Dificultades para orinar

Vea también los artículos separados sobre Chronic Urinary Retention, Acute Urinary Retention, Incontinencia Urinaria, Detrusor Instability and Irritable Bladder, Nocturia, Urinary Tract Obstruction, Urinary Tract Infection in Adults, Infección Recurrente del Tracto Urinario, Lower Urinary Tract Symptoms in Men, Lower Urinary Tract Symptoms in Women.

Urinary continence and micturition are functions which require:

• The integrity of the organs (bladder, urethra, and voluntary and involuntary sphincters).

• The integrity of the neural pathways responsible for micturition (parasympathetic), continence (sympathetic), and their control and co-ordination.

Apart from the incontinence associated with vesicovaginal fistulae in women, or overflow incontinence associated with a distended bladder in chronic retention, the three principal clinical forms of incontinence are:

• Stress incontinence.

• Urge incontinence.

• Mixed incontinence - combining the two mechanisms.

Voiding difficulties causing discomfort on urination, or retention (chronic or acute), are the reflection of an imbalance between bladder contraction and urethral resistance. The complete list includes the following problems:

• Stress incontinence.

• Urge incontinence.

• Poor flow.

• Intermittent stream.

• Incomplete emptying.

• Straining to void.

• Hesitancy.

• Acute retention.

• Chronic retention.

• Overflow incontinence.

• Urinary tract infection (UTI) from residual urine.

Etiología

Central nervous system (CNS)

May be from:

• Suprapontine lesions - eg, a cerebrovascular event.

• Cord lesions - eg, cord injury, multiple sclerosis.

• Peripheral nerve - eg, prolapsed disc, diabetic or other neuropathy.

• Reflex due to pain - eg with herpes infections.

Medicamentos

• Especially epidural anaesthesia.

• Tricyclics, anticholinergics.

Obstruction

• Prostatic hypertrophy.

• Early oedema after bladder neck repair.

• Uterine prolapse, retroverted gravid uterus, fibroids.

• Quistes ováricos.

• Urethral foreign body, ectopic ureterocele.

• Bladder polyp or cancer.

Bladder overdistension

• After epidural for childbirth.

• Faecal impaction is a cause of retention with overflow.

• Where detrusor weakness is the cause, there is incomplete bladder emptying with dribbling overflow incontinence.

Investigaciones

• Mid-stream specimen of urine (MSU) should always be taken to exclude infection.

• Ultrasound should be performed for residual urine and bladder wall thickness (>6 mm on transvaginal scan associated with detrusor instability).

• Cystourethroscopy is also recommended.

• Uroflowmetry - a rate of <15 mL/second for a volume of >150 mL is abnormal. This test should be performed before any surgery is contemplated.

• Estudios urodinámicos; subtraction cystometry is a subtraction of intra-abdominal pressure from measured intravesical pressure to give detrusor pressure. Intravesical measure is a mix of bladder pressure and intra-abdominal pressure.

Manejo

This will depend on the cause. See links to separate articles above for more detail.

Inestabilidad del detrusor

• Avoid caffeine (mild diuretic, detrusor stimulant).

• Begin bladder training to increase the interval between voiding.

• Anticholinergic drugs are effective - eg, oxybutynin; however there may be problems with compliance:¹²

  • Start with 2.5 mg/12-hourly, increasing slowly up to 5 mg/6-hourly (per 12 hours if elderly).

  • Side-effects include dry mouth, blurred vision, nausea, headache, constipation, diarrhoea and abdominal pain. These are less if modified-release once-daily tablets are used.

  • 30 mg/day of Ditropan XL® may be tolerated (approach this by weekly 5 mg jumps). Tolterodine (eg, 2 mg/12-hourly) is also effective, with a lower side-effect profile.

  • In the majority of cases this is successful, but in those where it is not, intravesical therapies have been introduced (eg, neuromodulation) and alternative drug therapies (eg, vanilloids, botulinum toxin injection), and surgery.³

Incontinencia por estrés⁴

• Pelvic floor muscle physiotherapy may help those with symptoms.

• Although surgery is commonly performed to alleviate or cure stress incontinence, there are non-surgical options that might well be explored and tried before a woman undergoes surgery.⁵

• Minimally invasive techniques (eg, tension-free tape) have been shown to be effective and acceptable to the patient.⁶

• The least drastic treatments are behavioural therapies, chiefly pelvic floor muscle training - Kegel exercises. This method is effective but has the drawback of poor patient compliance.

• Medical management has included hormone replacement therapy and alpha-adrenergic agonists, but questionable results and intolerable risks have shifted this mode to serotonin-norepinephrine reuptake inhibitors, which have CNS action.

• Finally, there are urethral occlusive devices, which have poor acceptance owing to side-effects and difficulty of use.

Nocturia

Vea el artículo separado sobre Nocturia.

Acute retention

This may require catheterisation. A suprapubic catheter should be sited if the catheter will be needed for several days.

• For persistent conditions (eg, neurological conditions), self-catheterisation techniques may be learned (eg, with a LoFric® gel-coated catheter).

• With detrusor weakness, drugs may relax the urethral sphincter or stimulate the detrusor muscle.

• Alpha-blockers (eg, tamsulosin 400 micrograms/24-hourly) relax the bladder neck; diazepam relaxes the sphincter.

Obstructive causes

Operative measures may overcome some of the obstructive causes (eg, urethrotomy for distal urethral stenosis) but this is uncommon.

• In approximately one half of women, the causes of obstructive voiding dysfunction are previous anti-incontinence surgery and pelvic organ prolapse, which will usually lead to a surgical intervention.

• For men, benign prostate disease is by far the most common cause of obstructive voiding.

ITU recurrente

This is defined as three episodes in 12 months.

• It may benefit from antibiotic prophylaxis. However, there is little evidence to support continuous rather than postcoital dosing.⁷ There is no evidence that rate of recurrence is affected once prophylaxis has stopped.

• Topical oestrogens offer some benefit over placebo in postmenopausal women.⁸

• Cranberry juice may be beneficial in prevention but the evidence is not clear.⁹