Gold Standard Diagnostic Testing for Urinary Retention with Distended Abdomen and No Urine in Foley Catheter
Retrograde cystography (plain film or CT) is the gold standard diagnostic test for evaluating urinary retention with a distended abdomen when no urine is obtained from a Foley catheter, as it can accurately identify bladder rupture, obstruction, or catheter malposition. 1
Initial Assessment
- A distended abdomen with no urine return from a Foley catheter suggests either catheter malposition, obstruction, or bladder rupture 1
- Clinical indicators of potential bladder rupture include inability to void, low urine output, increased BUN and creatinine, abdominal distention, suprapubic pain, and low-density free intraperitoneal fluid on abdominal imaging 1
- Urinary retention with a non-draining catheter may indicate the catheter is not properly positioned in the bladder or the balloon has slipped into the urethra 2
Diagnostic Approach
First-Line Imaging: Retrograde Cystography
- Retrograde cystography (either plain film or CT) is the technique of choice to diagnose bladder injury and evaluate catheter position 1
- Both plain film and CT cystography have similar specificity and sensitivity for diagnosing bladder rupture 1
- The technique involves:
- Retrograde, gravity filling of the bladder with contrast
- Minimum volume of 300 mL or until patient reaches tolerance
- For plain film: minimum of two views (maximal fill and post-drainage)
- For CT: dilute water-soluble contrast to prevent artifacts 1
CT Cystography Considerations
- CT cystography can identify intraperitoneal or extraperitoneal bladder rupture with 100% sensitivity and 99% specificity when properly performed 1
- Simply clamping a Foley catheter to allow excreted IV contrast to accumulate is not appropriate as it will not provide adequate bladder distention and may miss injuries 1
- CT cystography can also identify catheter malposition, showing whether the catheter tip and balloon are properly positioned in the bladder 2
Ultrasound Evaluation
- Ultrasound of the kidneys and retroperitoneum can detect hydronephrosis associated with acute urinary tract obstruction (sensitivity >90%) 1
- Ultrasound can also evaluate bladder distension and help localize the level of obstruction 1
- If the Foley balloon is not visualized within the bladder on ultrasound, the urethra should be scanned to locate the balloon 2
- Transrectal ultrasonography may be useful in diagnosing retained or malpositioned Foley catheters in male patients 3
Common Pitfalls and Caveats
- Failure to adequately distend the bladder during cystography can lead to false-negative results 1
- Urinary retention with a distended abdomen but no urine in the Foley may be due to:
- In patients with spinal cord injury, decreased muscle mass leads to lower baseline creatinine levels; an increase >1.5 times the baseline may indicate acute kidney injury even if still within normal laboratory range 2
Management Considerations
- Initial management involves ensuring proper catheter placement and complete bladder decompression 4
- If catheter malposition is confirmed, proper repositioning or replacement is necessary 2
- For intraperitoneal bladder rupture, surgical repair is required 1
- For uncomplicated extraperitoneal bladder injuries, catheter drainage for 2-3 weeks is standard treatment 1
- Complicated extraperitoneal bladder ruptures should be surgically repaired 1
By following this diagnostic algorithm, clinicians can accurately identify the cause of urinary retention with a distended abdomen when no urine is obtained from a Foley catheter, allowing for appropriate management and preventing further complications.