The causes of Urinary bladder retention can be understood by broadly understanding it into two simplest terms- Urinary tract blockage and Neurological causes. We will elaborate and simplify the causes of urinary retention under these two words as follows:

What is Urinary Retention?

Urinary retention is the inability to urinate, thereby the bladder doesn’t empty. It could be acute or chronic retention of urine. Acute Urinary Retention is a medical emergency and needs to be treated with foley’s catheter most often.

Causes

Following are broad causes of Urinary Retention in males:

Cause Men
Obstructive Benign prostatic hyperplasia; meatal stenosis; paraphimosis; penile constricting bands; phimosis; prostate cancer
Infectious and inflammatory Balanitis; prostatic abscess; prostatitis
Other Penile trauma, fracture, or laceration

Urinary Tract Blockage

Rewind back a bit, what are components of Urinary tract?

Now, if Urinary bladder can be compressed by many adjacent structures, so the following causes urinary retention in males:

  • Benign prostate hyperplasia (most common in men with age group of 50-60 years)
  • Nephrolithissis or renal stones or kidney stones
  • Urethral Stricture (narrowing)
  • Weak bladder muscle
  • Prostate carcinoma
  • Bladder diverticula
  • Infections causing swelling of adjacent structures- Prostatitis, Cystitis

Neurological causes

The bladder sends a signal to brain, telling it to empty urinary bladder. What if brain doesn’t gets these signals or is unable to manipulate them? The bladder will keep filling and the brain will not understand if it’s full or not, resulting in Urinary retention, right?

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Following are neurological causes of Urinary Retention:

Lesion Type Causes
Autonomic or peripheral nerve Autonomic neuropathy; diabetes mellitus; Guillain-Barré syndrome; herpes zoster virus; Lyme disease; pernicious anemia; poliomyelitis; radical pelvic surgery; sacral agenesis; spinal cord trauma; tabes dorsalis
Brain Cerebrovascular disease; concussion; multiple sclerosis; neoplasm or tumor; normal pressure hydrocephalus; Parkinson’s disease; Shy-Drager syndrome
Spinal cord Dysraphic lesions; invertebral disk disease; meningomyelocele; multiple sclerosis; spina bifida occulta; spinal cord hematoma or abscess; spinal cord trauma; spinal stenosis; spinovascular disease; transverse myelitis; tumors or masses of conus medullaris or cauda equine

Clinical Approach

Although history taking is the first step to approaching the patient with urinary retention, physical examination should be done carefully to predict the correct diagnosis. Following are the points of History, Physical Examination and Possible Etiology in male patients with urinary retention:

History Physical examination Possible etiology
Previous history of urinary retention Enlarged, firm, nontender, nonnodular prostate on digital rectal examination; prostate examination may be normal Benign prostatic hyperplasia
Fever; dysuria; back, perineal, rectal pain Tender, warm, boggy prostate; possible penile discharge Acute prostatitis
Weight loss; constitutional signs and symptoms Enlarged nodular prostate; prostate examination may be normal Prostate cancer
Pain; swelling of foreskin or penis Edema of penis with non-retractable foreskin; externally applied penile device Phimosis, paraphimosis, or edema caused by externally placed constricting device

Diagnosis

Lab tests involve Urinalysis, Serum BUN and creatinine, RBS (random blood sugar>125) for diabetes mellitus and prostate-specific antigen for ruling out prostate cancer.

Imaging studies include USG (ultrasound) of pelvis, KUB (Kidney Urinary Bladder) CT Scan of Abdomen and pelvis, and Brain & Spine with MRI. Blood tests may be evaluated as well. Following are tests done for diagnosing Urinary Retention in males:

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Test type Diagnostic test Rationale
Laboratory Urinalysis Evaluate for infection, hematuria, proteinuria, glucosuria
Serum blood urea nitrogen, creatinine, electrolytes Evaluate for renal failure from lower urinary tract obstruction
Serum blood glucose Evaluate for undiagnosed or uncontrolled diabetes mellitus in neurogenic bladder
Prostate-specific antigen Elevated in prostate cancer; may be elevated in benign prostatic hyperplasia, prostatitis, and in the setting of acute urinary retention
Imaging studies Renal and bladder ultrasonography Measure post-void residual urine; evaluate for bladder and urethral stones, hydronephrosis, and upper urinary tract disease
Pelvic ultrasonography; CT of abdomen and pelvis Evaluate for suspected pelvic, abdominal, or retroperitoneal mass or malignancy causing extrinsic bladder neck compression
MRI or CT of brain Evaluate for intracranial lesion, including tumor, stroke, multiple sclerosis (MRI preferred in multiple sclerosis)
MRI of spine Evaluate for lumbosacral disk herniation, cauda equina syndrome, spinal tumors, spinal cord compression, multiple sclerosis
Other Cystoscopy, retrograde cystourethrography Evaluate for suspected bladder tumor and bladder or urethral stones or strictures
Urodynamic studies (e.g., uroflowmetry, cystometry, electromyography, urethral pressure profile, video urodynamics, pressure flow studies of micturition) Evaluate bladder function (detrusor muscle and sphincter) in patients with neurogenic bladder to help guide management

Management

Initial management involves catheterization with Foley’s catheter. However, if urethral catheterization is unsuccessful or contraindicated, Supra-Pubic catheterization is the choice. The aim is to decompress the bladder before more damage occurs. Thus, emptying of bladder with urine bags is the first line of treatment in Acute Urinary Retention.

Next step is to establish the diagnosis with the proper lab tests and imaging. Correct history and physical examination also helps in establishing the diagnosis of retention of urine.

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Additionally, symptomatic treatment may be given to control the exaggerated symptoms in the patient and provide relief from the severe pain of stretching bladder.

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