Introduction to the Urinary System PDF

(1) Anatomy of the Urinary System a. The urinary system is largely responsible for maintenance of homeostasis (balance) in the body. b. The urinary system consists of two kidneys, two ureters, the bladder, and the urethra. c. The primary function of the kidneys is to remove waste, excess wa...

(1) Anatomy of the Urinary System a. The urinary system is largely responsible for maintenance of homeostasis (balance) in the body. b. The urinary system consists of two kidneys, two ureters, the bladder, and the urethra. c. The primary function of the kidneys is to remove waste, excess water, and electrolytes from the blood and concentrate them into urine. The kidneys also secrete erythropoietin to stimulate production of red blood cells. It is released in response to decreased levels of oxygen in body tissue 1. Lies behind the parietal peritoneum and are 4 to 5 inches (10 to 12 cm) long, 2 to 3 inches (5 to 7.5 cm) wide, and about 1 inch (2.5 cm) thick. 2. The right kidney is slightly lower than the left due to the location of the liver. 3. Surrounded by a layer of adipose tissue. 4. Hilus: a notch found near the center of the medial (inside) border where the ureter blood vessels and nerves enter and exit the kidney. (2) Gross Anatomy of the Kidney: Video link: Anatomy of the Kidney https://www.youtube.com/watch?v=7bpTiqe5R6c (1) Renal capsule: outer covering of the kidney made of strong connective tissue. (2) Renal cortex: just beneath the capsule and contains 1.25 million renal tubules. (3) Renal medulla: lies beneath the cortex and is darker in color. (a) Contains the triangular pyramids. (b) Papillae: narrow points of the pyramids that drain urine into the calyces. (c) Calyces drain into the renal pelvis. (d) Renal pelvis is the upper extension of the ureters. (e) Ureters drain urine into the bladder. (f) Urine is excreted from the bladder via the urethra. (3) Microscopic Structure of the Kidney: (1) Nephron: functional unit of the kidney. (a) More than 1 million per kidney. (b) Responsible for filtering the blood and processing the urine. (c) Three major functions: D-1 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  1. Control body fluid levels by selectively removing or retaining water. 2. Assist with the regulation of the pH of the blood. 3. Remove toxic wastes from the blood. (d) Two main structures: renal corpuscle and renal tubule. (2) Renal corpuscle: (a) Glomerulus: tightly bound network of capillaries. 1. Blood enters the glomerulus via the afferent arteriole. 2. Blood leaves the glomerulus via the efferent arteriole. 3. The difference in diameter between the afferent and efferent arteriole controls the rate of glomerular filtration. (b) Bowman's capsule: The cuplike structure that encapsulates the blood filtrating system of the kidney (the glomerulus). (3) Renal tubule: (a) Consists of proximal convoluted tubule, loop of Henle/nephron loop, distal convoluted tubule and collecting duct. (b) Glomerular filtrate (Serum that is forced out of the blood into the Bowman's capsule) travels through tubule: 1. Water and electrolytes (Na+, K+, Cl-, HC03-, etc.) are reabsorbed into the body or secreted into the tubule to form urine. 2. Reabsorbed water and electrolytes re-enter the blood stream, joining the blood cells and protein, in the peritubular capillary network. 3. Absorption and secretion are controlled by the needs of the body to maintain homeostasis. 4. Anti-diuretic hormone (ADH) and aldosterone are secreted by the endocrine system to help the kidneys maintain fluid and electrolyte balance. (c) The juxtaglomerular apparatus is microscopic structure in the kidney that regulates the function of each nephron. It is named for its proximity to the glomerulus; it’s found between the vascular pole of the renal corpuscle and the returning distal convoluted tubule of the same nephron. Regulates systemic blood pressure and filtrate formation. (d) When systemic blood pressure decreases, the juxtaglomerular cells have a decreased stretch which then leads to their release of renin. Renin activates renin- angiotensin mechanism which leads to hypertension. (e) Secreted water and electrolytes and waste products travel through the collecting duct and out of the kidney as urine. (4) Three phases of urine formation: D-2 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  (a) Filtration of water and blood products occurs in the glomerulus of Bowman’s capsule. (b) Reabsorption of water, glucose, and necessary ions back into the blood occurs primarily in the proximal convoluted tubules, Henle’s loop, and the distal convoluted tubules. (c) Secretion of certain ions, nitrogenous waste products, and drugs occurs