Treatment of Oliguria in Tumor Lysis Syndrome
Oliguria in tumor lysis syndrome requires aggressive hydration, rasburicase administration, and early initiation of renal replacement therapy when indicated by persistent electrolyte abnormalities or volume overload unresponsive to diuretics. 1, 2
Initial Management
Hydration and Urine Output Maintenance
- Start aggressive IV hydration through central venous access at 200-300 mL/hour
- Target urine output of at least 100 mL/hour in adults (3 mL/kg/hour in children <10 kg) 2
- When possible, begin hydration 48 hours before tumor-specific therapy 1
- Loop diuretics (or mannitol) may be required to maintain adequate urine output 1
- Important caveat: Avoid diuretics in patients with concomitant obstructive uropathy or hypovolemia 1
Rasburicase Administration
- Administer rasburicase to all patients with clinical TLS 1, 2
- Rasburicase rapidly degrades uric acid, with 96% of patients achieving uric acid levels ≤2 mg/dL within 4 hours of administration 3
- Dosing: 0.2 mg/kg/day as a 30-minute infusion 3
Management of Electrolyte Abnormalities
Hyperkalemia Management
- Mild (<6 mmol/L) asymptomatic hyperkalemia:
- Correct with hydration, loop diuretics, and sodium polystyrene 1 g/kg (oral or enema) 1
- Severe hyperkalemia:
Hyperphosphatemia Management
- Mild hyperphosphatemia (<1.62 mmol/L): No treatment needed or use aluminum hydroxide at 50-100 mg/kg/day divided in 4 doses 1, 2
Hypocalcemia Management
- Asymptomatic hypocalcemia: No treatment required 1, 2
- Symptomatic hypocalcemia (tetany, seizures): Administer calcium gluconate 50-100 mg/kg as a single dose, cautiously repeating if necessary 1, 2
Renal Replacement Therapy for Oliguria
Indications for Dialysis
Initiate renal replacement therapy when any of the following occur 1:
- Persistent hyperkalemia unresponsive to medical management
- Severe metabolic acidosis
- Volume overload unresponsive to diuretic therapy
- Overt uremic symptoms (pericarditis, severe encephalopathy)
- Severe progressive hyperphosphatemia (>6 mg/dL)
- Severe symptomatic hypocalcemia
Dialysis Modalities
Intermittent hemodialysis (IHD):
- Uric acid clearance approximately 70-100 mL/min
- Plasma uric acid level falls by about 50% with each 6-hour treatment 1
- Particularly effective for rapid correction of electrolyte abnormalities
Continuous renal replacement therapies (CRRT):
Peritoneal dialysis:
- Less efficient for solute removal compared to IHD and CRRT
- Generally not recommended for TLS management 1
Frequency of Dialysis
- Daily dialysis is recommended for patients with TLS and oliguria 1
- Frequent treatments improve the course of TLS with kidney damage
Monitoring
- Regular assessment of urine output, serum electrolytes, and renal function
- Calculate corrected calcium: Total calcium (mg/dL) + 0.8 × [4 - Serum albumin (g/dL)] 2
- Monitor for signs of volume overload or depletion
- Continuous ECG monitoring for patients with hyperkalemia 1, 2
Common Pitfalls to Avoid
- Using diuretics before correcting hypovolemia 2
- Delaying rasburicase administration in patients with rising uric acid levels 2
- Waiting too long to initiate renal replacement therapy in patients with persistent oliguria
- Treating asymptomatic hypocalcemia, which may worsen calcium phosphate deposition 1, 2
- Inadequate monitoring of electrolyte abnormalities during treatment
Oliguria in TLS represents a medical emergency that requires prompt intervention to prevent further kidney injury and potentially fatal complications. Early recognition and aggressive management significantly improve outcomes and reduce mortality.