Urinary System Notes

Creatine

  • Creatine enhances the body's ability to regenerate ATP.
  • It volumizes muscle cells, leading to increased size due to water entering the cells.
  • Low muscle mass may indicate malnutrition or liver disease.
  • Intervention: Increase animal protein in diet.
  • Creatine Supplementation beneficial following vegetarian or vegan diet.

Creatinine

  • High creatinine: Greater than 1.3.
  • Signs and symptoms: Renal insufficiency or failure, itching, muscle cramps, nausea, vomiting, edema, nerve pain, and urination issues.
  • Interventions: Increase fluids, manage diet, address kidney or liver issues.
  • Indicates how well kidneys filter.

Blood Urea Nitrogen (BUN)

  • Product made in the liver during protein breakdown.
  • Kidneys filter out urea nitrogen, excreting it in urine.
  • Used to assess kidney function and dehydration.
  • Low value interventions: Educate on food restrictions, monitor intake/output, assess for fluid overload, assess dietary intake (especially protein), encourage nutrient-dense foods, assess for liver disease, and document changes.
  • High values: Over 20, due to decreased renal excretion.

Urinary System Objectives

  • Urinary Catheter and Nursing care is discussed.
  • Math and lab values are on the exam.

Urinary Terms

  • Normal Urine Output: 50-60 mL/hour (low end) with 1500 mL daily intake; aim for 2000 mL/day intake.
  • Void: To empty the bladder.
  • Micturition: Act of urinating.
  • Anuria: Less than 100 mL urine output in 24 hours (e.g., congestive heart failure, kidney failure).
  • Oliguria: Less than 400 mL urine output in 24 hours.
  • Dysuria: Difficulty or painful urination, usually associated with irritated bladder, cystitis, or UTI.
  • Pyuria: Pus or microorganisms in the urine.
  • Enuresis: Involuntary loss of urine (incontinence, bedwetting in children).
  • Nocturnal Enuresis: Bedwetting.
  • Nocturia: Urinating more than once a night, associated with aging and pregnancy.

Historical Facts About Urination

  • Hippocrates: Urine provides a window to the inside of the body.
  • Urine can provide information about diet, hydration, overall health, and kidney function.
  • Ancient methods of urine analysis: Smell, color, transparency, and taste.
  • Ancient Egyptians and Indians: Diagnosed diabetes by the sweet taste of urine.
  • Arabian physicians: Used a color wheel to diagnose diseases based on urine color.
  • Middle Ages: "Piss prophets" diagnosed diseases based on urine color.
  • Uromancy: Fortune telling based on urine characteristics (e.g., bubbles indicate wealth).
  • Ancient Egypt (1350 BC): 70% accuracy in determining pregnancy by urinating on barley and wheat seeds.

Urine Composition and Regulation (Video Notes)

  • Urination removes toxins and maintains water volume/blood pressure.
  • Urine is analyzed for color, smell, clarity, and chemical composition to detect illnesses.
  • Urine is typically 95% water, slightly acidic (pH ~6), and clear to dark yellow depending on hydration.
  • Urine contains over 3,000 chemical compounds; concentration variations indicate body state.
  • Cloudy urine with white blood cells indicates UTI.
  • Sweet-smelling urine with glucose suggests diabetes.
  • Pink urine (without recent beet consumption) indicates internal bleeding.
  • Protein-filled urine suggests pregnancy, overexertion, high blood pressure, or heart failure.
  • Urine production is influenced by blood volume and pressure.
  • Glomerular Filtration Rate (GFR): Amount of blood passing through glomeruli per minute; kidneys regulate this rate.
  • Increased blood pressure causes afferent arterioles to constrict, maintaining constant GFR.
  • Caffeine and alcohol inhibit antidiuretic hormone (ADH) release, leading to increased urination and dehydration.
  • ADH increases water reabsorption in collecting ducts by moving aquaporins to the apical side of cells.
  • Ureters use peristalsis to move urine to the bladder, preventing backflow.
  • Bladder stores urine; inner mucosa consists of transitional epithelium for expansion.
  • Full bladder holds ~500 mL; maxes out around one liter; prolonged overdistension can lead to bursting (unlikely).
  • Urine enters the urethra through the internal urethral sphincter (autonomic control).
  • External urethral sphincter (skeletal muscle) is under voluntary control.
  • Micturition: Bladder stretches, activating stretch receptors, sending nerve impulses to spinal cord and brain.
  • Parasympathetic neurons are excited; sympathetic system is inhibited.
  • Detrusor muscle contracts; internal urethral sphincter opens; external sphincter relaxes.
  • Pons contains pontine storage area (inhibits urination) and pontine micturition center (promotes urination).

Urinary System Anatomy and Physiology

  • Blood travels through kidneys every 30 minutes to filter waste, reabsorb water/electrolytes.
  • Urine passes through ureters to the bladder, then out the urethra.
  • Kidneys:
    • Located behind the gut, near the back.
    • Outer part (renal cortex) contains nephrons (functional units).
    • Nephrons contain glomeruli (filter) and tubules (reabsorb).
    • Primary functions: Filter waste, regulate blood pressure, reabsorb/excrete electrolytes/acids/bases.
    • Secondary functions: Erythropoietin (EPO) production, renin secretion (RAAS system), vitamin D activation.
  • Ureters: Transport urine with peristalsis; one-way valve prevents backflow.
  • Bladder: Stores urine; detrusor muscle contracts to facilitate urination; typical urge to void at 200-500 mL.
  • Urethra: Transports urine from bladder to outside of the body.
  • Women: Shorter urethra (1.5 inches), close to vagina/rectum, higher UTI risk.
  • Men: Longer urethra (8 inches), passes through prostate.