primarily in the distal convoluted tubule. This process is the reverse of reabsorption; the substances move from the blood to the filtrate. (5) Hormonal influence on nephron function: (a) When body experiences increased fluid loss through hemorrhage, diaphoresis, vomiting, diarrhea or other means, volume is depleted, and blood pressure will drop. (b) The posterior gland releases antidiuretic hormone (ADH) which causes the cells of the distal convoluted tubules to increase their rate of water reabsorption. Review Box 50.1 “Major Functions of the Kidneys” & Functions of the Parts of the Nephron in the Urine Formation. (Page 1651) (6) Urine Composition and Characteristics: (1) Urine formation: Glomerular filtration, tubular reabsorption, and secretion; 1000 to 2000 mL of urine formed each day which is influenced by several factors such as mental or physical health, oral intake, and blood pressure. (2) Urine is 95% water, and the remainder is nitrogenous waste and salts. (3) Normal urine is yellow because of urochrome, a pigment resulting from the body’s destruction of hemoglobin. (4) Fluid and electrolyte control: Maintain correct balance of fluid and electrolytes within a normal range by excretion, secretion, and reabsorption. (5) Acid-base balance: Maintain pH of blood at normal range by directly excreting hydrogen ions and forming bicarbonate for buffering. (6) Excrete of waste products: Direct removal of metabolic waste products contained in the glomerular filtrate including nitrogenous waste (breakdown of protein). (7) Blood pressure regulation: Regulation of blood pressure by controlling the circulating volume and renin secretion. (8) Red blood cell (RBC) production: Secretion of erythropoietin, which stimulates bone marrow to produce RBCs. (9) Regulation of calcium-phosphate metabolism: Regulation of vitamin D activation and electrolyte status. D-3 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  (10) Urine is slightly acidic, with a pH of 4.6 to 8 and a specific gravity of 1.003 to 1.030. Healthy urine is sterile, but at room temperature it rapidly decomposes and smells like ammonia because of the breakdown of urea. Urine abnormalities to be discussed in diagnostics. Urine abnormalities to be discussed in Laboratory and Diagnostic Examinations 4. Ureters: transport urine from the kidneys to the bladder. (a) Once urine is formed in the nephrons it passes to the paired ureters. Ureters are extensions of the renal pelvis and extend downward 10 to 12 inches (25 to 30 cm) to the lower part of the urinary bladder. (b) As the ureters enter the bladder (at the ureterovesical junction), internal mucous membrane folds act as a valve to prevent backflow of urine. 5. Bladder - collects and stores urine. The urethra transports urine from the bladder to the outside of the body during elimination. (a) which is influenced by several factors such as mental or physical health, oral intake and blood pressure. (b) The bladder can hold 750 to 1000 mL of urine. When the bladder contains approximately 250 mL of urine, the individual has a conscious desire to urinate. A moderately full bladder holds 450 mL (1 pint) of urine. 6. Urethra - terminal portion of the urinary system. It is a small tube that carries urine by peristalsis from the bladder out of its external opening, the urinary meatus. a. Normal Aging of the Urinary System: (1) With aging, the kidneys lose part of their normal functioning. (a) Decreased blood supply and loss of nephrons. (b) The filtering mechanism decreases by approximately 50% by the age of 70 as compared to age 40. (c) Women’s bladders lose tone and perineal muscles may relax leading to stress incontinence. (d) Men’s prostate becomes enlarged leading to constriction of the urethra. (e) Incomplete emptying of the bladder for either men or women may increase the possibility of developing a urinary tract infection. (Urinary disorders to be discussed in further lessons). (2) Older Adult Considerations: (Review Lifespan Considerations) green box, page 1652. (a) Urinary frequency, urgency, nocturia and incontinence. These are the leading causes of institutional placement of older adults. D-4 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  1. Weakened musculature in the bladder and urethra. 2. Diminished neurological sensation. 3. Decreased bladder capacity. 