Urinary System: Anatomy, Function, and Assessment

• This chapter covers the urinary system's function, assessment, and therapeutic measures.

Urinary Anatomy and Physiology

• The urinary system includes two kidneys, two ureters, the urinary bladder, and the urethra.

Kidney Function

• The kidneys form urine and regulate water excretion/conservation, electrolyte balance, and acid-base balance.
• They also activate vitamin D, produce erythropoietin, and produce renin.

Ureters, Bladder and Urethra

• Ureters carry urine from the kidneys to the bladder
• The bladder temporarily stores urine before elimination.
• The urethra carries urine from the bladder to the outside of the body.

Normal Urine Characteristics

• Normal urine output is 1,000 to 2,000 mL per 24 hours.
• Normal urine color ranges from pale yellow to amber.
• Normal urine appearance is clear.
• Specific gravity ranges from 1.005 to 1.030, where lower values mean dilute and higher values mean concentrated.
• Normal urine pH is between 4.5 and 8.0.
• Urine consists of 95% water, along with waste products like urea, creatinine, and uric acid.

Aging Changes

• With aging, renal mass decreases, and renal flow can decrease by 50%.
• Tubular function declines, bladder muscles weaken, and bladder capacity decreases.
• The voiding reflex is delayed in older adults.

Nursing Assessment

• Kidney disease can affect every body system.
• Health history should include questions about flank pain, burning during urination, edema, shortness of breath, and weight gain.
• Assess the patient's fluid intake and functional ability.

Physical Assessment

• High blood pressure can indicate kidney disease.
• Crackles in the lungs suggest fluid overload.
• Edema is indicative of fluid overload.
• Daily weights are the best indicator of fluid balance.
• Accurate intake and output measurement is critical for medication and fluid orders.
• Skin may have a yellow or gray cast, and uremic frost may be present.

Laboratory Tests

• Urinalysis should use a first morning specimen, unless cytology is required.
• Collect 10 mL of urine for urinalysis.
• Examine the urine within 1 hour or refrigerate it.
• Random specimens are collected for cytology.
• Composite urine specimens are collected over 24 hours, beginning after the patient voids and discards the initial urine.
• An incomplete urine collection can cause inaccurate results.
• Urine culture identifies organisms present, often bacteria.
• Collect urine before starting antibiotics.
• Sensitivity tests identify which antibiotics will be effective.
• Renal function tests include serum creatinine (Cr), blood urea nitrogen (BUN), and serum uric acid.
• Creatinine clearance test and glomerular filtration rate (GFR) are also important renal function indicators.

Radiological Studies

• Kidneys-ureter-bladder x-ray (KUB) can reveal tumors, swollen kidneys, and kidney stones.
• Pyelograms image the renal pelvis, calyces, and ureter.
• An IV pyelogram involves injecting contrast IV and taking serial x-rays.
• A retrograde pyelogram involves introducing contrast through the ureter.
• An antegrade pyelogram introduces contrast via percutaneous needle puncture into the renal pelvis.
• For IV pyelograms, check allergies and creatinine levels before the test.
• Hydration is important before and after the procedure.
• IV contrast media is injected to outline renal structures.
• Renal angiography involves checking allergies and creatinine/GFR before the test.
• Dye visualizes renal arteries.
• Post-test, check distal pulses and dressings.

Endoscopic Procedures

• Cystoscopy involves inserting a cystoscope into the bladder through the urethra.
• Retrograde pyelogram involves injecting contrast media into the kidney pelvis and taking x-rays.
• Monitor urine output postprocedure.
• Renal ultrasound uses noninvasive sound waves to examine the urinary tract.
• It requires no special preparation.
• Renal ultrasound can reveal kidney enlargement, kidney stones, chronic infection, and tumors.
• Renal biopsy can be percutaneous or through a small incision (open).
• Precare includes NPO status and a mild sedative.
• Postcare involves frequent vital sign monitoring and observation for bleeding at the biopsy site and in urine.
• Apply a pressure dressing after the procedure.

Urinary Incontinence Types

• Stress incontinence is involuntary urine loss from increased abdominal pressure.
• It is associated with coughing, laughing, sneezing, or other activities.
• Urge incontinence is involuntary urine loss with an abrupt, strong desire to void.
• Functional incontinence occurs when a person can't reach the toilet due to environmental barriers or physical/mental limitations.
• Overflow incontinence is involuntary urine loss associated with bladder overdistention.
• Total incontinence is continuous, unpredictable urine loss.

Urinary Retention

• Acute causes include anesthesia, medications, and local trauma to urinary structures.
• Chronic causes include enlarged prostate, medications, strictures, and tumors.
• Monitor urine output and bladder distention.
• A bladder scan can measure residual urine volume.
• A residual volume of 150 to 200 mL indicates the need for treatment.

Urinary Catheters

• Justifiable reasons for indwelling catheters include burns, neurogenic bladder, shock, and urinary tract obstruction.
• Urinary incontinence is NOT a justification for indwelling catheters.
• Urinary catheters increase the risk of infection.
• Intermittent catheterization is the best option, as it reduces the risk of infection.
• Patients may self-catheterize.
• A suprapubic catheter is an indwelling catheter inserted through an incision in the lower abdomen into the bladder.

This lesson explores the urinary system, including the kidneys, ureters, bladder, and urethra. It details kidney functions like urine formation, electrolyte balance, and hormone production. It also covers normal urine characteristics and methods of assessment.