What imaging study is recommended for a patient with a leaking nephrostomy (percutaneous nephrostomy tube) tube?

Imaging for a Leaking Nephrostomy Tube

For a patient presenting with a leaking nephrostomy tube, perform a fluoroscopic nephrostogram (tubogram) as the initial imaging study to identify the site and cause of the leak, followed by CT with IV contrast if complications such as urinoma, abscess, or vascular injury are suspected.

Initial Imaging Approach

Fluoroscopic Nephrostogram (Tubogram)

• Inject water-soluble contrast material directly through the nephrostomy tube under fluoroscopic guidance to identify the exact location and mechanism of leakage 1
• This technique allows real-time visualization of contrast extravasation around the tube, tube malposition, tube dislodgement, or collecting system injury 1
• Fluoroscopy provides immediate assessment of tube patency, position within the collecting system, and integrity of the drainage pathway 1

When to Escalate to CT Imaging

• Obtain CT abdomen/pelvis with IV contrast if the nephrostogram shows significant extravasation, if clinical signs suggest complications (fever, sepsis, hypotension, expanding flank mass), or if the tube appears completely dislodged 2, 3
• CT with IV contrast is superior for detecting perirenal fluid collections, urinomas, abscesses, hematomas, and vascular injuries that may complicate a leaking nephrostomy 2, 3
• CT can identify adjacent organ injury (colon, spleen, pleura) that may have occurred during initial placement or subsequent manipulation 1, 4

Ultrasound Considerations

• Bedside ultrasound can be used as an adjunct to rapidly assess for hydronephrosis, perirenal fluid collections, or hematoma formation, but cannot definitively evaluate tube position or the drainage pathway 1, 3
• Ultrasound is particularly useful in the emergency department for initial triage but should not replace definitive imaging with fluoroscopy or CT 3
• Doppler ultrasound may help identify vascular complications if persistent hematuria accompanies the leak 1, 3

Clinical Context Matters

Signs Requiring Urgent Advanced Imaging

• Fever, sepsis, or signs of infection mandate immediate imaging (preferably CT with IV contrast) as sepsis is the most serious complication of nephrostomy tube problems and can be fatal 1, 5
• Persistent or recurrent gross hematuria after the initial post-placement period suggests vascular injury (pseudoaneurysm, arteriovenous fistula) requiring CT angiography or conventional angiography 1, 3
• Hypotension, tachycardia, or dropping hematocrit with a leaking tube indicates possible hemorrhage requiring urgent CT with IV contrast 1, 3
• Expanding flank mass or severe flank pain suggests urinoma or hematoma formation requiring CT evaluation 2, 3

Minor Leaks in Stable Patients

• For well-appearing patients with minor pericatheter leakage and no signs of infection or obstruction, fluoroscopic nephrostogram alone may suffice to guide management 1, 3
• Small amounts of leakage around the tube insertion site are common and may resolve with tube repositioning or upsizing 3, 4

Common Pitfalls to Avoid

Do Not Delay Imaging in High-Risk Scenarios

• Never delay definitive imaging in patients with suspected infection, as failed drainage with ongoing obstruction dramatically increases sepsis risk and mortality 5
• Sepsis contributed to death in patients where there was delay in diagnosis or therapy after nephrostomy complications 5
• The risk of serious complications is highest when instrumentation fails and renal drainage is not promptly re-established 5

Do Not Rely Solely on Clinical Assessment

• Asymptomatic bacteriuria is common with nephrostomy tubes and should not be treated, but infectious symptoms require aggressive imaging and management 3
• Gross hematuria is common immediately after placement (approximately 50% of patients), but hematuria returning after initial resolution or persisting beyond the immediate post-procedure period warrants investigation for vascular injury 1

Technical Considerations

• Always use water-soluble (not barium) contrast for nephrostogram to avoid peritoneal contamination if significant extravasation exists 1
• If the tube is completely dislodged and cannot be accessed for contrast injection, proceed directly to CT with IV contrast and delayed excretory phase imaging to assess the collecting system 1

Management Algorithm Based on Imaging Findings

If Nephrostogram Shows Minor Pericatheter Leak

• Tube repositioning or upsizing may resolve the issue without further imaging 3, 4
• Ensure the tube side holes are within the collecting system 4

If Nephrostogram Shows Complete Dislodgement

• Urgent tube replacement is required, preferably under ultrasound and fluoroscopic guidance 1
• CT guidance may be necessary for non-dilated systems, obese patients, or complex anatomy 2, 6

If CT Shows Urinoma or Abscess

• Percutaneous drainage of collections may be required in addition to nephrostomy tube management 2, 3
• Ensure adequate urinary drainage is established before removing any transcolonic or malpositioned catheters 4

If Imaging Shows Vascular Injury

• Angiography with selective embolization is the treatment of choice for pseudoaneurysms, arteriovenous fistulas, or active extravasation 1
• Most renal vascular injuries can be managed with minimally invasive embolization, preserving renal function 4