4. Effects of medications, such as diuretics. (b) Incontinence can lead to lowered self-esteem and decreased participation in activities outside the home. (c) Inadequate fluid intake (alterations in thirst center regulation), immobility and conditions that lead to frequency, urgency, and urinary stasis increasing the risk of urinary tract infection (UTI). (d) Incontinence can lead to skin breakdown and requires frequent toileting and meticulous skin care. (3) Cultural Considerations: (a) Ensure all appropriate information is gathered at time of initial assessment. To include cultural consideration regarding dietary, time orientation, pain, religious beliefs, taboos, health practices, family roles and views of death. (b) Be aware of specific patient variables that may influence test results: state of hydration, nutritional status, or trauma. (c) A patient’s self-image and sexual performance are affected by altered urinary function. Be sensitive to one’s feelings and guide the interview to ensure all appropriate information is obtained while maintaining the patients dignity. CHECK ON LEARNING: 1. What age-related change in males makes them more prone to UTIs as they age? A: Enlargement of the prostate. RATIONALE: Enlargement of the prostate can constrict the urethra and cause incomplete emptying of the bladder. Incomplete emptying increases the possibility of a UTI. R: Foundation and Adult Health Nursing 8th Ed., Chapter 50, pp. 1652. 2. Should males or females decrease daily fluid intake if they have a UTI? A: Inadequate fluid intake concentrates urine increases the risk of infection in the older adult and increases urinary urgency. R: Foundation and Adult Health Nursing 8th Ed., Chapter 50, pp. 1652 & 1663. Review Summary ELO C: Conducted a review and/or summary on the effects of aging on the urinary system. (a) Urine Tests: (1) Routine Urinalysis: (Review Table 50.2, page 1653) (a) Most commonly used urinary diagnostic test; it evaluates systemic disease, condition of the kidneys, and lower urinary tract. (b) Various reagent test strips are available for clinical use as a quick reference. D-5 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  (c) Purpose: 1. Describe and quantify the characteristics of urine. 2. Help detect metabolic or systemic disease unrelated to renal disorders. (d) Elements of a routine urinalysis include: 1. Evaluation of physical characteristics (color, clarity, and odor). 2. Determination of pH (normal 4.6 - 8.0). 3. Determination of specific gravity (normal 1.003 - 1.030). 4. Detection and rough measurement of protein, glucose, and ketone bodies (not normally found in urine). 5. Examination for red and white blood cells and crystals (not normally found in urine). (2) 24-hour Urine: Measurement of excreted substances by the kidney during a 24-hour period. Provides a better overall measure of kidney function due to hourly changes in rate and secretion throughout the day. (a) Discard first void and note time of the beginning of the 24-hour collection period. Collect and save the next void. Place collection container on ice during the collection period. (b) Common substances measured: 1. Total protein. 2. Creatinine. (Pg. 1654) 3. Urea. 4. Uric acid levels. 5. Catecholamines (Epinephrine and Norepinephrine). (c) Urine Culture & Sensitivity: 1. Confirm suspected infections. 2. Identify causative organisms. 3. Determine appropriate antimicrobial therapy. 4. Periodically screen urine when the threat of a urinary tract infection persists. (d) Urine in the kidneys and bladder is normally sterile, though a small number of bacteria are usually present in the urethra; consequently, urine may contain a variety of organisms. NOTE: This test requires a either a clean-catch or sterile urine specimen; this to minimize contamination from the urethra. (e) Colony count: number of organisms in a milliliter of urine. Used to distinguish between true bacterial infection and contamination. 1. Such counts reliably differentiate between infection and contamination. 2. Requires a clean catch voided midstream collection or catheter specimen in a sterile container. (3) Urine abnormalities D-6 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  1. Albumin in the urine (albuminuria) indicates possible renal disease, increased blood pressure, or toxicity of the kidney cells from heavy metals. 2. Glucose (sugar) in the urine (glycosuria) most often indicates a high blood glucose level. When the blood glucose level rises above the renal threshold (the point at which the renal tubules can no longer reabsorb), the glucose spills into the urine. 3. Erythrocytes in the urine (hematuria) may indicate infection, tumors, or renal disease. Occasionally an individual may have a renal calculus (kidney stone; plural, calculi), and irritation produces hematuria. 4. Ketone bodies in the urine are called ketoaciduria (or ketonuria). It occurs when too many fatty acids are oxidized. This condition is seen with diabetes mellitus, starvation, or any other metabolic condition in which fats are catabolized rapidly. 