The history of the patient presenting with symptoms of acute urinary retention should focus on lower urinary tract symptoms using questions such as, "Over the past month:"

1. How frequently have you had the sensation of not being able to empty your bladder completely after voiding?

2. How frequently have you had to urinate again less than two hours after finished urinating?

3. How frequently have you found you stopped and started several times when you were voiding?

4. How often have you have found it difficult to postpone urination?

5. Over the past month, how often have you had a weak stream? 

6. How often have you had to push or strain to begin urination?

7. How many times did you get up to urinate from the time you go to bed until you get up in the morning? 

 The American Urological Association developed a scoring system using these question using a rating scale:

• Not at all=0
• Less than 1 time in 5 = 1
• Less than half the time = 2
• About half the time = 3
• More than half the time = 4
• Almost always = 5

This scoring system helps identify mild symptoms (0 to 7), moderate symptoms (8 to 19), and severe symptoms (20 to 35) related to the prostate as a cause.[13][14][20][21]

The clinician should inquire about the history of prostate diseases such as cancer, trauma, surgery, kidney stones, prostate infections, sexually transmitted infections, radiation treatment or exposure, and back pain. History on the presence of hematuria, dysuria, fever, low back pain, neurologic symptoms of tremors, weakness is vital. A thorough urogenital review of systems is a must. The medication list should undergo thorough review as several medications can cause urinary retention, and inquiry into past surgical procedures, and anesthesia may also prove informative.[22]

The physical examination should focus on the lower quadrants of the abdomen, pelvis, and genitals. Palpation can often note the distended bladder; the rectal exam can note an enlarged prostate (showing prostatic hyperplasia) or fecal impaction (showing impingement on the bladder neck or urethra), or poor sphincter tone (showing a spinal cord problem). Neurologic examination for strength, sensation, reflexes, and muscle tone is also informative. Thorough patient history and physical exam will often identify the etiology.[23][24][25]

The evaluation should consist of: [19][20][26][1][23][27]

• A urine sample obtained by having the patient void on their own and checking pre and post-void residuals with a bladder scanner, or placement of a Foley catheter
• Chemistries: sodium, potassium, bicarbonate, chloride, blood urea nitrogen and creatinine
• A complete blood count
• If neurologic signs and symptoms are present on examination and there is suspicion of stroke, CT of the head
• If spinal cord processes are suspected, MRI
• Evaluation by urology and other appropriate specialists to aid in the diagnosis of the etiology will proceed based on the findings of the history and physical

Diagnosis:

The diagnosis of acute urinary retention is aided by bladder ultrasound, but catheterization is reasonable as it is both diagnostic and therapeutic.  The bladder ultrasound that suggests a volume greater than or equal to 300 mL in a patient unable to void suggests urinary retention.  Bladder ultrasound can be inaccurate because of body habitus, tissue edema, prior surgery, and scarring. The placement of a catheter might be needed. The volume of urine obtained from drainage in the first 10 to 15 minutes should be recorded. If the volume exceeds 400 mL, the catheter will typically remain in place. For volumes of 200 to 400 mL, the decision to leave the catheter in place is guided by the clinical scenario as volumes less than 200 mL likely do not have acute urinary retention and should undergo evaluation for other causes of abdominal or suprapubic discomfort.[28][29][30][31]

The following outlines treatment of lower outlet tract obstruction, prostatic, and urethral causes:

As the patient with acute urinary retention is in discomfort, placement of a urinary catheter or suprapubic catheter (if the urethra is not accessible) should be done to decompress the bladder and relieve the lower tract obstruction.  Urethral catheterization is particularly useful in patients where the cause of urinary retention is temporary, such as infection or medication.  Urethral catheterization is contraindicated in patients with recent urologic surgery such as radical prostatectomy or urethral reconstruction. These patients should have suprapubic catheterization (SPC). 

