What is the best tumor lysis syndrome prevention approach for this patient?

A 59-year-old man is diagnosed with high grade lymphoma. Chemotherapy is prescribed. His oncologist orders rasburicase and intravenous fluid, normal saline, at 100 ml per hour. The patient is making urine, approximately 75 ml per hour.

Tumor Lysis Syndrome

Prevention

It is noted that the patient’s creatinine increases from normal to 1.3 mg/dL. His phosphorus level is 7.2 mg/dL, calcium 8.4 mg/dL, and his uric acid level is 7.5 mg/dL. The serum potassium is 5.6 mg/dL.

Please answer the following questions:

For tumor lysis syndrome prevention, what is the next step in management?
* Switch IV fluid to sodium bicarbonate
* Increase the rate of the IV fluid to 250 ml/hr
* Order lokelma (sodium zirconium cyclosilicate)
* Add allopurinol to the treatment regimen

Increase the rate of the IV fluid for tumor lysis syndrome prevention

What is the primary treatment for preventing tumor lysis syndrome?
A
Radiation therapy
B
Intravenous fluids
C
Chemotherapy
D
Surgery

B Intravenous Fulid

Which medication is used to lower uric acid levels in patients at high risk for tumor lysis syndrome?
A
Allopurinol
B
Ibuprofen
C
Rasburicase
D
Aspirin

D Rasburicase

What electrolyte imbalance is NOT typically associated with tumor lysis syndrome?
A
Hypocalcemia
B
Hyperkalemia
C
Hypernatremia
D
Hyperphosphatemia

C: Hypernatremia

What is the primary goal of aggressive volume expansion if the goal is tumor lysis syndrome prevention?
A
To increase serum potassium levels
B
To decrease blood pressure
C
To achieve a urine output of at least 80 to 100 mL/h
D
To promote weight gain

C To achieve a urine output of at least 80 to 100 ml per hour

Why is intravenous fluid with sodium bicarbonate not appropriate for patients with high serum phosphorus levels?
A
It decreases urine output
B
It increases the risk of calcium phosphorus precipitation
C
It can cause dehydration
D
It has no effect on uric acid clearance

B It increases the risk of calcium phosphorus precipitation.
Sodium bicarbonate is no longer preferred in tumor lysis syndrome prevention for this reason.

Discussion:

Tumor Lysis Syndrome Prevention

Overview of Tumor Lysis Syndrome (TLS)

Tumor lysis syndrome is a serious condition that occurs when malignant cells rapidly break down, leading to various metabolic abnormalities.

Key features include:
Hyperuricemia (elevated uric acid levels)
Hyperkalemia (elevated potassium levels)
Hyperphosphatemia (elevated phosphate levels)
Hypocalcemia (low calcium levels)

Clinical manifestations can include acute kidney injury because of the deposition of uric acid or calcium phosphate crystals in the renal tubules, as well as potential cardiac arrhythmias from the release of these substances.

Initial Management Strategies

The cornerstone of tumor lysis syndrome prevention and treatment is the administration of intravenous fluids to promote a faster urine flow rate. The most appropriate next step in management is to:
Increase the intravenous saline rate.

For patients at risk of TLS, especially those undergoing chemotherapy, aggressive volume expansion is crucial to achieve a urine output of at least 80 to 100 mL/h.

Treatment of Established TLS

Management of established TLS includes:
Intravenous volume expansion
Urate-lowering therapy
Management of hyperkalemia and hyperphosphatemia
Kidney replacement therapy in refractory cases

Rasburicase, a recombinant urate oxidase, is effective as it enhances the solubility of uric acid in urine and rapidly reduces serum urate levels. It is preferred for patients at high risk for TLS.

Specific Patient Considerations

For the patient with high-grade lymphoma, the risk of TLS is heightened immediately following chemotherapy. If the patient presents with high serum phosphorus and potassium levels, increasing the saline infusion rate is essential to:
Promote potassium excretion
Decrease precipitation of phosphorus and uric acid by increasing urine volume

For this patient, an intravenous fluid rate of 250 mL/h with normal saline is appropriate. In select cases, using a loop diuretic may also help maintain urine flow.

Considerations for Urine Alkalinization

While intravenous fluids with sodium bicarbonate can alkalinize urine and enhance uric acid clearance, they also pose a risk of calcium-phosphate precipitation, which can further damage the kidneys. Therefore, this approach is not suitable for patients with high serum phosphorus levels.

Management of Hyperkalemia

Sodium zirconium cyclosilicate (lokelma) can be used to treat hyperkalemia but does not improve urine flow. It is important to address hyperkalemia while ensuring adequate urine output.

Prophylaxis and Treatment Options

Rasburicase is generally preferred over allopurinol for TLS prophylaxis because of its mechanism of action. Rasburicase directly breaks down uric acid, while allopurinol does not have the same effect. If serum uric acid levels are adequately controlled with rasburicase, there is no benefit to switch to allopurniol.