine d. a consistent, relaxed atmosphere e. praise for successful behavior while avoiding punishment for unsuccessful behavior f. a non-stressful period in which to initiate toilet training ii. elderly a. changes in the elderly that can effect urinary elimination include the following: 1. 30 to 50% decrease in the number, size, weight, and function of the nephrons and, consequently, the size and weight of the kidney 2. decreased renal blood flow and, consequently, glomerular filtration rate 3. decreased reabsorptive and secretory capabilities of the renal tubules and, consequently, ability to concentrate urine 4. decreased muscle tone and contractility of the detrusor muscle and, consequently, ability to empty bladder without leaving residual urine and difficulty starting the urinary stream

5. decreased innervation of the detrusor muscle and external urinary spinchter and, consequently, ability to maintain urinary continence b. fluid intake i. intake of increased or decreased amounts of fluid can effect urinary elimination in the following ways: a. increased fluid intake increases urine production and elimination by inhibiting the release of anti-diuretic hormone (ADH) which inhibits reabsorption of water in the renal tubules

b. decreased fluid intake decreases urine production and elimination by facilitating the release of ADH which facilitates reabsorption of water in the renal tubules

ii. intake of certain types of fluids can adversely effect urinary elimination, such as the following: a. alcohol, caffeine 1. increase urine production and elimination by inhibiting the release of ADH which inhibits reabsorption of water into the renal tubules b. fluids containing sodium 1. decrease urine production and elimination by providing an increased amount of sodium in the glomerular filtrate which facilitates water, along with the sodium, to be reabsorbed by the renal tubules

c. food intake i. intake of certain foods can effect urinary elimination in the following ways: a. increase urine production and elimination if high in fluid content 1. e.g., fruits, vegetables, cooked cereal b. decrease urine production and elimination if high in sodium content 1. e.g., potato chips, cheese, pickles c. change the color of the urine 1. e.g., beets, blackberries may turn urine red 2. e.g., carrots (beta-carotene) may turn urine yellower than ususal d. medications i. certain medications can effect urinary elimination in the following ways, e.g.: a. cholinergics 1. stimulate contractions of the detrusor muscle which may facilitate urinary elimination, e.g.: a. bethanechol chloride (Urecholine) b. anticholinergics 1. inhibit contractions of the bladder and detrusor muscle which may lead to urinary retention, e.g.: a. atropine sulphate b. hyoscine c. homatropine methylbromide d. scopolamine e. hyoscyamine c. opioid analgesics 1. increase tone of the detrussor muscle and external urinary spinchter and suppress awareness of bladder distention which may lead to urinary retention, e.g.: a. morphine sulphate b. meperidine hydrochloride (Demerol) c. codeine d. hydromorphone (Dilaudid)

e. propoxyphene (Darvon) d. diuretics 1. increase urine production primarily by preventing reabsorption of sodium and, consequently, water in the renal tubules, e.g.: a. chlorothiazide (Diuril) b. hydrochlorothiazide (HydroDiuril) c. furosemide (Lasix) d. spironolactone (Aldactone) e. triamterene (Dyrenium) e. can change the color of the urine 1. to red, e.g.: a. methlydopa (Aldomet) 2. to orange, orange-red, or pink, e.g.: a. phenazopyridine (Pyridium) b. phenytoin (Dilantin) c. rifampin (Rifadin) d. warfarin sodium (Coumadin) 3. to green or blue-green, e.g.: a. amitriptyline (Elavil) b. indomethacin (Indocin) c. B-complex vitamins 4. to brown or black, e.g.: a. levodopa (L-Dopa) b. iron preparations, e.g.: i. ferrous sulphate (Feosal) ii. ferrous gluconate (Fergon) iii. ferrous fumarate (Feostat) e. activity i. inadequate activity can effect urinary elimination a. decreases the tone of the abdominal muscles which can result in a decreased amount of intra-abdominal pressure that can be exerted on the detrusor muscle during voiding

b. decreases the tone of the pelvic floor muscles which can result in a decreased ability of the external urinary spinchter to hold back the flow of urine when placed under pressure

f. psychologic factors i. certain emotional states can effect urinary elimination a. anxiety/stress activates the sympathetic portion of the autonomic nervous system (ANS) which inhibits detrusor muscle contractions and increases the tone of the internal urinary spinchter which can potentially lead to urinary retention

g. life-style i. certain life-style behaviors can effect urinary elimination by delaying voiding which can stretch and weaken the detrusor muscle and lead to incomplete

