Incontinence may be due to loss of voluntary control of urination, in which case neurologic disorders are usually the cause, or it may result from overflow of a distended bladder (overflow incontinence), in which case the cause may be bladder neck obstruction or a flaccid neurogenic bladder.
1. Loss of voluntary control. The neurologic causes include multiple sclerosis, neurosyphilis, syringomyelia, encephalitis, cerebral arteriosclerosis, frontal lobe tumors and abscesses, senile dementia, and transverse myelitis from trauma or infection. The local causes are a cystocele (often following a hysterectomy) and a damaged urethral sphincter from prostatectomy.
2. Bladder neck obstruction. Benign prostatic hypertrophy, chronic prostatitis, prostate carcinoma, median bar hypertrophy, vesical calculus, and urethral stricture are important mechanical causes of obstruction.
3. Flaccid neurogenic bladder. Drugs such as atropine, tranquilizers, and anesthetics and diseases of the cauda equina and nervi erigentes such as diabetic neuropathy, poliomyelitis, tabes dorsalis, and cauda equina tumors will cause a flaccid neurogenic bladder with overflow incontinence.
Approach to the Diagnosis
First, exclude stress incontinence with a pad test. Perineal pads are weighed before and after walking and stress for 30 minutes. An increase in weight identifies urine loss. Catheterization and examination, smear, and culture of the urine are essential at the outset. Cystoscopy and cystometric studies are often needed. Surgical repair of a cystocele or a parasympathomimetic drug in cases of a flaccid neurogenic bladder and propantheline bromide (ProBanthine), a parasympatholytic drug, for spastic neurogenic bladders may be all that is necessary. A neurologist and urologist often need to cooperate in the diagnosis and treatment of these unfortunate individuals.
Other Useful Tests
1. Q-tip test (stress incontinence)
2. Sonogram (test for residual urine)
3. Catheterization for residual urine (bladder neck obstruction)
4. CT scan of the lumbar spine (cauda equina tumor)
5. NCV and EMG (neuropathy)
6. Magnetic resonance imaging (MRI) of the brain and spinal cord (multiple sclerosis, e.g.)
7. Psychometric testing (dementia)
8. Serum FSH and LH (menopause)
Case Presentation #55
A 48-year-old white woman is brought to your office by her daughter who complains that she is getting forgetful and frequently wets herself. She is planning to admit her to a nursing home. She denies that her mother abuses drugs but admits she consumes a moderate amount of alcohol and falls occasionally.
Question #1. Utilizing your knowledge of neuroanatomy, what is your differential diagnosis?
You observe that the patient has a wide-based ataxic gait.
Question #2. What is your diagnosis now?