Occurs when chemotherapy rapidly lyses large numbers of tumor cells, releasing potassium, phosphate, and nucleic acids (uric acid).
Before you read
Test yourself first: 3 questions
Question 1 of 3
A client undergoing hemodialysis develops a headache, nausea, restlessness, and confusion near the end of the treatment. The nurse recognizes these as signs of which complication?
Answer: A. Disequilibrium syndrome results from rapid removal of urea during dialysis, creating an osmotic gradient that shifts water into the brain and causes cerebral edema. Symptoms include headache, nausea, restlessness, confusion, and in severe cases seizures. It is more common in new or aggressively dialyzed clients.
Question 2 of 3
A client undergoing chemotherapy for tumor lysis syndrome has a serum potassium of 6.8 mEq/L and peaked T waves on the ECG. Which prescribed intervention should the nurse anticipate administering first?
Answer: A. Hyperkalemia with ECG changes is life-threatening. IV calcium gluconate is given first to stabilize the cardiac membrane and protect against fatal arrhythmias. Insulin with dextrose and other measures shift or remove potassium afterward but do not provide immediate cardiac protection.
Question 3 of 3
The nurse is assessing the neurovascular status distal to a fractured femur with a cast in place. Which finding is the EARLIEST indicator of impaired arterial perfusion?
Answer: B. Pain, particularly pain out of proportion and pain with passive stretch, is the earliest sign of neurovascular compromise. Pulselessness, pallor, paresthesia, and paralysis are late findings; waiting for an absent pulse risks permanent damage.
Keep the streak going with more questions like these, each with a full rationale.
What is tumor lysis syndrome?
This produces hyperkalemia, hyperphosphatemia, hyperuricemia, and a resulting hypocalcemia. The high uric acid and phosphate can crystallize in the kidneys, causing acute kidney injury, and hyperkalemia can cause fatal arrhythmias. Memory aid: high potassium, high phosphate, high uric acid, low calcium.
Key points to remember
- Occurs when chemotherapy rapidly lyses large numbers of tumor cells, releasing potassium, phosphate, and nucleic acids (uric acid).
- Electrolyte pattern: hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia.
- Hyperkalemia is the most immediately life-threatening abnormality due to cardiac arrhythmia risk.
- Uric acid and calcium-phosphate crystals can precipitate in renal tubules, causing acute kidney injury.
- Aggressive IV hydration and allopurinol or rasburicase are used to prevent and treat hyperuricemia.
- Highest risk is with bulky, rapidly proliferating cancers like acute leukemia and high-grade lymphoma shortly after treatment begins.
Nursing priorities
- Administer aggressive IV fluids to maintain high urine output and flush uric acid and phosphate.
- Give allopurinol or rasburicase as prescribed to lower uric acid.
- Monitor potassium and cardiac rhythm closely; treat hyperkalemia promptly.
- Monitor electrolytes, calcium, phosphate, uric acid, and renal function (BUN, creatinine, urine output).
- Initiate prevention in high-risk clients before and during chemotherapy with hydration and prophylactic medications.
Labs & values
Patient teaching
- Report decreased urination, muscle cramps, numbness/tingling, palpitations, or seizures during or after chemotherapy.
- Drink fluids as encouraged to support kidney function and flushing.
- Understand the importance of lab monitoring and prophylactic medications around chemotherapy.
- Know that this risk is highest in the first days after starting treatment for certain cancers.
Red flags: report now
- Cardiac dysrhythmias from hyperkalemia (peaked T waves, widening QRS) are life-threatening and require emergent treatment.
- Decreasing urine output, rising creatinine, or signs of acute kidney injury must be reported immediately.
- Symptomatic hypocalcemia (tetany, seizures, positive Chvostek/Trousseau) requires urgent intervention.
References
Clinical references for this topic