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empyting of the bladder, residual urine left in the bladder, and bladder infections such as the following: a. ingnoring the urge to void 1. insufficient time 2. unavailability of toilet facilities 3. lack of privacy b. inability to assume a normal position diagnostic procedures i. cystoscopy can effect urinary elimination in the following way: a. precipitate edema of the urethra which may obstruct the flow of urine and can result in urinary retention anesthesia and surgery i. general, spinal, and epidural anesthesia, and concomittant use of general and regional anesthetic agents, can effect urinary elimination in the following ways: a. decrease blood pressure, rate of glomerular filtration and, consequently, urine production and elimination b. effect innervation of the detrusor muscle and internal urinary spinchter which can result in urinary retention ii. surgery on any part of the urinary tract, intestines, and/or reproductive organs can effect urinary elimination by preciptitating the following: a. edema and/or bleeding which may obstruct the flow of urine and can result in urinary retention b. negative imbalance between intravenous fluid intake and fluid and blood loss which can result in decreased blood pressure, rate of glomerular filtration and, consequently, urine production and elimination c. release of ADH as part of the stress response pathologic conditions i. pathologic conditions can effect urinary elimination in the following ways: a. decrease or eliminate innervation of the detrusor msucle and internal and external urinary spinchters which can result in urinary incontinence, e.g.: 1. spinal-cord injury, cerebral vascular accident (CVA), multiple sclerosis b. decrease physical mobility and, consequently, ability to reach a toilet or bedside commode in time and/or assume a normal position for voiding, e.g.: 1. rheumatoid arthritis, degenerative joint disease, multiple sclerosis c. decrease the cognitive ability to consciously control voiding, e.g.: 1. CVA, Alzheimer’s disease, Parkinson’s disease d. alter the release of hormones that influence the production and elimination of urine, e.g.: 1. syndrome of inappropriate antidiuretic hormone (SIADH) a. results in the inappropriate release of ADH and decreased urine production and elimination 2. diabetes insipidus a. results in inhibition of the release of ADH and greatly increased urine production and elimination 3. aldosteronism a. results in excessive release of aldosterone (which facilitates reabsorption of sodium and, consequently, water from the renal tubules) and decreased urine production and elimination e. decrease the blood supply to the kidney, rate of glomerular filtration, and urine production and elimination, e.g.: 1. arteriosclerosis; shock; massive diarrhea, vomiting, and dehydration f. obstruct the flow of urine which can result in urinary retention, e.g.: 1. strictures of the ureters or urethra, benign prostatic hypertrophy, urinary tumors or other tumors that press against the urinary tract, urinary

calculi

g. alter the cellular structure and function of the kidney, e.g.: 1. polycystic kidney disease, acute glomerulonephritis, renal tuberculosis h. increase the core body temperature and basal metabolic rate which may result in sweating, insensible water loss, and decreased urine production