The urethral catheter should be 16 to 18 French as first-line therapy. If one suspects an enlarged prostate as the cause of the obstruction, then they may need a larger 20 to 22 French gauge catheter with a firm coude tip.  If stricture or prostatic scar is a concern, a smaller catheter 10 to 12 French may be an option.  If failure to pass the catheter happens, then urologic consultation may be required. The urologist may be able to perform bedside flexible cystoscopy with either dilatation of the stricture or passage of wire over which one may place a urinary catheter.[32]

After initial decompression with a catheter, discussion with the patient to perform a clean intermittent catheterization versus short-term placement of a catheter with a later trial without catheterization. There are fewer complications with clean intermittent catheterization, and it correlates with an increased rate of spontaneous voiding and a reduction in urinary tract infections. Clean intermittent catheterization is often more acceptable to the patient if the nursing staff focuses on good instruction and placement of the catheter. Further outpatient support services may help. Patients are usually receptive to education.[33]

Treatment of those with nontemporary (chronic) etiology of urinary retention: neurogenic, spinal, demyelination, and contraindication to Foley catheter placement

For patients who had to have a suprapubic catheter due to contraindications or failed urethral catheterization, the urologist usually places suprapubic catheters, but in emergent conditions where a urologist is not present, and the patient is in distress, suprapubic aspiration via a needle is an option. This procedure is performable with ultrasound guidance at the bedside. Some studies show patients with suprapubic catheters experience less discomfort. Placement of suprapubic catheters is not without risk, as bowel perforation and wound infection are possible.[34]

The rate of bladder decompression through studies have shown that rapid, complete drainage is best. Clamping and partial drainage do not reduce the complications of hematuria, hypotension, and post-obstructive diuresis. The studies also showed that partial drainage and clamping increased the risk of urinary infection.[22][24][17]

Overview of catheterization treatment:

The underlying etiology determines the duration of catheterization. In the patients where the underlying etiology is temporary, such as with medications or anesthetic should have a post-voiding trial as soon as possible, within 2 to 3 days. In patients with a spinal injury where urinary retention is not likely to resolve, catheterization may become chronic.  These patients are candidates for clean intermittent catheterization or suprapubic catheterization.[2]

The underlying etiology, such as infection, should receive treatment. Medications causing urinary retention should be stopped.  Benign prostatic hyperplasia should receive medical treatment and evaluation for surgical intervention such as transurethral resection.[17]

Patients who have urosepsis, have obstruction due to malignancy, or acute myelopathy should be admitted. [17] Patients who have associated acute renal failure or electrolyte imbalance such as hypernatremia or hyponatremia should also be admitted. [25][17]

Most cases of acute urinary retention will be managed safely outpatient with a referral for further evaluation of etiology if not identified in the emergent setting.  Patients discharged need instruction in catheterization for intermittent catheterization, Foley catheter care, how to empty catheter bag, and monitoring their urine output.  Patients should not be placed on antibiotics unless a urinary infection is present. Prophylactic antibiotics have been shown not to prevent infection and may increase resistance.[25][17]

Benign prostatic hyperplasia (BPH) is the most common etiology in men, especially over the age of 60; therefore, a focus of the treatment is medicine and referral to urology for further evaluation of the need for surgical treatment.  Medical treatment of BPH includes an alpha-1 adrenergic antagonist (alfuzosin 10 mg or tamsulosin 0.1 mg). Alpha-1 adrenergic antagonists work by relaxing the smooth muscle at the bladder neck and the capsule of the prostate. Other medications, such as 5-alpha reductase inhibitors, decrease the incidence of acute urinary retention in men with BPH. Patients need to be treated over one year to prevent acute urinary retention and reduce the need for surgery. Trial without catheter should be tried twice before considering surgical therapy. The studies have shown increased success with patients with following characteristics, age less than 65, detrusor pressure greater than 35 cm water, a drained volume of less than one liter at catheterization, and the identification of the precipitating event.[35][36]

The duration of catheterization in men with BPH should not be over seven days. There has been a large observational study in which patients with medical treatment showed greater success with spontaneous voiding with catheterization of 3 days or fewer. For those men who have BPH and fail a second trial without a catheter, transurethral resection of the prostate (TURP) reduces the risk of developing acute urinary retention 85 to 90 percent.  The timing of surgery is to wait 30 days from the episode of acute urinary retention. Urologists usually perform urodynamic studies to assure the retention is directly related to outlet obstruction.[37]

