Urinary retention


Refers to the inability to completely empty the bladder.

Onset can be sudden or gradual.

Acute urinary retention is a medical emergency.

When UR Is of sudden onset, symptoms include an inability to urinate and lower abdominal pain.

When URB is of gradual onset, symptoms may include loss of bladder control, mild lower abdominal pain, and a weak urine stream.

Those with long term problems are at risk of urinary tract infections. frequent urination, loss of bladder control,

Causes include lockage of the urethra, nerve problems, certain medications, and weak bladder muscles.

Treatment is by catheter, urethral dilation, urethral stents and surgery.

Medication treatment includes Alpha blockers such as terazosin, 5α-reductase inhibitors such as finasteride.

6 per 1,000 per year in males > 40 years old.

Causes include blockage of the urethra, nerve problems, medications, and weak bladder muscles.

Blockage can be caused by benign prostatic hyperplasia (BPH), urethral strictures, bladder stones, a cystocele, constipation, or tumors.

Nerve problems can occur from diabetes, trauma, spinal cord problems, stroke, or heavy metal poisoning.

Medications that can cause problems include anticholinergics, antihistamines, tricyclic antidepressants, decongestants, cyclobenzaprine, diazepam, NSAIDs, amphetamines, and opioids.

Diagnosis is typically based on measuring the amount of urine in the bladder after urinating.

Treatment is typically with a catheter either through the urethra or lower abdomen.

Other treatments may include medication to decrease the size of the prostate, urethral dilation, a urethral stent, or surgery.

Males are more often affected than females.

In males over the age of 40 about 6 per 1,000 are affected a year.

Among males over 80 this increases 30%.

Urinary retention is characterised by poor urinary stream with intermittent flow, straining, a sense of incomplete voiding, and hesitancy.

If the bladder remains full, it may lead to incontinence, nocturia and high frequency.

Acute retention, causing complete anuria, is a medical emergency, as the bladder can stretch to an enormous size, and possibly tear if not dealt with quickly.

If the bladder distends enough, it becomes painful, which may be suprapubic, constant, and dull.

The increase in bladder pressure can also prevent urine from entering the ureters or cause urine to pass back up the ureters and get into the kidneys, causing hydronephrosis, and possibly pyonephrosis, kidney failure, and sepsis.

Neurogenic bladder can be caused pelvic splanchic nerve damage, cauda equina syndrome, descending cortical fibers lesion, pontine micturition or storage center lesions, demyelinating diseases or Parkinson’s disease.

Iatrogenic causes by medical treatment/procedure include: scarring of the bladder neck from removal of indwelling catheters or cystoscopy.

Obstruction in the urethra by injury.

Risk factors include:

Age: Older people may have degeneration of neural pathways involved with bladder function and it can lead to an increased risk of postoperative urinary retention.

The risk of postoperative urinary retention increases up to 2 fold for people older than 60 years.

Medications: Anticholinergics and medications with anticholinergic properties, alpha-adrenergic agonists, opiates, nonsteroidal anti-inflammatories (NSAIDs), calcium-channel blockers and beta-adrenergic agonists, may increase the risk.

Anesthesia: General anesthetics during surgery may cause bladder atony by acting as a smooth muscle relaxant, and can directly interfere with autonomic regulation of detrusor tone and predispose to bladder overdistention and retention.

Spinal anesthesia results in a blockade of the micturition reflex, and has a higher risk of postoperative urinary retention compared to general anesthesia.

Benign prostatic hyperplasia:

Operative times longer than 2 hours may lead to an increased risk of postoperative urinary retention.

Chronic urinary retention due to bladder blockage can either be as a result of muscle damage or neurological damage.

Neurological damage, causing a disconnect between the brain to muscle communication, can make it impossible to completely empty the bladder.

If the retention is due to muscle damage, muscles may not able to contract enough to completely empty the bladder.

Most common cause of chronic urinary retention is BPH.

The prostate has constant growth due to the conversion of testosterone to dihydrotestosterone, and can cause the prostate to push on the urethra,which can lead to urinary retention.

Other causes of urinary retention includes:

Psychogenic causes

consumption of some psychoactive substances

NSAIDs with anticholinergic properties.

