Green Neon Urine from Nephrostomy Tube
Green neon-colored urine from a nephrostomy tube is almost always caused by intravenous administration of indigo carmine dye or propofol, and requires no specific management beyond confirming the medication history and reassuring the patient.
Etiology and Mechanism
The most common cause of bright green or neon-colored urine through a nephrostomy tube is indigo carmine (sodium indigotindisulfonate), which is used diagnostically during urological procedures 1. This dye is specifically employed to detect urinary leaks intraoperatively and can be administered:
- Intravenously at a dose of 40 mg by slow infusion, with a second 40 mg dose possible 20-30 minutes later if needed 1
- Directly through the nephrostomy tube if one was placed preoperatively 1
The dye is renally excreted and produces characteristic bright green/blue-green discoloration of urine that is visible through drainage systems 1.
Propofol is another medication that can cause green-tinged urine, though this is less commonly the primary cause of neon green coloration.
Clinical Assessment
Immediate Evaluation
- Review medication history to confirm recent indigo carmine administration or propofol use 1
- Assess for contraindications that should have precluded dye use: hemodynamic instability or creatinine clearance <10 mL/min 1
- Monitor vital signs to exclude sepsis, as fever or shock in a patient with a nephrostomy tube requires immediate attention 2, 3
Rule Out Infection
While green urine itself is benign when dye-related, patients with nephrostomy tubes have significant infection risk:
- 19% develop pyelonephritis within 90 days of nephrostomy placement 4
- 28.33% develop post-procedure fever in some series 5
- Check for fever, flank pain, or signs of sepsis that would indicate nephrostomy-related infection requiring urgent management 2, 3
Management Approach
If Dye-Related (Most Common)
- Reassure the patient that green discoloration from indigo carmine is expected and harmless 1
- No specific treatment required - the color will resolve as the dye is cleared renally over 24-48 hours
- Document the dye administration in the medical record
If No Dye History
- Consider other medications including propofol or other agents that can discolor urine
- Evaluate nephrostomy tube function to ensure proper drainage and no obstruction 1
- Assess for infection with urine culture from the nephrostomy tube, as infected urine can occasionally appear discolored 2, 6
Important Caveats
Rare Adverse Reactions to Indigo Carmine
While generally safe, indigo carmine has been associated with rare complications 1:
- Severe hypotension
- Hypoxia
- Subcutaneous erythema
- Cardiac arrest (extremely rare)
Monitor patients closely if dye was recently administered and they develop any systemic symptoms.
Nephrostomy Tube Infection Risk
The green color itself is benign, but do not miss concurrent infection 2, 4:
- Collect urine for culture before starting antibiotics if infection is suspected 3
- Start broad-spectrum antibiotics immediately if sepsis is present, then adjust based on culture results 2
- Consider tube exchange if the nephrostomy has been in place ≥2 weeks at time of infection, as this improves treatment response 2
- Ensure adequate drainage as this is lifesaving and mandatory in obstructed infected systems 2
Tube Patency
Green urine should flow freely through the nephrostomy tube. If output decreases or stops:
- Assess for tube obstruction which can occur from mucus, debris, or malposition 1
- Flush the tube gently if ordered and not contraindicated
- Contact interventional radiology or urology for tube evaluation or exchange if obstruction is suspected 1
Follow-Up
- No specific follow-up needed for dye-related green urine once the color resolves
- Routine nephrostomy care should continue per institutional protocols
- Culture results should be followed if obtained, though routine cultures at nephrostomy exchanges show no clear benefit 6