What is the diagnosis and treatment for a patient with a physiologically distended urinary bladder, significant post-void residual urine, and a normal-sized prostate gland with concretion, given a pre-void volume of 221 ml and post-void volume of 199 ml on KUB (Kidneys, Ureters, Bladder) ultrasound?

Diagnosis and Treatment for Significant Post-Void Residual Urine

This patient has urinary retention with a clinically significant post-void residual (PVR) of 199 mL, indicating impaired bladder emptying that requires immediate intervention with clean intermittent catheterization and evaluation for the underlying cause.

Medical Diagnosis

Primary Diagnosis: Urinary Retention with Elevated Post-Void Residual

• The PVR of 199 mL approaches the clinically significant threshold of 200-300 mL that indicates bladder dysfunction 1, 2
• The bladder emptying efficiency is severely impaired at only 10% (voided only 22 mL out of 221 mL total volume) 3
• This PVR level places the patient at high risk for bacteriuria and urinary tract infections, as PVR >180 mL has an 87% positive predictive value for bacterial growth 4
• The prostate concretion (prostatic calculi) is noted but the prostate size is reported as normal, making benign prostatic hyperplasia less likely as the primary cause 5

Differential Considerations:

• Detrusor underactivity/bladder decompensation - most likely given the poor emptying efficiency and normal prostate size 6
• Neurogenic bladder dysfunction - must be ruled out with detailed neurologic history including stroke, diabetes with neuropathy, spinal cord pathology, or Parkinson's disease 1
• Bladder outlet obstruction - less likely given normal prostate size, but urethral stricture or bladder neck dysfunction should be considered 1

Immediate Management

Initiate Clean Intermittent Catheterization:

• Begin intermittent catheterization every 4-6 hours to prevent bladder volumes exceeding 500 mL 1
• This is the first-line intervention for PVR >100 mL and is preferred over indwelling catheters to reduce infection risk 1
• Catheterization should continue until the underlying cause is identified and treated 1

Diagnostic Workup Required

Confirm the PVR measurement:

• Repeat PVR measurement at least 2-3 times due to marked intra-individual variability before making definitive treatment decisions 1, 2
• Use ultrasound measurement rather than catheterization when possible to minimize infection risk 1

Neurologic evaluation:

• Obtain detailed neurologic history including stroke, multiple sclerosis, spinal cord injury, diabetes with neuropathy, or other conditions affecting bladder innervation 1
• Perform focused neurologic examination of lower extremities and perineal sensation 1
• If neurologic disease is present or suspected, proceed directly to urodynamic studies with EMG to diagnose detrusor-sphincter dyssynergia and determine bladder pressures 1

Additional testing:

• Uroflowmetry to assess maximum flow rate (Qmax <10 mL/sec suggests obstruction) 6, 2
• Pressure-flow studies if Qmax >10 mL/sec to differentiate obstruction from detrusor underactivity 6
• Urethrocystoscopy if there is history of hematuria, urethral stricture risk factors, or prior lower urinary tract surgery 6

Pharmacological Management

No immediate pharmacological therapy is indicated until the underlying cause is determined:

• Avoid antimuscarinic medications (for overactive bladder) as they are contraindicated with PVR >250-300 mL 1
• Alpha-blockers (alfuzosin, doxazosin, silodosin, tamsulosin, terazosin) may be considered if bladder outlet obstruction is confirmed, despite the normal prostate size 5, 7
• Bethanechol and other cholinergic agonists are NOT effective for detrusor underactivity and should not be used 6
• 5-alpha reductase inhibitors (finasteride, dutasteride) are not indicated given the normal prostate size 5

Monitoring and Follow-up

Short-term monitoring:

• Repeat PVR measurement 4-6 weeks after initiating any treatment to assess response 1
• Monitor for urinary tract infections with urine cultures if symptomatic 4
• Consider antibiotic prophylaxis if recurrent UTIs develop 6

Long-term management:

• Regular voiding charts to track bladder emptying patterns 6
• Periodic uroflowmetry and PVR measurements to monitor progression 6
• If neurogenic bladder is confirmed, perform videourodynamics with fluoroscopy to identify vesicoureteral reflux and anatomic abnormalities 1

Critical Pitfalls to Avoid

• Do not base treatment decisions on a single PVR measurement - always confirm with repeat testing due to high intra-individual variability 1, 2
• Do not assume elevated PVR alone indicates obstruction - it cannot differentiate between obstruction and detrusor underactivity without urodynamic studies 1
• Do not delay evaluation in patients with neurologic conditions - they require urgent assessment to prevent upper tract damage 1
• Avoid indwelling catheters when intermittent catheterization is feasible - indwelling catheters significantly increase UTI risk 1
• Do not start alpha-blockers empirically without confirming the diagnosis, as they will not help detrusor underactivity 6

Prognosis

• PVR volumes >200-300 mL predict a less favorable response to medical treatment and may herald disease progression 1, 2
• No specific PVR threshold alone mandates surgery - the decision must incorporate symptoms, quality of life, and risk of complications 1
• Treatment success depends on identifying and addressing the underlying cause (obstruction vs. detrusor dysfunction) 6, 1