To establish the type of urination abnormality, ultrasound of the bladder may show a slow rate of flow, intermittent flow, or a large amount of urine retained in the bladder after urination.

A normal flow study should be 20-25 mL/s peak flow rate, and a post-void residual urine greater than 50 ml is a significant amount of urine and increases the potential for recurring urinary tract infections.

Due to decreased contractility of the detrusor muscle, adults older than 60 years, 50-100 ml of residual urine may remain after each voiding.

The normal capacity of the bladder is 400-600 ml.

In chronic urinary retention, there may be a massive increase in bladder capacity.

The diagnosis of urinary retention is confirmed over a period of 6 months, with 2 separate measurements of urine volume 6 months apart, with PVR (post-void residual) volume of >300mL.

The inability to pass urine often arises without warning.

In some patients it starts gradually.

Associated pain can be excruciating with urinary retention.

Urinary intention may be associated with sweating, chest pain, anxiety, high blood pressure, and a shock-like condition.

Serious complications of untreated urinary retention include bladder damage and kidney failure.

It is treated in a hospital setting.

The earlier one seeks treatment, the fewer the complications.

Obstruction of the urinary tract may cause:

Bladder stones

Atrophy of the detrusor muscle


Hypertrophy of the detrusor muscle

Diverticula in the bladder wall.

In acute urinary retention, urinary catheterization, placement of a prostatic stent, or suprapubic cystostomy relieves the retention.

BPH may respond to alpha blocker and 5-alpha-reductase inhibitor therapy, or surgically with prostatectomy or transurethral resection of the prostate.

BPH treatment with medications include.: tamsulosin to relax smooth muscles in the bladder neck, and finasteride and dutasteride to decrease prostate enlargement.

Acute urinary retention is treated by placement of a urinary catheter into the bladder.

The catheterization can be intermittent or a placement of a Foley catheter, which is long-lasting.

Patients can perform clean intermittent self catheterization.

Self catheterization technique reduces the rate of infection from long-term Foley catheters.

Self catheterization requires doing the procedure every 3 or 4 hours 4-6 times a day.

Chronic form of urinary retention may require some type of surgical procedure.

Most patients with BPH may benefit from s transurethral resection of the prostate (TURP) to relieve bladder obstruction.

Incidence of postoperative urinary retention for TURP IS 4.7%.

In males with lower urinary tract symptoms, the sitting position is associated with reduced residual urine in the bladder, while the maximum urinary flow and the voiding time are increased and decreased respectively.

For healthy males, no influence was found on these parameters, meaning that they can urinate in either position.

A meta-analysis summarizing the evidence found no superior position for young, healthy males, but for elderly males with lower urinary tract symptoms the sitting position compared to the standing:

the post void residual volume (PVR, ml) was significantly decreased

the maximum urinary flow (Qmax, ml/s) was increased

the voiding time (VT, s) was decreased

it is a common disorder in elderly males.

The most common cause of urinary retention is BPH.

BPH starts around age 50 and symptoms may appear after 10–15 years.

BPH is a progressive disorder and narrows the neck of the bladder leading to urinary retention.

By the age of 70, almost 10 percent of males have some degree of BPH and 33% have it by the eighth decade of life.

BPH rarely causes sudden urinary retention.

BPH can become acute process in the presence of certain medications such as blood pressure pills, anti histamines, antiparkinson medications, and after anaesthesia or stroke.

The most common cause of urinary retention in young men is infection of the prostate, that is, acute prostatitis.

Acute prostatitis is an infection acquired during sexual intercourse and presents with low back pain, penile discharge, low grade fever and an inability to pass urine.

Approximately 1-3 percent of males under the age of 40 develop urinary difficulty as a result of acute prostatitis.

Cancers of the bladder, prostate or ureters can gradually obstruct urine output.

Urinary retention in females is uncommon.

Urinary retenion occurs in females 1 in 100,000 every year.

The female-to-male incidence rate of urinary retention is 1:13.

Urinalysis retention in females is usually transient, and can occur postoperatively and postpartum.

Urethral catherization in women usually resolves the problem.

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