As discussed under etiologies, the differential diagnosis for an acute urinary retention event is wide, with the most common in men over 65 is BPH. Other causes of the event include medications, anesthetics, surgical procedures, nerve injury, spinal cord injury, stroke, demyelinating diseases, infection bacteria and viral (herpes simplex, herpes zoster), stricture, scaring, and trauma. History and review of systems are the primary way to identify the cause followed by a physical exam with a thorough neurologic examination.  Laboratory evaluation for associated complications of infection, renal dysfunction, and electrolyte imbalance is necessary.  Further diagnostic testing should proceed based on the findings of the history and physical to evaluate for infection, stroke, and spinal cord diseases. [38][39]

Men with BPH who develop acute urinary retention are usually greater than 70, with more comorbidities and have a higher risk of complications. These comorbidities include infection and renal dysfunction, such as chronic kidney disease (CKD) and end-stage renal disease (ESRD).[40] The prognosis is determined by response to therapy. Studies have shown that transurethral resection reduces acute urinary retention by 85 to 90 percent.  Patients who undergo immediate surgery following an episode of acute urinary retention are at increased risk of complications, including operative bleeding and sepsis from bacteriuria. Men who underwent prostatectomy for acute urinary retention had increased risk of death at 30 and 90 days compared to men who underwent elective prostatectomy.  The older the patient, the higher the risk of complications. Those with other causes of acute urinary retention from neurologic conditions are at increased risk from infection and sequelae of the underlying disease.  Acute urinary retention due to temporary causes has a better prognosis than those that are due to long-term or chronic disease because of associated complications with long-term catheterization.  The use of modalities of intermittent catheterization and suprapubic catheterization has been shown to result in fewer complications.[41][35][17][42]

As stated in previous sections, complications from acute urinary retention are from the underlying causes and treatments. They include infection, renal dysfunction, electrolyte imbalances, stricture of the urethra, bladder neck dilation, and detrusor muscle dysfunction. The treatment via catheterization for bladder decompression can result in adverse events such as hematuria, which occurs between 2 to 16 percent of the patients but is rarely significant. This complication usually resolves with irrigation.[35] Transient hypotension is a complication that occurs after initial bladder decompensation, but it is transient, and blood pressure normalizes without intervention. Post obstructive diuresis may persist after decompression of the bladder. This primarily occurs with chronic urinary retention and usually represents an appropriate attempt to excrete excess fluid retained during the period of obstruction. This situation is managed by increasing oral fluid intake unless the patient is unable.  If intravenous fluid replacement is needed, replacement is guided by a measure of urine output, replacing one half the urine volume with isotonic saline. The replacement fluid can be different depending on the presence of hypernatremia or hyponatremia.[43][44][27]

• Nephrology
• Pediatric nephrology
• Urology
• Pediatric urology

The patient with acute urinary retention needs to be educated about catheter care and monitoring urinary output. If the patient is performing clean intermittent catheterization, they need to be taught proper techniques to avoid complications. Those with suprapubic catheters need to be shown proper care of these catheters and keeping the suprapubic site clean and free of the urinary leak to prevent dermatitis.  Patients may need followup home care and education if they have complications. The patient with benign prostatic hyperplasia requires education about the trial without catheterization and follow-up care. The surgical options and the risk and complications of surgical treatment should be shared with the patient. If the etiology of the acute urinary retention is medication-based, the patient should understand the side effects of the medication and the need to find an alternative. 

The health outcomes can be enhanced by a thorough history using the questions suggested by the American Urological Association. One needs to obtain a medication review and perform a thorough physical examination to rule out a neurological disorder. Patients should receive counseling about catheter care and the importance of antisepsis.  The nursing team needs to know of contraindications of catheter placement and be able to recognize them.  Timely, urologic consultation for suprapubic catheterization is the recommendation in patients who have acute retention and inability to pass a urethral catheter. The clinician needs to be knowledgeable of how to do suprapubic needle drainage or temporary catheter drainage if the patient is in extreme discomfort or distress when a urologist is not immediately available. 

The patient and patient’s support (family or caregivers) should receive training regarding clean intermittent catheterization, as well as education on medications used to treat benign prostatic hyperplasia.  

Coordination between primary care clinicians, nephrologists, urologists, and emergency room clinicians is needed. Urology nurses educate patients, monitor their condition and provide update information to the interprofessional team. Pharmacists assess medications, monitor compliance, and inform patients about the side effects of medications. [Level 5]