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and elimination, e.g.: 1. any significant infectious process, head injury, burns Common alterations in urinary production and elimination a. anuria i. voiding less than 100 milliliters in 24 hours b. oliguria i. voiding less than 500 milliliters in 24 hours c. polyuria i. producing abnormally large amounts of urine a. e.g., 2500 milliliters a day d. frequency i. voiding in frequent intervals e. nocturia i. voiding in frequent intervals at night f. urgency i. feeling of the need to void immediately a. may or may not pass a lot of urine g. dysuria i. painful or difficult voiding h. hesitancy i. difficulty in initiating voiding i. enuresis i. repeated involuntary urination in children beyond the age when voluntary bladder control is normally acquired a. primary 1. never has been a long, dry spell b. secondary (acquired) 1. occurs after a dry spell of at least a year c. nocturnal 1. occurs at night d. diurnal 1. occurs both day and night j. incontinence i. functional incontinence a. the state in which one experiences an involuntary, unpredictable passage of urine b. related factors (etiology) 1. altered environment 2. sensory, cognitive, or mobility deficits c. defining characteristics 1. inability to suppress detrusor muscle contractions until reaching an appropriate receptacle due to sensory, cognitive, or mobility deficits d. interventions 1. incontinence pads/pants during the day 2. clothes adapted for quick removal 3. provide means for summoning assistance 4. provide cues that mark the bathroom 5. remove obstacles to the bathroom 6. provide proper receptacle for urine 7. toilet every 3 hours 8. catheterize only if bladder training fails 9. perhaps an external catheter at night 10. limit use of coffee, tea, alcohol 11. encourage fluid intake of 1500-2000 milliliters a day 12. regulate fluid intake at prescheduled times to promote predictable voiding pattern 13. restrict fluids 2-3 hours before bedtime ii. reflex incontinence a. the state in which one experiences an involuntary passage of urine occurring at somewhat predictable intervals when a specific bladder volume is reached b. related factors (etiology) 1. spinal-cord injury above the reflex voiding center c. defining characteristics 1. uninhibited muscle contractions at somewhat predictable intervals when a specific bladder volume is reached d. interventions 1. clothes adapted for mobility problems 2. toilet day and night slightly before expected time of incontinence 3. attempt to stimulate the reflex voiding center prior to attempting to void (e.g., trigger voiding, straining to void, Crede’) 4. intermittent self-catheterization program 5. limit use of coffee, tea, alcohol 6. encourage fluid intake of 1500-2000 milliliters a day 7. regulate fluid intake at prescheduled times to promote predictable voiding pattern 8. restrict fluids 2-3 hours before bedtime iii. stress incontinence a. the state in which one experiences an involuntary passage of urine of less than 50 milliliters occurring with increased intra-abdominal pressure b. related factors (etiology) 1. degenerative changes in the pelvic muscles and structural supports associated with aging

2. high intra-abdominal pressure (e.g., obesity, gravid uterus) 3. incompetent bladder outlet 4. weak pelvic muscles and structural supports (e.g., multiple pregnancies) c. defining characteristics 1. dribbling of urine with increased intra-abdominal pressure (e.g., coughing, sneezing, straining) d. interventions 1. incontinence pads/pants during the day 2. toilet every 3 hours 3. Kegel exercises to increase tone of the pelvic/perineal muscles 4. bent knee sit-ups to increase tone of the abdominal muscles 5. avoid exercises that increase intra-abdominal pressure 6. limit use of coffee, tea, alcohol 7. encourage fluid intake of 1500-2000 milliliters a day 8. restrict fluids 2-3 hours before bedtime iv. urge incontinence a. the state in which one experiences involuntary passage of urine soon after a strong sense of urgency to void b. related factors (etiology) 1. decreased bladder capacity 2. irritation of the stretch receptors in the detrusor muscles causing contractions (e.g., infection, alcohol, caffeine, increased fluids, increased urine concentration, overdistention of the bladder)

c. defining characteristics 1. inability to suppress detrusor muscle contractions until reaching an appropriate receptacle 2. urinary urgency 3. urinary frequency (more than every two hours) d. interventions 1. incontinence pads/pants during the day 2. clothes adapted for quick removal 3. toilet every 2 hours 4. gradually increase intervals between voidings to every 4 hours by consciously delaying voiding 5. Kegel exercises to increase tone of the pelvic/perineal muscles 6. Kegel exercises prior to arising from bed 7. limit use of coffee, tea, alcohol 8. encourage fluid intake of 1500-200 milliliters a day 9. regulate fluid intake at preschedule times to promote predictable voiding pattern 10. restrict fluids 2-3 hours before bedtime k. retention i. the state in which one experiences incomplete emptying of the bladder ii. related factors (etiology) a. obstruction of urine flow, e.g.: 1. prostate gland enlargement, fecal impaction, pregnancy, urethral stricture, urethral edema (especially after childbirth, surgery, or diagnostic examinations [cystography, urethrocystography])

