Handbook of Genetic Counseling/Incontinence


General InformationEdit

  • Refers to inability to retain urine in bladder
  • Due to neurologic or mechanical disorder
  • Normal bladder function
    • Detrusor muscle provides propulsive force for emptying bladder
      • Smooth muscle under parasympathetic autonomic control
      • Involves pelvic nerves from sacral spinal cord
    • Layer of smooth muscle of trigonal part of bladder acts as involuntary internal sphincter
      • Helps prevent incontinence even if no voluntary control
      • Innervated by motor fibers from T11 to L2
    • External sphincter and perineal muscles under voluntary control of pudendal nerves
    • Sensory tracts of pain, temperature, and distention pass from bladder to pelvic nerves to sacral spine to medulla of brain to cortical centers
  • Infants and adults with spinal damage above S2 urinate spontaneously when bladder fills

Causes of IncontinenceEdit

  • Detrusor instability
    • Bladder prone to uncontrollable contractions
    • Caused by damage to inhibitory neural pathways (70% of incontinence among elderly)
      • Cerbrovascualr accidents
      • Alzheimer's disease
      • Neoplasia
      • Hydrocephalus (?maybe?)
    • Could also be caused by bladder or pelvic infection or tumor, fecal impaction, uterine prolapse, and prostate hypertrophy
    • May be treated with Imipramine or calcium channel blockers
  • Stress incontinence
    • Common in postmenopausal parous women
    • Structures of female urethra atrophy when deprived of estrogen
      • Pass urine under increased abdominal pressure during coughing, sneezing, climbing stairs
      • Physical activity may result in small amount of urine escaping
  • Mechanical incontinence
    • Congenital anomalies, extrophy of bladder, patent urachus, and ectopic ureteral openings
    • Correctable by surgery only
    • May also be caused by prostate surgery, pelvic surgery, or irradiation of uterus or rectum
  • Overflow or paradoxical incontinence
    • Large residual volumes of urine
    • Secondary to obstruction at bladder neck or urethra, or neurologic damage
    • May occur in diseases that produce autonomic peripheral neuropathy
      • Diabetes mellitus, uremia, hypothyroidism, chronic alcoholism, Guillain-Barre syndrome, collagen vascular diseases, and toxic neuropathy caused by carcinomas
      • Also may be due to prolonged distension of bladder
    • May be treated surgically if obstruction or with bethanechol chloride
  • Psychogenic and functional incontinence
    • Occurs in children and some adults
    • May be to draw attention to themselves
    • May have psychological cause from abuse or other traumatic experiences
  • Enuresis
    • Involuntary passage of urine at night during sleep
    • Considered normal under age of 2 years as neurological controls are still developing
      • Approximately 10% of children have some degree of enuresis beyond age of three
        • May be due to delay in maturation of bladder control
        • May be familial
      • Usually ceases by age of puberty unless disease interferes
        • Urinary tract infections, obstructive lesions, neurovesical dysfunction, and polyuric conditions that overload the bladder
        • Usually incontinent during the day also if one of these conditions


  • "Dysuria, Frequency and Urgency, Incontinence, and Enuresis." Principles of Internal Medicine (1994): 240-241.


The information in this outline was last updated in 2002.