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Clinical Reference Review of the Genitourinary System

Overview of the Urinary System

  • The urinary system comprises two main parts:
    • Upper urinary tract: Kidneys and ureters.
    • Lower urinary tract: Bladder and urethra.

Pediatric Differences in the Genitourinary System

  • Functionality in Infants:
    • Healthy infants have kidneys functioning proportionally for their body size.
    • However, kidney function may decrease under stress.
  • Development Timeline:
    • By 6 to 12 months, kidney function approaches that of adults.
    • Adult glomerular filtration rate (GFR) is achieved by age 2.
  • Premature Infants:
    • Exhibit reduced reabsorption of glucose, sodium, bicarbonate, and phosphate.
  • Urine Concentration Ability:
    • Young infants are less efficient at concentrating urine due to shorter loops of Henle, affecting their ability to reabsorb.
  • Bladder Position:
    • After birth, the bladder shifts from the lower abdominal cavity into the pelvic cavity during childhood.
  • Urethral Length:
    • Young children possess shorter urethras, increasing the risk for urinary tract infections (UTIs).
  • Bladder Control:
    • Complete bladder control usually achieved by ages 4-5 years.
  • Acute Kidney Injury (AKI):
    • Most children regain normal kidney function after AKI.

Anatomy of the Kidneys

  • Size and Location:
    • Kidneys are bean-shaped, located along the spinal column.
    • Adult kidneys are about the size of a fist; infant kidneys are proportionally larger.
  • Hilum:
    • Indentation where blood vessels, lymphatics, nerves, and ureters enter the kidney.
  • Kidney Composition:
    • Cortex: Outer region containing glomeruli and tubules.
    • Medulla: Inner region containing renal pyramids and tubules.
    • Renal Pelvis: Part of the hilum, extension of the ureter.
  • Ureters and Bladder:
    • Ureters enter the bladder, and bladder filling compresses distal ureters to prevent reflux.
    • Bladder Capacity: Approximately 10 mL/kg of body weight in children.
  • Urethra:
    • Contains internal and external sphincters controlling urination; boys have longer urethras than girls.
  • Nephron:
    • The functional unit of the kidney, includes Bowman’s capsule, glomerulus, proximal tubule, loop of Henle, distal tubule, and collecting duct.
    • Approximately 1 million nephrons exist per kidney, present from birth.

Blood Supply to the Kidneys

  • Blood enters through renal arteries from the abdominal aorta, subdividing to afferent arterioles feeding the glomeruli and draining through efferent arterioles.
  • Peritubular Capillaries: Surround the nephron's tubular components, drainage into the venous system occurs through the renal vein and into the inferior vena cava.

Functions of the Kidneys

  • Major roles include:
    • Fluid and Chemical Balance:
    • Maintained via glomerular filtration, tubular reabsorption, and secretion.
    • Hormonal Functions:
    • Renin Production: Regulates blood pressure; triggered by decreased pressure.
    • Erythropoietin: Stimulates RBC production in bone marrow.
    • Vitamin D Metabolism: Converts vitamin D into its active form for calcium metabolism.

Assessing Genitourinary Dysfunction in Children

  • Nonspecific assessment data include:
    • Altered growth, skeletal anomalies, hypertension, skin lesions, immune dysfunctions.
  • Conditions can range from single acute UTIs to end-stage renal disease (ESRD).
  • Nursing care varies with severity:
    • Hospitalization for acute nephrotic syndrome; less severe disorders managed at home.

Laboratory and Diagnostic Tests for Genitourinary Disorders

  • Urinalysis:
    • Specific Gravity: 1.002–1.030
    • Indicates hydration and renal concentration ability. Higher if protein/glucose present.
    • pH: 4.5–8.0
    • Increased in urinary infections, diet can alter findings.
    • Protein: Negative or trace
    • May indicate renal disease; early morning specimens preferred due to concentration.
    • Glucose: Negative
    • Screens for diabetes; may show in dehydration or renal disease.
    • Ketones: Negative
    • Associated with diabetes or conditions like starvation or prolonged vomiting.
    • Leukocyte Esterase: Negative
    • Indicates possible UTI when present with WBCs.
    • Nitrites: Negative
    • Produced by certain bacteria; can indicate UTI.
    • WBCs and RBCs: 0–2/high-power field; present indicates infection or trauma.
    • Bacteria: None; if present suggests UTI.
    • Casts: None
    • Indicates renal pathology like pyelonephritis.
    • Urine Culture and Sensitivity: Negative or ≤100,000 colonies/mL.
    • For diagnosing UTIs, identifies pathogens and their antibiotic sensitivities.
    • Serum Studies:
    • BUN (Blood Urea Nitrogen):
      • Newborn: 3–12 mg/dL, Infant/Child: 5–18 mg/dL, Adult: 10–20 mg/dL.
    • Serum Creatinine:
      • Newborn: 0.3–1.0 mg/dL, Infant: 0.2–0.4 mg/dL, Child: 0.3–0.7 mg/dL, Adolescent: 0.5–1.0 mg/dL, Adult males: 0.6–1.2 mg/dL, females: 0.5–1.1 mg/dL.
    • Serum Osmolality: 275–295 mOsm/kg; indicates fluid/electrolyte balance.
  • Radiography:
    • KUB (Kidney, Ureter, Bladder): Assesses renal stones.
    • Cystoscopy: Examines bladder and urethra; may require general anesthesia.
    • CT Scan: Imaging for renal tumors, may require sedation and NPO.
    • VCUG (Voiding Cystourethrogram): Assesses urine reflux into ureters.
    • DMSA Renal Scan: Visualizes kidney structures, assesses pyelonephritis.
    • Renal Ultrasonography: Noninvasive assessment of kidney function and structure.
    • Urodynamic Studies: Measures bladder function; assesses voiding dysfunction.