b. alterations in motor or sensory innervation to the detrusor muscle and internal spinchter, e.g.: 1. spinal-cord injury, peripheral nerve trauma, degeneration of peripheral nerves (e.g., diabetic neuropathy) c. inability to relax external spinchter, e.g.: 1. emotional stress/anxiety, muscle tension d. use of medications with urinary retention as an adverse response iii. defining characteristics a. absence of urinary output over several hours b. distended bladder 1. as much as 2000 to 3000 milliliters c. sensation of pressure, discomfort, tenderness, over the symphysis pubis d. overflow incontinence 1. as urine accumulates, pressure in the bladder builds up 2. external urinary spinchter is unable to hold back urine and temporarily opens 3. a small amout of urine is released incontinently (25 to 60 milliliters) 4. as urine is released, pressure in the bladder falls enough to allow the external urinary spinchter to regain control and close iv. interventions a. help client assume a normal position to void b. stimulate reflex voiding center, e.g.: 1. running warm water over perineum, stroking inner thighs, running water in sink c. remove blockage if possible, e.g.: 1. vaginal or rectal packing, fecal impaction d. catheterize with intermittent or indwelling catheter to resolve acute retention l. infection i. state in which one has an infection of a structure in the urinary tract ii. related factors (etiology) a. indwelling urinary catheters b. bladder distention 1. increases pressure on bladder tissue, decreasing blood supply to bladder tissue, making bladder tissue more susceptible to invasion by bacteria

c. shorter urethra in women d. obstruction of the flow of urine resulting in urinary stasis 1. ideal medium for growth of bacteria e. poor perineal hygeine in women, e.g.: 1. wiping back to front f. increased urinary pH 1. most bacteria grow more readily in an alkaline urine, less readily in an acid urine

iii. defining characteristics a. dysuria, urgency, frequency b. fever/chills c. nausea and vomiting d. malaise e. hematuria f. flank pain (costovertebral tenderness) iv. interventions a. encourage 1500 - 2000 milliliters of fluid a day b. decrease urinary pH (acidfy urine), e.g.: 1. meats, eggs, cranberries, prunes, plums c. urinary tract antimicrobials, e.g.: 1. sulfonamides, e.g: a. sulfamethoxazole (Bactrim, Septra) b. sulfisoxasole (Gantrisin) 2. urinary tract antiseptics, e.g.: a. cinoxacin (Cinobac) b. methenamine mandelate (Mandelamine) 3. monobactam and fluoroquinolones, e.g.: a. azetreonam (Axactam) b. ciprofloxacin (Cipro) d. urinary tract analgesic, e.g.: 1. phenazopyridine (Pyridium) 6. Characteristics of urine a. normal i. amount (in 24 hours for adults): 1200 - 1500 ii. color: straw, amber, transparent iii. clarity: clear liquid iv. odor: faint aromatic v. sterility: no microorganisms present vi. pH: 4.5 to 8 vii. specific gravity: 1.010 - 1.025 viii. glucose: not present ix. ketone bodies: not present x. blood: not present b. abnormal i. amount (in 24 hours for adults): under 1200 or over 1500 ii. color: dark amber, cloudy, dark orange, red, dark brown iii. clarity: mucus plugs, viscid, thick iv. odor: offensive v. sterility: microorganisms present vi. pH: under 4.5 or over 8 vii. specific gravity: under 1.010 or over 1.025 viii. glucose: present ix. ketone bodies: present x. blood: occult, bright red 7. Diagnostic studies a. blood tests i. blood urea nitrogen (BUN) a. collection of a specimin of blood to measure the amount of urea nitrogen in the blood b. normal 10 - 20 mg/dl ii. serum creatinine a. collection of a specimin of blood to measure the amount of creatinine in the blood b. normal 1. 0.5 - 1.1 mg/dl = females 2. 0.6 - 1.2 mg/dl = males b. urine tests i. routine urinalysis a. collection of a voided, clean-catch, or catheterized specimin of urine to ascertain the presence of normal and/or abnormal constituents of urine ii. urine for culture & sensitivity a. collection of a clean-catch or catheterized specimin of urine to ascertain the number and types of pathogens in the urine iii. composite urine collections a. collection of all voided or catheterized urine for a specific number of hours (usually 2 - 24) to perform quantitative and qualitative analysis of one or more substances in the urine

iv. creatinine clearance test a. comparison of the amount of creatinine cleared from the blood (as measured by a composite urine collection) with the serum creatinine level (as measured by a serum creatinine blood test) to determine the glomerular filtration rate and, consequently, renal function