5. Leukocytes (white blood cells [WBCs]) are found in urine when there is an infection in the urinary tract. (4) Urine Specific Gravity: a. The density of urine is compared with that of water and indicates a patient’s hydration status. b. Decreased by high fluid intake, reduced renal concentrating ability, endocrine disorders such as diabetes insipidus and diuretic use. c. Increased by dehydration, vomiting, diarrhea, diabetic ketoacidosis or hyperglycemic hyperosmolar nonketotic coma and inappropriate secretion of ADH. a. Blood Tests: (1) Blood urea nitrogen (BUN): (a) Determines the kidneys' ability to rid the blood of urea, a non-protein waste, which results from protein catabolism (breakdown). (b) Evaluates renal function and aid in diagnosis of renal disease. (c) Urea is formed by conversion of ammonia in the liver and excreted by the kidneys. (d) Reflects protein intake and renal excretory capacity but is a less reliable indicator than serum creatinine. (e) May also be elevated in congestive heart failure, catabolic state, starvation and large GI blood loss. (f) Normal BUN range is 10 to 20 mg/dl. (2) Serum (blood) creatinine: The serum creatinine test, as with BUN, is used to diagnose impaired kidney function (a) Measures creatinine levels in the blood. D-7 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  (b) Purpose. Creatinine and BUN are excreted entirely by the kidneys, therefore, are directly proportional to renal excretory function. (c) Abnormal elevation in creatinine is caused by: 1. Glomerulonephritis: infection of the glomerulus. 2. Pyelonephritis: infection of the kidney. 3. Acute tubular necrosis: destruction of the tubules of the nephron. 4. Urinary obstruction: blockage of urinary drainage. (d) Creatinine, unlike BUN, is affected very little by dehydration, malnutrition, or liver function. (e) Normal serum creatinine is 0.6 to 1 mg/dl (female) and 0.7 to 1.3 mg/dl (male) lower in women due to less muscle mass. (3) Creatinine Clearance: (a) Creatinine is generated during muscle contraction and then excreted by glomerular filtration. (b) During the testing period, the patient avoids excessive physical activity. (c) An elevated serum level with a decline in urine level indicates renal disease. (4) Prostatic-Specific Antigen (PSA) (normal range is less than 4ng/mL). Typically, older men normally have higher levels than those of younger men. (a) An organ specific glycoprotein produced by normal prostate tissue. (b) Used as a diagnostic to evaluate the prostate health of men being treated for cancer. (c) Elevated PSA results from: 1. Prostate cancer. 2. Benign prostatic hypertrophy. 3. Prostatitis. 4. Normal PSA is less than 4 ng/ml. (5) Urine Osmolality: (a) Determines the number of particles (solute) per volume of water (solvent). (b) Preferred over specific gravity. (c) May be done in conjunction with urine sampling when pituitary disorders are suspected. (d) Provides information regarding the ability of the kidneys to concentrate urine. NOTE: For all urine and blood test send the samples with lab slips immediately to the lab 1. Which blood test is a particularly reliable indicator of kidney function because it is excreted directly from the kidneys and measured levels depend on muscle mass (which fluctuates little)? D-8 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  A: Blood (serum) creatinine RATIONALE: Creatinine is a catabolic product of creatine (used in skeletal muscle contraction). Daily production of creatine depends on muscle mass (does not fluctuate much). Creatinine, as with BUN, is excreted entirely by the kidneys and is directly proportional to renal excretory function. Creatinine level is affected little by dehydration, malnutrition, or hepatic function. R: Foundation and Adult Health Nursing 8th Ed., Chapter 50, pp. 1654. Review Summary ELO D: Conducted a review and/or summary regarding the common diagnostic tests used to determine urinary tract disorders. a. Structural and Functional Tests: (1) Kidney-Ureter-Bladder (KUB) radiography: (a) Radiological procedure to evaluate the general status of the abdomen, and the size, structure, and position of the urinary tract structures. (b) No special preparation necessary. Requires the patient to change positions on the radiography table, which is firm and uncomfortable. (c) Abnormal findings may indicate: 1. Tumors. 2. Calculi. 3. Glomerulonephritis. 