Basic Information

Definition

The acute inability to urinate when the bladder is full. This is often, but not always, painful, and the distended bladder may be palpable and percussable. This is distinct from chronic urinary retention, in which patients can still void but chronically retain a significant volume of urine in the bladder after voiding. Chronic urinary retention is not painful.

Synonyms

1. Acute urinary retention (AUR)

2. Urinary retention

3. Retaining urine

Epidemiology & Demographics

Incidence

It is one of the most common urologic emergencies and typically occurs in aging men, especially men older than 60 years. However, it may occur in any age group in either sex. Over a 5-year period, AUR will occur in 10% of men older than 70 years and in one third of men older than 80 years. There is a near linear increase in age-specific incidence for men ages 40 to 80.

Prevalence

40/100,000 in males and 3/100,000 in females. Prevalence has increased with longer average life spans.

Genetics

None known.

Physical Findings & Clinical Presentation

1. Acute inability to pass urine.

2. Pain or pressure in the lower abdomen and suprapubic region is typical, but pain may be absent, especially with older patients, patients with underlying neurologic disorders, and in cases of chronic urinary retention.

3. Palpable and/or percussable bladder may be noted.

4. Suprapubic or bladder tenderness with deep palpation may be elicited.

5. Rarely, flank pain and costovertebral angle tenderness can exist if high bladder pressures are transmitted to the ureters and kidney.

6. Increased severity of lower urinary tract symptoms (LUTS) is associated with increased risk of AUR, and patients may complain of worsening LUTS prior to episode, including increased urinary urgency, incontinence, nocturia, stranguria, hesitancy, and intermittency. These symptoms usually develop between 1 day and a few weeks.

7. Patients with cognitive deficits or inability to communicate may present with restlessness, discomfort, worsened confusion, or delirium and may not be able to provide a history of urinary retention.

8. Acute kidney injury, electrolyte abnormalities, nausea, and lower extremity edema may be present if there is delayed presentation.

Etiology

1. Acute urinary retention may be a spontaneous occurrence or precipitated by a triggering event. Spontaneous AUR may arise from the natural progression of bladder outlet obstruction, more commonly from benign prostatic hyperplasia (BPH) and less commonly from pelvic masses and urethral stricture disease. Conversely, precipitated AUR episodes have an identifiable triggering event, such as acute trauma, surgical procedures (especially spinal, orthopedic, and urologic), medications (e.g., over-the-counter [OTC] antihistamines and sympathomimetic agents commonly found in cough medications, anticholinergic drugs), urinary tract infection, and central nervous system insults (e.g., strokes, hemorrhage). There is overlap between spontaneous and precipitated AUR, particularly when triggering events are superimposed on underlying obstructive risk factors.

2. Mechanistically, urinary retention can result from one of three general categories: (1) Increased bladder outflow obstruction, as seen in BPH, urethral strictures, extrinsic compression from malignancy, constipation, and large clots in hematuric patients that can obstruct the urethra or bladder neck. (2) Disruption in detrusor muscle innervation, such as in diabetic neuropathy, spinal cord injury, progressive neurologic pathologies, as well as bladder contractile dysfunction and decompensation secondary to prolonged outlet obstruction. (3) Bladder overdistension can also lead to impaired contractility, which can result from general anesthesia, epidural anesthesia, or anticholinergic use.

3. Frequently, causes can be multifactorial in older patients, with an underlying obstructive risk factor and an acute precipitant.

4. In women, obstructive factors can include benign tumors (especially fibroids); malignant tumors of pelvic, urethral, or vaginal origin; postpartum vulvar edema; and labial fusion. Pelvic organ prolapse, including cystocele, rectocele, and uterine prolapse, can also lead to urinary retention.

5. Infection such as prostatitis, urethritis, cystitis, genital herpes, and herpes zoster may also produce AUR.

6. Very common in the postoperative period when patients are less mobile, constipated, and using narcotic pain medications, etc.

Differential Diagnosis

1. AUR is typically self-evident to the cognitively intact patient and the treating physician.

2. Chronic urinary retention

3. Occasionally, a pelvic mass, fluid collection, uterine fibroids, pregnancy, or ascites can be confused for a full bladder.

Workup

1. History should focus on urologic symptoms, including dysuria, hematuria, baseline voiding symptoms (caliber of stream, nocturia, sensation of complete emptying, need to double void, incontinence, hesitancy), past episodes of retention, surgical history (both urologic and other surgical procedures, especially if recent), and urologic cancer.

2. History should also include a complete list of prescribed and over-the-counter medications and recent changes in medications.

3. Review of symptoms should include presence of fever, back pain, neurologic symptoms, and rash.

4. Rectal exam for masses, fecal impaction, perineal and perianal sensation, prostate size, and sphincter tone.

5. Genitourinary exam in men, with special attention for meatal stenosis and phimosis or paraphimosis.

6. Pelvic exam in women with attention to any pelvic organ prolapse.

7. Neurologic exam to rule out an underlying neurologic cause.

Laboratory Tests

1. Serum creatinine: In acute retention, level may not be elevated above baseline.

2. Electrolytes, BUN.

3. Urinalysis and culture (obtained via bladder catheterization).

4. Prostate-specific antigen testing is not helpful in AUR and may be falsely elevated after catheter placement. This test should not be checked in the acute setting.

