What is the workup for a dislodged nephrostomy tube?

Workup for Dislodged Nephrostomy Tube

When a nephrostomy tube becomes dislodged, immediate imaging with ultrasound followed by CT scan should be performed to assess the status of the collecting system and guide replacement options. 1

Initial Assessment

• Timing of dislodgement:

  • Within 24 hours of initial placement: High risk of tract collapse
  • After 1-2 weeks: Tract is typically mature 1

• Clinical evaluation:

  • Vital signs (assess for sepsis/infection)
  • Flank pain (suggests urinary obstruction)
  • Urine output (decreased output suggests obstruction)
  • Hematuria (may indicate vascular injury)
  • Signs of infection (fever, chills, altered mental status)

Diagnostic Workup

1. Laboratory studies:

   • Complete blood count (assess for infection or bleeding)
   • Renal function tests (BUN, creatinine)
   • Urinalysis and urine culture (if infection suspected)

2. Imaging:

   • Ultrasound: First-line imaging to assess for hydronephrosis and confirm tube position 2
   • CT scan: Provides detailed information about:
     • Degree of hydronephrosis
     • Status of nephrostomy tract
     • Presence of urinoma or hematoma
     • Alternative access routes if needed 3

Management Algorithm

For mature tracts (>1-2 weeks old):

1. Attempt reinsertion through existing tract:

   • Use guidewire technique under ultrasound guidance
   • Consider ureteroscope-aided reinsertion for collapsed tracts 4
   • Success rates are high (90%) when performed within 24 hours of dislodgement 4

2. If reinsertion fails:

   • Create new nephrostomy tract under ultrasound and fluoroscopic guidance
   • Technical success approaches 100% for dilated systems and 80-90% for non-dilated systems 1

For immature tracts (<1-2 weeks old):

1. Create new nephrostomy tract:

   • Use ultrasound for initial access followed by fluoroscopy for tube placement 1
   • Consider retrograde ureteral stenting as an alternative if anatomically feasible 3

2. If patient has sepsis/infection:

   • Urgent decompression is required
   • PCN placement should be prioritized over retrograde stenting due to higher technical success rate (100% vs 80%) 1

Special Considerations

• Patients with pyonephrosis:

  • Higher risk of septic shock (up to 10%) 1
  • Require broad-spectrum antibiotics targeting uropathogens

• Patients with bleeding:

  • Persistent bleeding should prompt consideration of arteriographic evaluation for vascular injuries 3
  • Vascular injuries may require transcatheter embolization 3

• Prevention of future dislodgement:

  • Consider pigtail with balloon design for better retention 5
  • Ensure proper fixation and patient education on tube care

Follow-up

• Confirm proper tube position and function with nephrostogram 24-48 hours after replacement
• Regular assessment of continued need for nephrostomy tube
• Monitor for infection as rates increase with duration of catheter placement (14% overall with median time to infection of 44 days) 1

The workup and management of dislodged nephrostomy tubes requires prompt action to prevent complications such as obstruction, infection, and renal damage. The approach should be guided by the maturity of the tract, the patient's clinical status, and the availability of interventional expertise.