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Genitourinary System - Vocabulary Flashcards

Urinary Elimination

  • Urine is a waste product produced by the kidneys, stored in the bladder, and excreted via the urethra.
  • Basic processes of the renal system:
    • Regulation of body fluid volume and composition
    • Elimination of metabolic wastes
    • Synthesis, release, or activation of hormones:
    • Erythropoietin
    • Renin
    • Vitamin D
    • Regulation of blood pressure

Urine Production

  • The nephron is the functional unit of the kidney and is composed of:
    • Renal corpuscle (glomerulus and Bowman's capsule)
    • Proximal tubule
    • Loop of Henle
    • Distal tubule
    • Collecting duct
  • The glomerulus is a capillary network.
  • The nephron’s role:
    • Filter water-soluble substances from the blood
    • Reabsorb filtered nutrients, water, and electrolytes
    • Secrete waste

Urine Analysis

  • pH: Normal urine pH is slightly acidic (around 5-6). High or low pH is related to kidney problems, respiratory disorders, or diet-related factors.
  • Specific gravity: indicates urine concentration to assess kidney function. Low = overhydration; High = dehydration or kidney disease.
  • Protein: presence indicates kidney disease or damage (proteinuria).
  • Glucose: presence indicates diabetes or uncontrolled blood sugar (glycosuria).
  • Ketones: produced when body breaks down fat for energy; presence indicates uncontrolled diabetes or fasting/starvation.
  • Blood: hematuria can suggest kidney stones, infections, or injury.
  • Nitrite: presence suggests bacterial infection, often UTIs.
  • Leukocyte esterase: enzyme in white blood cells; presence suggests infection or inflammation in the urinary tract.

Nephrolithiasis (Kidney Stones)

  • Stone composition: Calcium (oxalate and phosphate) is the most common component.
  • Predisposing factors:
    • Low calcium intake
    • High oxalate intake
    • High animal protein intake
    • High sodium intake
    • Low fluid intake
    • Most common cause of stone formation: dehydration
  • Clinical manifestations:
    • Pain: severe, shooting, localized in the lateral lower back (flank) at the costovertebral angle (CVA)
    • Hematuria
  • Treatment:
    • Pain control
    • Fluids
    • Possible surgical removal
    • Extracorporeal shockwave lithotripsy (ESWL)
  • Prevention:
    • Increase fluid intake
    • Reduce dietary oxalate
    • Regulate animal protein intake
    • Limit sodium intake
    • Increase calcium-rich foods — calcium binds oxalate in the stomach/intestines before reaching kidneys, helping oxalate leave the body and reduce stone formation.

Urinary Incontinence

  • In adults, incontinence is generally a sign rather than a diagnosis and often due to conditions that alter urinary tract structure or function.
  • Voiding can be impaired by:
    • Muscular contraction problems
    • Neural transmission issues
    • Hormonal stimulation issues
    • Mechanical factors
  • Temporary incontinence may result from medications, illness, immobility, or constipation.
  • Stress incontinence:
    • Occurs with coughing, sneezing, or laughing
    • Pelvic floor dysfunction; pelvic muscles can be strengthened by Kegel exercises
  • Urge incontinence (overactive bladder):
    • Leakage with a strong urge to void (urgency), nocturia, and frequency
    • May be due to neurological conditions like stroke, Parkinson’s disease, or MS
  • Overflow incontinence:
    • Urine volumes exceed bladder capacity
    • Causes: BPH, fecal impaction, obstruction
  • Functional incontinence:
    • Normal bladder control but impaired ability to reach toilet facilities (e.g., due to mobility issues)

Urinary Tract Infection (UTI)

  • Bacteria ascend the urinary tract from the external urethra to the bladder, attaching to the urothelium and triggering acute inflammation.
  • Common organism:
    • Escherichia ext{ coli} (E. coli), a gram-negative bacterium
    • Accounts for 75\%\text{-}95\% of UTIs
  • Can progress to pyelonephritis and bacteremia (urosepsis).
  • Cues (subjective/objective data):
    • Urgency
    • Dysuria (pain with urination)
    • Frequency
    • Hematuria
    • Cloudy, foul-smelling urine
    • Pain in the lower back or flank area
    • Confusion or delirium in the elderly

Pyelonephritis

  • Infection and inflammation of the renal parenchyma, typically ascending from the lower urinary tract through the ureters to the kidney; most commonly caused by E. coli.
  • Recognize cues (subjective/objective):
    • Triad: Fever, costovertebral angle (CVA) tenderness, nausea/vomiting
    • Flank pain
    • Abdominal discomfort
    • Burning, urgency, and frequency with urination

Polycystic Kidney Disease (PKD)

  • PKD is characterized by growth of fluid-filled cysts in kidney tissue bilaterally, leading to progressive loss of nephrons.
  • PKD may be inherited or acquired.
  • Inheritance and pathophysiology:
    • Cysts grow in the nephrons, filling with glomerular filtrate, eventually enlarging and displacing surrounding tissue
    • Kidney size increases with cyst growth
    • Hypertension often appears early due to compression of renal vessels and activation of the renin–angiotensin–aldosterone system (RAAS)
  • Inherited form is the most common genetic cause of chronic kidney disease leading to kidney failure.

