Handbook of Genetic Counseling/Incontinence

Incontinence

General Information

 * 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 Incontinence

 * 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

Reference

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