What is the best course of action for a 56-year-old male with urinary urgency, inability to pass urine, and a negative urinalysis, who had 40 ml of urine obtained via catheterization (cath)?

This is NOT Urinary Retention

A post-void residual of only 40 mL is completely normal and rules out urinary retention as the cause of this patient's symptoms. 1, 2

Understanding the Clinical Picture

This 56-year-old male presents with urinary urgency and inability to pass urine, but the catheterization yielded only 40 mL—a finding that fundamentally changes the diagnostic approach:

• Normal bladder emptying is defined as PVR <100 mL, and values this low indicate the bladder was essentially empty when catheterized 2
• True acute urinary retention typically presents with volumes >300-500 mL and a palpably distended, painful bladder 1, 3
• The negative urinalysis makes urinary tract infection unlikely as a cause 4

What This Patient Actually Has

The combination of urgency with inability to void despite an empty bladder suggests:

• Overactive bladder with detrusor overactivity—the patient feels urgency but has little to no urine in the bladder 4, 5
• Bladder hypersensitivity or irritability causing a false sensation of fullness 4
• Possible urethral stricture or obstruction preventing the small amount of urine from passing, though 40 mL makes this less likely 1

Immediate Management

Do NOT place an indwelling catheter—this patient does not have retention and catheterization will only increase infection risk without benefit. 4, 6

Diagnostic Workup Needed:

• Repeat PVR measurement after the patient attempts to void naturally (not via catheter) to confirm this finding, as there is marked intra-individual variability 2
• Bladder diary for 3 days documenting voiding frequency, urgency episodes, and voided volumes 4
• Uroflowmetry if available to assess flow pattern and rule out obstruction 4, 2
• Consider urodynamic studies if symptoms persist despite initial management, particularly to evaluate for detrusor overactivity 4

Initial Treatment Approach:

Behavioral interventions should be first-line: 5

• Timed voiding every 2-3 hours to prevent urgency episodes 4
• Fluid management—avoid excessive intake but maintain adequate hydration (2-3 L/day unless contraindicated) 4
• Bladder training to gradually increase intervals between voids 4

Pharmacologic therapy for overactive bladder: 4, 5

• Anticholinergic medications (e.g., trospium, oxybutynin) reduce urgency and frequency by 2-4 voids per day 5
• β3-agonists (e.g., mirabegron) are an alternative with fewer anticholinergic side effects 5
• Alpha-blockers are NOT indicated in this case—they are used for bladder outlet obstruction from BPH, which this patient does not have based on the low PVR 1, 7

Critical Pitfalls to Avoid

• Do not treat this as urinary retention—the 40 mL PVR excludes this diagnosis 1, 2
• Do not place an indwelling catheter—this increases infection risk without addressing the underlying problem and is contraindicated for overactive bladder management 4, 6
• Do not start alpha-blockers empirically—these are for obstruction, not overactive bladder, and the low PVR indicates no significant obstruction 1, 7
• Do not assume prostate pathology—while BPH is common in this age group, the clinical picture and low PVR suggest a bladder storage problem, not an outlet obstruction 4, 5

Follow-Up Strategy

• Reassess in 4-6 weeks after initiating behavioral and pharmacologic therapy 4
• Repeat PVR measurement if symptoms persist or worsen to monitor for development of retention 2
• Consider urology referral if symptoms are refractory to first-line treatments or if urodynamic studies are needed 4