4. Cyst. 5. And other conditions (2) Intravenous pyelography (IVP)/ Intravenous Urography (IVU): (a) IVP/IVU evaluates structures of the urinary tract, filling of the renal pelvis with urine, and transport of urine via the ureters to the bladder. A contrasting dye allows assessment of the excretory function of the kidneys. (b) Locates the site of any urinary tract obstructions and assists in the investigation of flank pain, hematuria, or renal calculi. (c) Iodine allergy MUST be determined prior to the study because it is the base of the radiopaque contrast that will be injected into a vein. 1. Identify any previous allergic reaction to iodine, or iodine containing foods, i.e., iodine containing salt, saltwater fish, seaweed products, and vegetables grown in iodine rich soils. 2. Corticosteroids or antihistamines may be ordered to be given prior to testing or, ultrasound may be used as an alternate. (d) Preparation: 1. Kidneys and ureters are positioned in the retro-peritoneal space, causing gas and stool in the intestines to interfere with radiographic visualization. 2. Preparation usually includes a light supper, a non-gas-forming laxative, and NPO status 8 hours before testing. (e) Procedure: 1. Informed consent must be obtained prior to sedation or procedure. D-9 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  2. A warm, flushing sensation and possibly a metallic taste may be experienced when the contrast is injected. 3. Vital signs will be monitored frequently. Radiographs will be taken at various intervals to monitor movement of the contrast. (f) Abnormal findings may indicate: 1. Structural deviations. 2. Hydronephrosis. 3. Calculi within the urinary tract. 4. Polycystic kidney disease. 5. Tumors and other conditions. (3) Retrograde Pyelography: (a) Injection of contrast (radiopaque dye) into ureters to visualize upper urinary tract (ureters and renal pelvis). A sterile cystoscope with catheter is placed aseptically. (b) Retrograde cystography – Radiopaque dye is injected through an indwelling catheter into the urinary bladder to evaluate or determine the cause of recurrent infections. (c) Retrograde urethrography – A catheter is inserted, and dye is injected as in retrograde cystography to assess the status of the urethral structure. (4) Voiding Cystourethrography: (a) Used in conjunction with other diagnostic studies to detect abnormalities of the urinary bladder and urethra. (b) Preparation: 1. Administer an enema before testing. 2. Insert an indwelling catheter into the urinary bladder. (c) Procedure: 1. Contrast is injected to outline the lower urinary tract and radiographs taken. 2. Patient will be asked to void while radio graphics are being taken. 3. Patients may experience embarrassment or anxiety related to the procedure and should be given the opportunity to express their feelings. (d) Abnormal findings may include: 1. Structural abnormalities. 2. Diverticula. 3. Reflux into the ureter. a. Endoscopic Procedures: (1) Visual examinations of hollow organs using an instrument with a scope and light source. (2) Informed consent is necessary. (3) Most often performed in the surgical suite, therefore pre-operative preparation is indicated. D-10 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY (4) Types: (a) Cystoscopy: visual examination to inspect, evaluate, diagnose, and treat disorders of the urinary bladder and proximal structures. 1. The cystoscope is a lighted tube with a telescopic lens. 2. Origin for painless hematuria, urinary incontinence, or urinary retention can be found using this procedure. 3. Preparation: a) Performed with a local anesthetic (instilled into the urethra) and conscious sedation. b) Anti-spasmodic may be administered prior to procedure. c) Patient will be placed in lithotomy position for the procedure and will be awake while the scope is being passed. May cause psychological stress, so allow patients to verbalize feelings and concerns. 4. Procedure: a) Aseptic procedure in which patients will experience a feeling of pressure as the scope is passed. 5. Post-procedure care: a) Hydration to dilute the urine. b) Assess the first voiding post-procedure noting time, amount, color, and any dysuria. Blood- tinged urine is common due to the soft tissue trauma of the procedure for the first initial void. c) Administer prescribed antibiotics and anti-spasmodic medications post-procedure. 6. Additional uses for this procedure include: a) Biopsy samples: carries the risk of post-procedure bleeding because the kidneys receive up to 25% of the cardiac output each minute. b) Urinary samples. (b) Brush Biopsy: 1. Performed with a nylon brush via a ureteral catheter during a Cystoscopy. 2. Specimens obtained from the renal pelvis or calyces. (c) Nephroscopy (Renal Endoscopy): 1. Performed using the percutaneous (through the skin) route and provides direct visualization of the upper urinary structures. 