Enuresis: Urinary Control in Children

  • Definitions:
    • Enuresis involves difficulties with urinary control, divided into nocturnal (night) and diurnal (day).
    • Primary Enuresis: Child has never achieved dryness.
    • Secondary Enuresis: Child has been dry for 6-12 months before wetting resumes.
Etiology
  • No single cause; risk factors include:
    • Physical factors:
    • Decreased bladder capacity, UTI, neurologic alterations, constipation, obstructive sleep apnea.
    • Emotional factors:
    • Increased stress, family disruptions.
    • Must consider sexual abuse in secondary enuresis cases.
Incidence
  • 15% of children at age 6 experience primary nocturnal enuresis; decreases with age.
    • Higher incidence in boys and children with a family history.
Pathophysiology
  • Involves maturational delay in CNS awareness of bladder fullness; daytime control usually occurs before nighttime.
  • Manifestations of nocturnal and diurnal enuresis, diagnostic evaluations including urinalysis to rule out UTIs.
Therapeutic Management
  • Treatment includes general interventions like limiting fluids after supper, encouraging nighttime voiding, and using reward systems.
  • Alarms for older children, desmopressin acetate for reducing overnight urine production, and addressing constipation are effective strategies.
Nursing Care
  • Assessment of vital signs, child's understanding, voiding patterns, and psychological impact.
  • Nursing diagnosis examples include decreased self-esteem and altered social interaction based on enuresis.
  • Identify and implement solutions, follow-up for efficacy, and adjustments as necessary.

Urinary Tract Infections (UTIs)

  • Characterized by bacteria presence in urine, leading to potential complications such as renal scarring and ESRD.
Etiology
  • Mainly from bacteria ascending from the urethra; common bacterium include Escherichia coli.
  • Risk factors:
    • Urinary tract obstructions, voiding dysfunction, anatomic differences, individual susceptibility (uncircumcised boys), and sexually active adolescent girls.
Incidence
  • 1-3% prevalence in girls, 1% in boys; frequent occurrences in young children.
Pathophysiology
  • Bacteria colonize the perineal area, ascend to bladder.
  • Can cause cystitis or pyelonephritis; pyelonephritis is the most common childhood infection.
Manifestations
  • Symptoms vary by age; common in infants include fever, irritability, and feeding difficulties.
  • For older children: abdominal pain, dysuria, increased frequency, and urgency.
Diagnostic Evaluation
  • Diagnosis confirmed by urinalysis, urine culture (≥100,000 CFUs/mL), and imaging for structural abnormalities if recurrent UTIs occur.
Therapeutic Management
  • Initial treatment for uncomplicated UTI involves a 3-5 day antibiotic course.
  • For pyelonephritis, parenteral antibiotics may be necessary.
  • Prophylactic antibiotics may be warranted in cases of recurrent infections, with careful consideration of resistance risk.

Cryptorchidism

  • Refers to undescended testes, a common condition.
Incidence
  • 3.4% in full-term boys; 30% in premature infants.
Pathophysiology
  • Testes typically descend from the abdomen between 32-36 weeks gestation.
Manifestations
  • Non-palpable testes or repeated ascension; associated with risk for malignancy and torsion.
Management
  • Initial observation is common; surgery (orchidopexy) indicated beyond 6 months for correction.

Hypospadias and Epispadias

  • Hypospadias: Urethral opening located below the typical penile position; may include chordee.
  • Epispadias: Urethral opening above the normal position, less common.

Nursing Care Considerations for Hypospadias

  • Assessment during newborn examination for urinary stream quality; parental education is vital.
  • Plan includes preoperative and postoperative care with emphasis on infection prevention and monitoring.

Acute Poststreptococcal Glomerulonephritis (APGN)

  • Describes kidney disorders resulting from infection; most common type is poststreptococcal.
Etiology and Incidence
  • Immune response to streptococcal infections; common in children aged 5-12 years.
Manifestations
  • Signs include hematuria, edema, hypertension, and possible febrile response.
Evaluation and Diagnostic Findings
  • Diagnosis through urinalysis and blood tests; treatment focuses on supportive care for symptoms and associated renal dysfunction.
Nursing Management
  • Monitoring vital signs, daily weights for edema, patient education, and promoting understanding of the condition.