Comprehensive Notes: Disorders of the Bladder and Lower Urinary Tract (Ch 35)

Anatomy and Structure of the Bladder

  • Bladder parts include the Fundus (body) and Neck (posterior urethra).
  • Urine travels from the kidneys to the bladder via the ureters.
  • Ureters enter the bladder bilaterally at a location toward the base and close to the urethra.
  • Trigone: the triangular area bounded by the ureters and the urethra.

Four Layers of the Bladder

  • Outer Serosal Layer: covers the upper surface; continuous with the peritoneum.
  • Detrusor Muscle: a network of smooth muscle fibers.
  • Submucosal Layer: loose connective tissue.
  • Inner Mucosal Lining: transitional epithelium (urothelium).

Neurologic Control of Bladder Function

  • Three main levels of neurologic control:
    • Spinal cord reflex centers: S1\text{-}S4 (sacral) and T11\text{-}L2 (thoracolumbar).
  • Innervation:
    • Pelvic nerve: innervates the detrusor muscle.
    • Pudendal nerve.
    • Hypogastric nerve.
  • Higher centers:
    • Micturition center in the pons.
    • Cortical and subcortical centers.

Question 1

  • Is the following statement True or False? The micturition reflex involves both sympathetic and parasympathetic input.

Answer to Question 1

  • True. Rationale: The reflex is both conscious and unconscious.

Storage and Emptying of Urine: Neurophysiology

  • Urine storage and emptying involve both involuntary (autonomic nervous system) and voluntary (somatic nervous system) control.
  • Parasympathetic nervous system promotes bladder emptying.
  • Sympathetic nervous system promotes bladder filling.
  • Striated muscles in the external sphincter and pelvic floor provide for voluntary control of urine.
  • Emphasizes low-pressure urine storage to prevent leakage during filling.

Autonomic Nervous System (ANS) Drugs and Receptors

  • Nicotinic receptors:
    • Location: sympathetic neurons.
    • Effect: increase bladder storage.
  • Muscarinic receptors:
    • Effect: inhibit sympathetic neurons.

Urine Tests and Studies

  • Laboratory and Radiographic Studies: general urine tests and x-rays.
  • Urodynamic Studies include:
    • Uroflowmetry
    • Cystometry
    • Urethral pressure profile
    • Sphincter electromyography
    • Ultrasound bladder scan

Question 2

  • Increased Post-Void Residual (PVR) volumes are the result of _.
    • Options: Hematuria | Detrusor muscle weakness | Infection | Drug treatment

Answer to Question 2

  • B. Detrusor muscle weakness
  • Rationale: Detrusor muscle weakness results in decreased voiding pressure and therefore greater volume left in the bladder (increased PVR).

Alteration in Bladder Function

  • Types:
    • Urinary obstruction with retention or stasis of urine.
    • Urinary incontinence with involuntary loss of urine.
  • Causes:
    • Structural changes in the bladder, urethra, or surrounding organs.
    • Impairment of neurologic control of bladder function.

Signs of Outflow Obstruction and Urine Retention

  • Bladder distention.
  • Hesitancy.
  • Straining when initiating urination.
  • Small and weak stream.
  • Frequency.
  • Feeling of incomplete bladder emptying.
  • Overflow incontinence.

Common Causes of Neurogenic Bladder

  • Stroke and advanced age.
  • Parkinson disease.
  • Spinal cord injury.
  • Injury to the sacral cord or spinal roots.
  • Radical pelvic surgery.
  • Diabetic neuropathies.
  • Multiple sclerosis.

Spastic Bladder Dysfunction

  • Failure to store urine.
  • Neurologic lesions above the level of the sacral cord allow neurons in the micturition center to function reflexively without CNS control.

Flaccid Bladder Dysfunction

  • Bladder emptying is impaired.
  • Neurologic disorders affect motor neurons in the sacral cord or peripheral nerves that control detrusor muscle contraction and bladder emptying.
  • Nonrelaxing external sphincter: inadequate relaxation of the external sphincter.

Goals of Treatment for Neurogenic Bladder Disorders

  • Prevent bladder overdistention.
  • Prevent urinary tract infections.
  • Prevent potentially life-threatening renal damage.
  • Reduce undesirable social and psychological effects of the disorder.

Treatments for Neurogenic Bladder Disorders

  • Catheterization.
  • Bladder retraining.
  • Pharmacologic manipulation.
  • Surgical procedures.

Question 3

  • Which of the following is not a cause of neurogenic bladder?
    • Parkinson disease | Spinal cord injury | Alzheimer disease | Injury to the sacral cord or spinal roots | Radical pelvic surgery

Answer to Question 3

  • C. Alzheimer disease
  • Rationale: Alzheimer disease is primarily a cognitive condition, not motor-related.

Urinary Incontinence Types

  • Stress Incontinence: involuntary loss of urine during coughing, laughing, sneezing, or lifting; increases intra-abdominal pressure.
  • Urge Incontinence / Overactive Bladder: involuntary loss of urine associated with a strong desire to void (urgency).
  • Functional Incontinence: cognitively incapable of recognizing the need to urinate, and thus urinates when the bladder is full.

Incontinence Types (continued)

  • Overflow Incontinence: involuntary loss of urine that occurs when intravesical pressure exceeds the maximal urethral pressure due to bladder distention in the absence of detrusor activity.
  • Mixed Incontinence: combination of stress and urge incontinence.

Treatment Options for Incontinence

  • Management depends on the type of incontinence, accompanying health problems, and the person’s age.
  • Behavioral and pharmacological measures.
  • Exercises to strengthen the pelvic muscles (pelvic floor training).
  • Surgical correction when appropriate.
  • Noncatheter devices to obstruct urine flow or collect urine.
  • Indwelling catheters.
  • Self-catheterization.

Elderly Incontinence

  • Overall capacity of the bladder is reduced.
  • Urethral closing pressure is reduced.
  • Detrusor muscle function declines with aging, leading to larger PVR volumes.
  • Contributing factors include advancing age, restricted mobility, increased medication, comorbid illness, infection, stool impaction.

Bladder Cancer

  • Signs include: increased frequency, urgency, dysuria, hematuria.
  • Cancerous lesion types: superficial, invasive.

Diagnostic Measures for Cancer of the Bladder

  • Cytologic studies.
  • Excretory urography.
  • Cystoscopy.
  • Biopsy.
  • Ultrasonography.
  • CT scans.
  • MRI.

Treatment Methods for Bladder Cancer

  • Treatments depend on the cytologic grade of the tumor and its degree of invasiveness.
  • Methods include:
    • Surgical removal of the tumor.
    • Radiation therapy.
    • Chemotherapy.