2. Biopsy or urine specimens obtained and/or calculi removed. D-11 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY a. Other diagnostic studies/evaluations: (1) Renal Angiography: (pg. 1655) (a) Evaluates blood supply to the kidneys, evaluates masses and detects potential complications after renal transplant. (b) Preparation: NPO after midnight the night prior to the procedure. (c) Procedure: performed in special procedures/radiology. 1. Catheter is placed through the femoral artery into the renal artery. 2. Contrast is injected to visualize the renal artery. 3. Instruct patients about common experiences during contrast injection – as listed earlier. (d) Post-procedure care: 1. Hydration to flush contrast from kidneys. 2. Bed rest with head of bed flat for several hours after procedure to prevent bleeding/hematoma formation at catheter site. 3. Neurovascular checks (pulse, cap refill) will be assessed very frequently post-procedure; every 15 minutes for 1 hour, then every hour for 24 hours. 4. Alert the physician immediately of any abnormalities or changes. (2) Renal Venography 1. Provides information about the kidney’s venous drainage. 2. Post procedure includes assessment of vital signs and femoral site. 3. Assess for bruising and swelling. 4. Assess pulses distal to the puncture site. 5. Potential complications post procedure include allergic reaction to the dye, bleeding, clots, or injury to the vein. (3) Computed Tomographic Scanning (CT): (a) Non-invasive procedure to determine kidney size and differentiate kidney masses. (b) Visualization of the adrenals, bladder and prostate. (c) May or may not use contrast after initial scan to enhance images. Contrast used when vascular tumors are suspected. (d) Multiple cross-section pictures obtained at several different sites create a three dimensional "map" of the kidney structures. (4) MRI: D-12 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY  (a) Nuclear magnetic resonance used to obtain visual assessment of the urinary structures. (b) Instruct patients that they will hear a repetitive pounding and to be as still as possible. (c) Patients must remove all metal objects. Patients with pacemakers and permanent metal prostheses, i.e., orthopedic hardware, artificial heart valves, cannot undergo MRI. (5) Renal Scan: (a) A series of computer-generated images then is made. No special patient preparation is needed. Check facility policy concerning the disposal of the patient’s urine for the first 24 hours. Pregnant nurses should refrain from caring for patients administered radioactive substances. (6) Ultrasonography: (a) Identifies the kidney's size, shape, position, collecting systems, and adjacent tissues. (b) Other uses include identification of renal cysts or obstruction sites, assistance in needle placement, and drainage of a renal abscess. (c) Non-invasive procedure, therefore, no contraindications exist or preparation of the patient required. (d) Informed consent must be obtained prior to sedation, needle insertion, drainage, or invasive procedures. (7) Transrectal Ultrasound: (a) Instrumentation of the prostate gland provides clear images of prostatic tumors that otherwise may go undiagnosed. (8) Renal Biopsy: (a) Open biopsy: 1. Surgical procedure requiring general anesthesia and routine pre- and post-operative care. 2. Informed consent must be obtained before sedation and procedure. (b) Percutaneous biopsy: 1. Preparation: NPO after midnight the night prior to the procedure. a) Informed consent must be obtained before sedation and procedure. b) Patient may experience pain during procedure despite conscious sedation. c) Patient will be asked to follow simple commands, including holding breath during procedure. 2. Post-procedure care: a) Bed rest for 24 hours. b) Gradual resumption of activities over next 48 to 72 hours. c) Assess for infection, damage to kidneys, hematuria. D-13 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY (9) Urodynamic Studies: (a) Indicated when neurologic disease is thought to be the underlying cause of incontinence. (b) Evaluates the activity level of the urinary bladder muscle (detrusor). (c) This may cause the patient to be embarrassed and somewhat uncomfortable. A simple urodynamic study is cystometrography, in which a catheter is inserted into the bladder and then connected to a cystometer, which measures bladder capacity and pressure. (d) Cholinergic and anticholinergic medications may be administered during urodynamic studies to determine their effects on bladder function. A cholinergic drug, such as bethanechol (Urecholine), stimulates an atonic bladder; an anticholinergic drug, such as atropine, brings an overactive bladder to a more normal level or function. (Medications to be discussed later in this module). D-14 UNCLASSIFIED//CAC-T//FOR OFFICIAL USE ONLY