Tumor Lysis Syndrome – Understanding the Basics

• Tumor lysis syndrome requires healthcare providers to have an elevated level of clinical suspicion to recognize and improve patients’ outcomes. 
• Follow along this case study about tumor lysis syndrome, and learn some nursing considerations for screening TLS.
• Tumor lysis syndrome (TLS) is an oncological emergency resulting from the combination a hematologic neoplasm and cytotoxic treatment. 

Medical emergencies can come from many different physiological sources. A healthcare provider’s ability to recognize a time-sensitive medical emergency at the first sign of symptoms and use algorithmic management of airway (A), breathing (B), circulation (C) and definitive treatment, differential diagnosis, drugs, defibrillation (D) is paramount to maintaining blood circulation to a patient’s brain and heart.  

Common emergencies being common, conditions such as heart attack, stroke, seizures, and severe allergic reactions are most often recognizable.  

Less common infectious conditions such as Fournier’s gangrene, bacterial meningitis and Monkeypox need an emergency room nurse’s added vigilance. Beyond the ordinary, a cursory understanding and recognition of the uncommon can save a life in certain medical conditions.  

Spontaneous tumor lysis syndrome (STLS) is a complex, but rare severe electrolyte disturbance often occurring when hematological cancer patients have begun systemic chemotherapy.  

Tumor lysis syndrome (TLS) is an oncological emergency resulting from the combination a hematologic neoplasm and cytotoxic treatment.  

At the metabolic level, tumor lysis is the rapid breakdown of the malignant cell membrane, which releases the intracellular cell contents (uric acid, potassium, and phosphate) into the bloodstream.  

Case Study on Tumor Lysis Syndrome

A 46-year-old female with a recent diagnosis of aggressive B cell lymphoma arrives at your emergency department with a three-day history of nausea, vomiting, diarrhea, decreased appetite, fatigue, and lightheadedness.  

One week before admission, she received chemotherapy. She had lost 11kg during this period. There was no report of fevers. Her lab values showed elevated creatinine, uric acid, and phosphorus. Along with hypocalcemia. Physicians documented renal failure in this patient. By criteria, this patient is experiencing tumor lysis syndrome. 

Fundamentals of Tumor Lysis Syndrome

To understand TLS, we need an overview of the metabolic underpinnings.  

This patient had a significant cancer burden in the lymph nodes for which she received chemotherapy that caused a breakdown of the malignant cells and released cellular contents into the bloodstream.  

With the large release of intracellular components into her systemic circulation multiple electrolyte abnormalities resulted including an elevated potassium, phosphorus and nucleic acids that metabolize into uric acid along with a decrease in calcium. The combination having the potential to cause the following clinical abnormalities: acute kidney injury (AKI), heart arrhythmias, muscles cramps, weakness, and seizures.  

The electrolyte potassium requires the most surveillance, as hyperkalemia is a dangerous abnormality secondary to the risk of life-threatening cardiac arrhythmia. An increase of serum potassium >7 mmol/L can present a medical emergency that requires immediate treatment.  

Of note, tumor lysis syndrome can occur without chemotherapy in tumors with a high proliferative rate and large tumor burden regardless of sensitivity/exposure to cytotoxic (chemo) therapy. Patients receiving glucocorticoid therapy, which can cause the rapid lysis of tumor cells, are also at-risk for tumor lysis syndrome. 

Laboratory Diagnosis of Tumor Lysis Syndrome

A laboratory diagnosis of tumor lysis syndrome comprises two or more abnormal lab values; hyperuricemia, hyperkalemia, hyperphosphatemia, and secondary hypocalcemia within three days before or up to seven days after cytotoxic therapy for malignancy.  

Along with the patient’s new-onset renal failure, she met the laboratory criteria for TLS according to the Cairo-Bishop definition.  

Risk Factors for TLS 

• Hematologic malignancy 
• Cytotoxic chemotherapy  
• Underlying renal disease 
• Underlying cardiac arrhythmias 
• Evidence of TLS (Before cytotoxic therapies) 
• Elevated LDH  
• Dehydration before treatment  
• Extensive disease 

Emergency Management of TLS 

• Monitoring labs (K+, PO4, Ca, uric acid, LDH, Cr) before and after cytotoxic therapy 
• Monitor fluid balance (Intake/Output) 
• Renal consultation and telemetry monitoring for susceptible patients 
• Intravenous fluids (two or three liters per 24-hour period) 
• Medications to prevent hyperuricemia (Allopurinol or Rasburicase)

Can We Prevent TLS?

Prevention of TLS relies on early identification and treatment using a regimen of hydration (intravenous crystalloid administration, hyperuricemia prevention, and, in rare cases, hemodialysis concurrent with chemotherapy).  

In patients with existing heart failure, hydration requires monitoring. Standard treatment metrics include monitoring of daily fluids, weight checks and laboratory data for uric acid, potassium, calcium, and phosphate. These patients should avoid nephrotoxic medications.  

The initial goal in TLS management is to increase urinary output, diluting the effects of the dissolved uric acid. If tumor cell death is present, hydration should continue.  

The Bottom Line

Tumor lysis syndrome requires healthcare providers to have an elevated level of clinical suspicion to recognize and improve patients’ outcomes.  

Though life-threatening, most cases of tumor lysis syndrome do not result in renal or metabolic emergencies.  

Optimal patient care includes ICU transfer, renal consultation, potential hemodialysis, withholding subsequent chemotherapy and/or transfer to a tertiary care center. 

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