Imaging Studies

1. Bladder ultrasound or a bedside post-void residual urine scan (“bladder scanner”) can be diagnostic. Ascites, pelvic fluid collections, body habitus, and presence of surgical implants (e.g., reservoirs for inflatable penile prostheses or artificial urinary sphincters) may present obstacles to obtaining accurate volume measurement.

2. Abdominal ultrasound or computed tomography (CT) may be helpful if there is suspicion of a pelvic mass.

3. CT (Fig. 1) can be helpful when high volumes are measured by a bedside bladder scan, but low volumes are returned upon bladder catheterization.

   

4. Magnetic resonance imaging (MRI) is used when symptoms suggest spinal cord problems.

5. Renal ultrasound or abdominopelvic CT may be obtained if there is associated renal impairment and hydronephrosis is suspected.

6. Evaluation of bladder function may be considered after initial management, particularly in females with no evidence of anatomic obstruction or in patients with longstanding obstruction or other neurologic conditions that could affect bladder contractility.

Acute General Rx

1. Prompt bladder decompression and drainage is initial management of AUR, usually with an indwelling urethral catheter. Clean intermittent catheterization (CIC) is also an option if the patient possesses the necessary dexterity, vision, and motivation; proper patient technique education can be provided.

2. Consultation with urology is advised when there has been recent genitourinary surgery, a history of urethral stricture disease, or a history of difficult catheterizations.

3. If urethral catheterization is not possible or is contraindicated, suprapubic catheter placement by urology or interventional radiology is necessary.

4. Monitor for post-decompression hematuria, which usually develops shortly after the bladder has been drained and is caused by small vessel injury within the overstretched bladder wall.

5. Monitor for postobstructive diuresis, which can include large volume urine outputs and electrolyte derangements following bladder (and renal) decompression. The danger period typically last 24 to 48 hours.

6. Avoid medications that precipitate AUR (e.g., narcotics, anticholinergics, antihistamines).

Chronic Rx

1. A voiding trial, or “trial of void (TOV)” is reasonable in 5 to 7 days in most patients.

2. α-blockers are effective for treatment of BPH symptoms in men and may increase the success of trials of early catheter removal and should be initiated, unless contraindicated.

3. 5-α reductase inhibitors are not designed for acute management of AUR due to a slower mechanism of action and prostate volume decrease that takes months to realize.

4. Where feasible, medications that increase the risk of AUR should be stopped.

5. Correct constipation and increase patient mobility, as able.

6. If a patient remains unable to void after 5 to 7 days of catheterization, urologic consultation is recommended. Plans to further evaluate the etiology of AUR are critical, including possible cystoscopic evaluation as well as urodynamic studies.

7. Patients unable to void after a voiding trial can either initiate CIC, often every 6 to 8 hours, or have the urinary bladder catheter replaced.

Disposition

1. To home if close follow-up can be ensured and no concerns for acute kidney injury or postobstructive diuresis.

2. Hospital admission may be needed, particularly in patients with sepsis or severe urinary tract infection, acute kidney injury, or electrolyte abnormalities due to retention, or when urinary retention is due to malignancy, hematuria, or spinal cord compression.

Referral

1. Request immediate urologic assistance when attempts at initial bladder catheterization are unsuccessful or when the patient has recently undergone urologic surgery, especially radical prostatectomy, transurethral resection of prostate, urethral stricture surgery, and other bladder/prostate surgeries.

2. Urologic referral is appropriate for almost all cases, but it can be completed either after a successful voiding trial or after the catheter has been in a few days. This allows the urologist to perform the voiding trial and/or to assess baseline voiding function. Recurrent episodes of retention in men warrant urologic referral to determine the cause for retention. In cases of obstruction, surgical intervention such as transurethral resection of prostate, laser prostatic treatments, or simple prostatectomy may be required.

3. Gynecologic referral is mandatory if a pelvic mass is found to be the cause of AUR in a woman.

1. AUR is often painful and can cause distress

2. Rapid bladder drainage is of paramount importance

3. Monitor for postobstructive diuresis and correct electrolyte abnormalities

4. Request urology advice or referral for AUR following urologic surgery

Prevention

Patients with BPH should be cautious regarding the use of medications that can precipitate acute retention, including antihistamines, sympathomimetics, sedatives, and anticholinergics.

• C. Halbgewachs, T. Domes: Postobstructive diuresis: pay close attention to urinary retention. Can Fam Physician. 61 (2):137–142 2015 25821871

• J.R. Marshall, J. Haber, E.B. Josephson: An evidence-based approach to emergency department management of acute urinary retention. Emerg Med Pract. 16 (1):1 2014

• A. Mevcha, M.J. Drake: Etiology and management of urinary retention in women. Indian J Urol. 26 (2):230–235 2010 20877602

• M. Oelke, M.J. Speakman, F. Desgrandchamps, et al.: Acute urinary retention rates in the general male population and in adult men with urinary tract symptoms participating in pharmacotherapy trials: a literature review. Urology. 86 (4):645–665 2015

• A. Sliwinski, F.T. D’Arcy, R. Sultana, et al.: Acute urinary retention and the difficult catheterization: current emergency management. Eur J Emerg Med. 23:80–88 2016 26479738

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1. Benign Prostatic Hyperplasia (Related Key Topic)