PKD_1: Autosomal-Dominant PKD (ADPKD)

  • Most common inherited form, accounting for 90\% of PKD cases.
  • Genetic mutations typically in PKD1 genes.
  • Usually presents in adulthood; slow to develop; often with normal liver and kidney function early on.
  • Clinical manifestations: pain, hematuria, hypertension.
  • Subarachnoid hemorrhage is a common cause of death in this form.

PKD_2: Autosomal-Recessive PKD (ARPKD)

  • Less common autosomal recessive form arising from mutations in PKHD1 gene.
  • Generally detected within weeks after birth.
  • Clinical manifestations: severe renal failure, impaired lung development, liver fibrosis; cystic dilation causing enlarged kidney.

Other PKD conditions

  • Nephronophthisis – Medullary:
    • Kidneys are small and shrunken with cysts in the medulla or cortex
    • Usually begins in childhood
    • Damage occurs in distal tubules
    • Initial manifestations: polyuria, polydipsia, enuresis
  • Simple PKD:
    • Common in older adults
    • Cysts may be single, multiple, unilateral or bilateral, and vary in size
    • Usually does not affect renal function but can cause flank pain, hematuria, and infection
  • Acquired PKD:
    • Characteristic of end-stage kidney disease (ESKD) in individuals on long-term dialysis
    • May experience hematuria
  • Adenomas may develop in the walls of the cysts

PKD Diagnostic Criteria

  • Diagnosis is confirmed by the presence of three or more kidney cysts verified by ultrasound.

Acute Kidney Injury (AKI)

  • AKI is a rapid onset condition (a few hours to days) where kidneys fail to remove metabolic end products and regulate fluid, electrolytes, and pH balance.
  • Three categories of AKI:
    • Prerenal (hypoperfusion):
    • Marked decrease in renal blood flow
    • Most common cause of AKI
    • Related to hypovolemia, heart failure, cardiogenic shock
    • Clinical manifestations: decreased urine output (UOP), abnormal BUN to creatinine levels (normal 10:1; AKI 15:1 or 20:1), low fractional excretion of sodium
    • Intrarenal (Intrinsic):
    • Damage to structures within the kidney
    • Acute tubular necrosis (ATN) is the most common cause
    • Associated with prolonged renal ischemia, nephrotoxic drugs/metals, intratubular obstruction, acute renal disease, acute glomerulonephritis, and pyelonephritis
    • Postrenal:
    • Obstruction of urine outflow from the kidney
    • Obstruction can occur in the ureter, bladder, or urethra
    • May result from calculi, scar tissue, tumors, infections, trauma, nerve dysfunction, or BPH (most common cause)
    • Obstructions usually do not cause AKI unless one kidney is already damaged
  • Clinical manifestations of AKI are largely centered on reduced UOP and electrolyte/fluid imbalances (noted above in prerenal features)

Chronic Kidney Disease (CKD)

  • Definition: gradual, irreversible loss of kidney function due to nephron damage and chronic deterioration of glomerular filtration (GFR is the rate of filtrate formation as blood passes through the glomerulus; used to measure kidney function).
  • A GFR less than 60 for 3 months indicates kidney damage.
  • Kidney functions progressively decline: regulate fluid volume, blood pressure, metabolic waste excretion, drug excretion, vitamin D conversion, pH regulation, hormone synthesis.
  • Albumin in urine is a marker of kidney damage; GFR reflects kidney function.
  • Causes: diabetes mellitus (DM), hypertension (HTN), chronic NSAID use, polycystic kidney disease, urinary tract obstructions, glomerulonephritis, chronic heart and lung disease.
  • 5 stages of CKD (ESKD is end-stage renal disease at stage 5).

CKD Stages

  • Stage 1: eGFR \ge 90
    • Mild kidney damage; kidneys work as well as normal
  • Stage 2: eGFR = 60-89
    • Mild kidney damage; kidneys still work well
  • Stage 3a: eGFR = 45-59
    • Mild to moderate kidney damage
  • Stage 3b: eGFR = 30-44
    • Moderate to severe damage
  • Stage 4: eGFR = 15-29
    • Severe kidney damage
  • Stage 5: eGFR < 15$$
    • Most severe kidney damage; kidneys are very close to not working or have stopped working (ESKD)