What to order for suspected Tumor Lysis Syndrome (TLS)?

From the Guidelines

If suspected Tumor Lysis Syndrome (TLS), order the following tests:

1. Complete blood count (CBC)
2. Comprehensive metabolic panel (CMP)
3. Uric acid level
4. Lactate dehydrogenase (LDH)
5. Phosphorus level
6. Calcium level
7. Electrocardiogram (ECG) These tests help assess for key markers of TLS, including electrolyte imbalances, elevated uric acid, and potential organ dysfunction, as recommended by guidelines for the management of pediatric and adult tumor lysis syndrome: an evidence-based review 1. The CBC can indicate tumor lysis through changes in blood cell counts. The CMP evaluates kidney function and electrolyte levels. Uric acid, LDH, phosphorus, and calcium are specific markers that can be elevated in TLS. An ECG can detect cardiac arrhythmias that may occur due to electrolyte disturbances.

Additionally, consider ordering: 8. Urinalysis 9. Coagulation studies (PT/INR, aPTT) These provide further information on kidney function and potential coagulation abnormalities, as suggested by the consensus conference on the management of tumor lysis syndrome 1.

For high-risk patients, rasburicase should be administered along with hydration 1, as it affects a rapid and complete degradation of uric acid to allantoin, potentially allowing a prompt continuation of chemotherapy. Allopurinol can also be used for intermediate-risk patients or those with low-risk of TLS, but it only prevents the formation of uric acid and does not reduce uric acid produced before the initiation of treatment 1.

Prompt recognition and monitoring of TLS is crucial, as it can rapidly lead to acute kidney injury, cardiac arrhythmias, and other life-threatening complications. Early detection allows for timely intervention, including aggressive hydration, electrolyte management, and potentially the use of medications like allopurinol or rasburicase to manage uric acid levels, as emphasized in guidelines for the management of pediatric and adult tumor lysis syndrome: an evidence-based review 1.

From the FDA Drug Label

Tumor Lysis Syndrome (TLS) Clinical TLS was defined by changes in at least two or more laboratory parameters for hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia and at least one of the following events occurring within 7 days of treatment: renal failure/injury, need for renal dialysis, and/or serum creatinine increase >1.5 ULN, arrhythmia or seizure.

A total of 275 adult patients received at least one dose of study drug The median age was 56 years, 62% were males, 80% were Caucasian, 66% had leukemia, 29% had lymphoma; 18% were hyperuricemic (uric acid >7. 5 mg/dL) at study entry.

Patients in Arm A received Elitek for 5 days (n=92). Patients in Arm B received Elitek from day 1 through day 3 followed by oral allopurinol from day 3 through day 5 (overlap on day 3: Elitek and allopurinol administered approximately 12 hours apart) (n=92).

For suspected Tumor Lysis Syndrome (TLS), the following should be ordered:

• Rasburicase (Elitek): 0.2 mg/kg/day as a 30-minute infusion once daily for 5 days
• Allopurinol: 300 mg orally once a day for 5 days (may be started after 3 days of rasburicase)
• Laboratory monitoring: for hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia, and renal function 2
• Close monitoring for signs of clinical TLS, such as renal failure, arrhythmia, or seizure 2

From the Research

Laboratory Tests and Medications for Suspected Tumor Lysis Syndrome (TLS)

To manage suspected TLS, the following laboratory tests and medications are recommended:

• Uric acid levels: Monitor uric acid levels closely, as hyperuricemia is a key feature of TLS 3, 4, 5
• Electrolyte monitoring: Monitor electrolyte levels, including potassium, phosphorus, and calcium, as TLS can cause electrolyte imbalances 4, 5
• Rasburicase: Administer rasburicase, a recombinant urate oxidase, to reduce uric acid levels and prevent acute renal failure 3, 5, 6, 7
• Hydration and diuresis: Ensure intensive hydration and stimulate diuresis to help prevent renal failure 4, 5
• Allopurinol: Consider using allopurinol, a xanthine oxidase inhibitor, to reduce uric acid production 5, 6

Dosing and Administration of Rasburicase

The dosing and administration of rasburicase for suspected TLS are as follows:

• Fixed-dose rasburicase: A fixed dose of 6 mg can be effective in reducing uric acid levels in adults with TLS 3
• Weight-based dosing: Rasburicase can also be administered at a dose of 0.1-0.2 mg/kg, as used in some studies 7
• Single-dose or multiple-dose regimens: Both single-dose and multiple-dose regimens of rasburicase have been used in clinical practice, with the choice of regimen depending on the individual patient's needs and risk factors 3, 7

Patient Monitoring and Follow-up

Close monitoring of patients with suspected TLS is essential to prevent and manage complications:

• Regular laboratory tests: Monitor uric acid, electrolyte, and renal function tests regularly to assess the effectiveness of treatment and detect any potential complications 3, 4, 5
• Clinical assessment: Regularly assess patients for signs and symptoms of TLS, such as renal failure, seizures, or cardiac arrhythmias 4, 5