b. lab or physician calulates the actual number in the following way: 1. creatinine clearance: C = (U x V) P a. C = clearance rate b. U = creatinine in urine (mg/dl) c. V = volume of urine (ml/24 hours) d. P = creatinine in plasma (mg/dl) c. normal 1. females = 85 to 125 ml/minute 2. males = 95 to 135 ml/minute v. urinary electrolytes

a. collection of a voided, clean-catch, or catheterized urine specimin to ascertain the amount of various electrolytes in the urine vi. urine osmolality a. collection of a voided, clean-catch, or catheterized urine specimin to ascertain the concentration of particles in solution in the urine b. normal = 300 - 1200 mOsm/L c. direct visualization i. cystoscopy and cystourethroscopy a. insertion of scope(s) (cystoscope and/or urethroscope) into the urethra and bladder to directly visualize the urethra and bladder d. indirect visualization i. kidneys, ureters, and bladder (KUB) a. plain radiograph of the abdomen to determine gross anatomic features and/or abnormalities of the kidneys, ureters, and bladder ii. intravenous pyelogram (excretory urography) a. injection of a radiopaque contrast medium into a vein, which is rapidly carried by the blood into the renal vasculature, filtered by the glomeruli, and excreted in the urine, to determine gross anatomic features and/or abnormalities of the kidneys ureters, and bladder

iii. nephrotomography a. sectional radiographs that provide images of the kidneys in different planes to provide information about the gross anatomic features and/or abnormalities of the kidneys

iv. computed tomography a. use of computerized tomograms (serial radiographs) to provide three-dimensional information about the gross anatomic features and/or abnormalities of the kidneys, ureters, and bladder

v. cystography and cystourethrography a. instillation of a radiopaque contrast medium through a urethral catheter to detect gross anatomic features and/or abnormalities of the bladder vi. voiding cystography and cystourethrography (VCUG) a. instillation of a radiopaque contrast medium through a urethral catheter, removing it, and asking the patient to void in order to detect vesicoureteral reflux

vii. renal arteriography a. instillation of a radiopaque constrast medium into an artery (usually femoral) to assess the arterial blood supply to the kidneys viii. percutaneous renal biopsy a. insertion of a trocar through the skin surface into the renal capsule and then passing a biopsy needle through the trocar to obtain a tissue specimin to assess abnormalities of renal cell structure

ix. renography (kidney scan) a. injection of a radionuclide medium into a vein and monitoring its uptake in the kidneys to provide gross information about renal blood flow, structure, and function

x. ultrasonography a. use of sound waves transmitted through the skin to determine gross anatomic features and/or abnormalities of the kidneys, ureters, and bladder 8. Urinary diversion ostomies a. ureterosigmoidostomy i. diversion of urine from the kidneys by surgically implanting the ureters onto the sigmoid colon so that the client excretes urine with feces b. ureteroileosigmoidostomy i. diversion of urine from the kidneys by surgically implanting the ureters onto a piece of small intestestine (called a conduit) and then surgically implanting the conduit onto the sigmoid colon so that the client excretes urine with feces

c. ileal condiut i. diversion of urine from the kidneys by surgically implanting both ureters onto a piece of small intestine (called a conduit) and then surgically implanting the conduit onto the skin surface and creating an opening (stoma)

d. single ureterostomy i. diversion of urine from the kidneys by surgically implanting a ureter onto the skin surface and creating an opening (stoma) e. bilateral ureterostomy i. diversion of urine from the kidneys by surgically implanting both ureters in separate locations onto the skin surface and creating two openings (stomas) that are fairly wide apart

f. transureterostomy i. diversion of urine from the kidneys by surgically implanting both ureters onto the skin surface and creating one opening (stoma) g. double-barrel ureterostomy i. diversion of urine from the kidneys by surgically implanting both ureters close together onto the skin surface and creating two openings (stomas) that are fairly close together

h. vesicostomy i. diversion of urine from the bladder by surgically implanting the bladder onto the skin surface and creating an opening (stoma) i. nephrostomy i. diversion of urine from the pelvis of one or both kidneys by inserting drainage tubing into the pelvis of one or both kidneys end