What causes post coital urinary retention?

Post-Coital Urinary Retention: Causes and Mechanisms

Post-coital urinary retention is not a recognized clinical entity in the medical literature, and the provided evidence does not identify sexual intercourse as a direct cause of urinary retention. However, understanding the mechanisms and risk factors for urinary retention in general can help clarify why this condition might occur in temporal association with sexual activity.

Primary Causes of Urinary Retention

The most common causes of urinary retention are obstructive in nature, with the following distribution 1, 2:

• Benign prostatic hyperplasia (BPH) accounts for 53% of cases in men 1
• Infectious and inflammatory conditions including prostatitis, cystitis, urethritis, and vulvovaginitis 2
• Pharmacologic causes from anticholinergic medications and alpha-adrenergic agonists 2, 3
• Neurologic causes from cortical, spinal, or peripheral nerve lesions 2
• Obstructive causes in women often involve pelvic organs 2

Potential Mechanisms for Post-Coital Urinary Retention

While not explicitly documented as "post-coital urinary retention," several mechanisms could explain urinary retention occurring after sexual activity:

Anatomical and Mechanical Factors

• Pelvic organ prolapse or cystocele in women can worsen with increased intra-abdominal pressure during intercourse, potentially causing temporary obstruction 4
• Urethral trauma or inflammation from sexual activity, particularly in the setting of pre-existing urethritis or vulvovaginitis 2
• Prostatic inflammation that may be exacerbated by sexual activity in men with underlying prostatitis 2

Pharmacologic Contributions

Medications with anticholinergic or alpha-adrenergic properties are well-established causes of urinary retention 2, 3:

• Anticholinergic drugs (antipsychotics, antidepressants, antihistamines) 3
• Alpha-adrenergic agonists (decongestants, sympathomimetics) 3
• Opioids and benzodiazepines 3
• NSAIDs, calcium channel antagonists, and detrusor relaxants 3

Up to 10% of urinary retention episodes may be attributable to concomitant medication use 3, and these effects could be unmasked or worsened by the physiologic changes during sexual activity.

Neurologic and Functional Factors

• Temporary autonomic dysfunction related to the sympathetic activation during sexual arousal and orgasm could theoretically impair detrusor contractility 2
• Pre-existing neurogenic bladder conditions may become symptomatic after the bladder fills during prolonged sexual activity 2, 5

Risk Factors for Urinary Retention

Elderly patients are at significantly higher risk due to 3:

• Co-existing BPH in men 1
• Multiple medications that impair micturition 3
• Age-related changes in bladder function 5

Women with specific risk factors including 4:

• Urinary incontinence and high post-void residual volumes 4
• Cystocele or pelvic organ prolapse 4
• History of pelvic surgery, particularly rectal/pelvic procedures 4
• Large pelvic tumors or neoadjuvant therapy 4

Clinical Evaluation

Initial assessment should measure post-void residual (PVR) volume 1, 2:

• Acute urinary retention: No consensus PVR definition, but typically presents with inability to void despite full bladder 1
• Chronic urinary retention: PVR >300 mL on two separate occasions persisting for at least 6 months 1

Key history elements to obtain 1, 2:

• Complete medication list including over-the-counter drugs and herbal supplements 1
• Symptoms of prostatism in men (hesitancy, weak stream, incomplete emptying) 2
• Symptoms of pelvic organ prolapse in women (pelvic pressure, bulging sensation) 4
• Neurologic symptoms suggesting spinal cord or peripheral nerve involvement 2

Physical examination should include 1, 2:

• Focused neurologic evaluation 1
• Pelvic examination in women to assess for cystocele or masses 2
• Digital rectal examination in men to assess prostate size and consistency 2

Management Approach

Immediate management requires prompt bladder decompression 1, 2:

• Urethral or suprapubic catheterization 1, 2
• Suprapubic catheters may be superior for short-term management, improving patient comfort and decreasing bacteriuria 1, 2

Subsequent management depends on identifying and treating the underlying cause 2, 5:

• Discontinue or reduce dose of causative medications 3
• Initiate alpha-blockers in men with BPH-related retention 1, 2
• Treat infectious or inflammatory conditions appropriately 2
• Refer to urology for structural abnormalities requiring surgical intervention 5

Important Caveats

Post-coital voiding is recommended to prevent urinary tract infections, not urinary retention 4. The temporal association between sexual activity and urinary retention likely reflects coincidental timing rather than direct causation in most cases. If urinary retention consistently occurs after intercourse, investigation for underlying obstructive, neurologic, or pharmacologic causes is warranted 1, 2, 5.