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. Notes The information in this outline was last updated in 2002.