Urinary Elimination Process

  • 200-400 mL urine in bladder -> signal to brain -> detrusor muscle contraction -> internal sphincter relaxes (involuntarily) -> external sphincter relaxes (consciously).
  • Characteristics of Urine
    • Color: Yellow (pale if hydrated)
    • Smell: Aromatic (ammonia-like if standing)
    • Odor changes: Asparagus and Brussels sprouts
    • Color changes: Beets
  • Specific Gravity: 1.005-1.030 (density relative to water, solutes cause heaviness)
  • Urine Color Indications (not tested on):
    • Blue: Bacterial infections or medications
    • Dark brown: Liver disease
    • Cloudy: UTI
    • Red/pink: Kidney stones, blood, or beets
    • Clear: Overhydration

Fluid Intake and Output

  • Intake should closely match output.
  • Intake: Feeding tube, water, IVs.
  • Output: Urine, liquid stool, vomit.
  • Insensible water loss: ~900 mL (sweat, breathing, metabolism).
  • Adult Urine Output:
    • Low end: 50-60 mL/hour.
    • Anuria: <100 mL/24 hours.
    • Oliguria: <400 mL/24 hours.
    • Polyuria: Excessive urine, clear with low specific gravity.
  • Daily Intake: 1500-2000 mL.
  • Infants: >1 mL/kg/hour.
  • Adults: 5-6 voids/day.
  • Less output at night due to ADH secretion.

Assessing Hydration Status

  • Measure intake and output.
  • Assess skin turgor and mucous membranes.
  • Monitor blood pressure.
  • Evaluate pulse (rapid and weak indicates dehydration).
  • Observe for edema.
  • Track weight changes.
  • Auscultate lungs for crackles.

Focused Urinary Assessment Questions

  • Normal pattern: Frequency of urination per day.
  • Habits: Water intake, types of fluids (caffeine, alcohol).
  • Urinary diversion/catheter: Presence and functionality.
  • Incontinence: Occurrence and type.
  • Urine description: Color, smell, difficulty urinating (dysuria, pyuria).
  • Lifestyle questions: Constipation, nocturia.
  • Occupation: Holding urine due to job demands.
  • Surgery: Urinary system/pelvic area surgeries.
  • Other conditions: Obesity, diabetes.
  • Difficulty starting/stopping stream: Prostate issues.
  • Family history: Kidney stones, kidney disease.
  • Medications: Anticholinergics, nephrotoxic drugs, diuretics.
  • Children: Toilet training, accidents, bedwetting.

Developmental Considerations

  • Newborns have immature kidneys with poor water reabsorption, leading to frequent urination (up to 25 times/day).
  • Target output for newborns/infants/small children is >1 mL/kg/hour.
  • Toilet Training
    • Typically occurs between 18 months and 3 years.
    • Boys usually later than girls.
    • Normal until 7 yo.
    • Requires recognition of need to pee, control of external sphincter, communication, and ability to remove clothes.
  • Older Adults
    • Nephrons decrease with age, reducing bladder functionality.
    • Bladder elasticity decreases.
    • Nocturia is common.
    • Increased risk of retention, frequency, and leakage (though not normal).
    • ADH production decreases.

Factors Affecting Urination

  • Diet
    • Caffeine: Diuretic, bladder irritant.
    • Alcohol: Impairs ADH release.
    • Salt: Promotes water retention.
  • Activity
    • Hot weather promotes perspiration and respiration
  • Psychological Factors
    • Privacy/dignity: Shuttered bladder
    • Time:
      • Lack of time -> Retention
  • Sociocultural Factors
    • May not want to ask for help to bathroom.
  • Medications
    • Diuretics: Increase urine output.
    • Anticholinergics: Benadryl.
    • Be aware of decreased kidney function in elderly people for medications.
  • Pathological Conditions
    • Kidney stones: Obstruction.
    • Prostate issues: Benign prostatic hyperplasia (BPH), enlarged prostate.
    • Infection: UTI.
    • Fever: Increased insensible loss.
  • Indirect Causes
  • Constipation: Pressure on bladder.
    • Neurogenic bladder: Lack of sensation of need to urinate (spinal nerve injuries).
    • Cardiovascular Problems: Congestive heart failure, blood pressure issues.

Urinary Tests and Specimen Collection

  • General Guidelines
    • Explain procedure to patient.
    • Provide peri wipes.
    • Instruct on proper cleaning technique before collecting specimen.
      • Females: Front to back.
      • Males: Pull foreskin back (if uncircumcised), clean urinary meatus down.
    • A routine urinalysis (UA) is not sterile; sample can be collected from a “sassy hat”.
    • For infants, use a collection bag.
    • For midstream collection:
  • Instruct patient to start urinating, stop midstream, collect sample, then finish.
  • Sterile Sample from a Catheter
    • Clamp the tubing to allow urine to collect (remove clamp within 30 minutes).
    • Clean the collection port with antiseptic for at least 15 seconds.
    • Use a non-needle syringe to withdraw urine.
    • Empty a catheter drainage bag, remove any securement devices.
    • Deflate the catheter balloon completely before removal.
    • Twenty-four Hour Urine Specimen
      * Discard the first void, collect all urine for 24 hours, and save the last void.