Urinary Retention: Pathophysiology, Clinical Imaging Features, and Evidence-Based Management

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 Introduction

Urinary retention is a urological condition characterized by the inability to voluntarily empty the bladder completely. 

It represents a significant cause of morbidity across diverse populations and remains a clinical entity of high relevance in both acute and chronic settings. 

With the aging global population and the rising prevalence of comorbid conditions such as diabetes mellitus and neurological disorders, urinary retention continues to be a crucial area of research and clinical focus.

In this comprehensive column, we will review the pathophysiology, epidemiology, clinical presentation, imaging findings, differential diagnosis, diagnostic strategies, treatment modalities, and prognosis of urinary retention.  

The discussion will integrate state-of-the-art imaging features illustrated by clinical cases, including CT and ultrasound, provided in the case review file. 

1. Pathophysiology of Urinary Retention

Urinary retention occurs when there is impaired coordination between the bladder detrusor muscle and the urinary sphincter, or when there is physical obstruction to urinary outflow. Pathophysiological mechanisms can be broadly divided into:

  • Obstructive causes:

    • Benign prostatic hyperplasia (BPH) in men, which remains the leading cause.

    • Urethral stricture, bladder calculi, pelvic tumors, or external compression (e.g., large uterine fibroids).

  • Neurogenic dysfunction:

    • Neurological disorders such as multiple sclerosis, spinal cord injury, stroke, Parkinson’s disease, and diabetic neuropathy disrupt detrusor-sphincter synergy.

  • Myogenic failure:

    • Long-standing bladder overdistension can cause detrusor underactivity.

  • Pharmacologic factors:

    • Anticholinergics, opioids, and certain antidepressants interfere with bladder contractility or neural signaling.

Ultimately, retention may manifest acutely, requiring urgent decompression, or chronically, leading to progressive bladder remodeling and upper urinary tract damage.

2. Epidemiology

The epidemiology of urinary retention reflects a striking gender disparity.

  • Men: Acute urinary retention (AUR) is far more common, with lifetime risk estimated at 23–30% among men in their 70s–80s, primarily due to prostatic enlargement.

  • Women: Although less frequent, female urinary retention can be associated with pelvic organ prolapse, gynecological surgery, and neurologic disorders.

  • Chronic urinary retention (CUR): More insidious in presentation, prevalence estimates range from 3–7 per 100,000 individuals annually, though underdiagnosis is likely.

Aging, polypharmacy, and neurological comorbidities collectively increase the incidence worldwide.

3. Clinical Presentation

Typical clinical manifestations include:

  • Difficulty initiating urination

  • Weak or intermittent urinary stream

  • Sensation of incomplete emptying

  • Suprapubic fullness or pelvic pain

  • Overflow incontinence in chronic cases

  • In severe cases, acute renal impairment due to obstructive uropathy

4. Imaging Features

Imaging plays a vital role in confirming urinary retention and identifying its cause.

Figure 1. Axial CT of the pelvis;  Axial CT demonstrating a markedly distended urinary bladder with mass effect on adjacent pelvic structures. This imaging is consistent with urinary retention.

Figure 2. (A) Sagittal CT, (B) Ultrasound, (C) Axial CT;  (A) Sagittal CT reveals bladder overdistension extending into the pelvis. (B) Ultrasound shows an anechoic fluid-filled bladder with post-void residual volume. (C) Axial CT again highlights urinary bladder enlargement with upstream hydronephrosis. These findings corroborate the diagnosis of urinary retention.

5. Differential Diagnosis

When evaluating imaging findings of a pelvic mass or suprapubic distension, differential diagnoses include:

  • Uterine fibroid

  • Ovarian cyst

  • Pelvic teratoma

  • Abdominal aortic aneurysm

  • Ascites

Correlation with clinical presentation and targeted imaging (e.g., bladder scanning) is essential for accurate diagnosis.

6. Diagnostic Workup

  • Clinical evaluation: Detailed history (voiding patterns, medications, neurologic history) and physical examination (digital rectal exam for prostate assessment).

  • Bladder scanning: Post-void residual volume >300 mL strongly suggests retention.

  • Laboratory tests: Serum creatinine, urinalysis to assess renal involvement and infection.

  • Imaging: Ultrasound and CT remain pivotal in complex or atypical cases.

7. Treatment

Acute urinary retention:

  • Immediate bladder decompression via urethral or suprapubic catheterization.

  • Pharmacologic management with alpha-adrenergic antagonists in men with BPH.

  • Address precipitating medications.

Chronic urinary retention:

  • Intermittent self-catheterization remains the standard of care.

  • Surgical interventions: TURP (transurethral resection of the prostate), urethral dilation, or correction of pelvic organ prolapse.

  • Neuromodulation or botulinum toxin injection for refractory neurogenic retention.

8. Prognosis

  • Acute urinary retention: With timely decompression, outcomes are favorable, though recurrence is common if underlying pathology is untreated.

  • Chronic urinary retention: Carries risks of recurrent urinary tract infection, bladder calculi, hydronephrosis, and chronic kidney disease.

  • Prognosis depends on etiology, timeliness of treatment, and comorbidity profile.

Quiz

Q 1: A 70-year-old male presents with lower extremity edema and suprapubic pain. Pelvic CT shows a massively distended bladder. Which of the following is the most likely diagnosis?

  1. Uterine fibroid

  2. Ovarian cyst

  3. Urinary retention

  4. Teratoma

  5. Abdominal aortic aneurysm

Q 2: Which of the following is NOT a typical cause of urinary retention?

  1. Benign prostatic hyperplasia

  2. Urethral stricture

  3. Anticholinergic medication use

  4. Diabetes-induced neuropathy

  5. Hyperthyroidism

Q 3: In chronic urinary retention, which of the following is the most appropriate long-term management strategy?

  1. Immediate suprapubic catheterization

  2. Intermittent self-catheterization

  3. Single-dose antibiotics

  4. Observation only

  5. Intravenous hydration

Answer & Explanation

1. Answer: 3. Urinary retention. Explanation: The CT demonstrates classic findings of a distended urinary bladder, consistent with urinary retention.

2. Answer: 5. Hyperthyroidism. Explanation: Hyperthyroidism is not directly associated with urinary retention, unlike BPH, strictures, medications, and neuropathy.

3. Answer: 2. Intermittent self-catheterization. Explanation: Intermittent catheterization reduces complications compared to indwelling catheters and is the preferred management for chronic urinary retention.

References

  1. D. Kaplan, "Urinary retention: Pathophysiology and management," The New England Journal of Medicine, vol. 388, no. 15, pp. 1423–1435, 2023.

  2. S. Gratzke et al., "Management of male lower urinary tract symptoms: EAU Guidelines," European Urology, vol. 79, no. 3, pp. 387–398, 2021.

  3. A. J. Wein, L. R. Kavoussi, A. W. Partin, and C. A. Peters, Campbell-Walsh Urology, 12th ed., Elsevier, 2020.

  4. D. R. Boone et al., "Chronic urinary retention: Current perspectives and future directions," Nature Reviews Urology, vol. 19, no. 4, pp. 203–215, 2022.

  5. J. T. Stoffel, "Neurogenic bladder and urinary retention: Modern approaches," Current Opinion in Urology, vol. 32, no. 2, pp. 125–132, 2022.

  6. A. C. Thorpe and J. Neal, "Acute urinary retention in men: An age old problem," BMJ, vol. 376, pp. e068943, 2022.

  7. P. Abrams et al., "The standardisation of terminology in lower urinary tract function," Neurourology and Urodynamics, vol. 40, no. 1, pp. 33–49, 2021.

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