Tumor Lysis Syndrome in Children: Prevention MCQ

Clinical Scenario:

An 8-year-old boy with acute lymphoblastic leukemia (ALL) started chemotherapy 2 days ago. His mother reports that he has not passed urine for the last 12 hours. On examination, he is lethargic and has puffiness around the eyes. Laboratory investigations reveal:

Investigation	Result
Serum sodium	132 mmol/L
Serum potassium	5.8 mmol/L
Bicarbonate	17 mmol/L
Creatinine	1.0 mg/dL
Phosphorus	2.8 mmol/L
Calcium	6.7 mg/dL (1.7 mmol/L)
Uric acid	12.3 mg/dL (732 μmol/L)
Lactate dehydrogenase (LDH)	4233 IU/L

How can this complication be prevented?

A. Fluid restriction
B. Delaying chemotherapy
C. Intravenous hyperhydration
D. Fresh frozen plasma infusion
E. Phosphate binders

Correct answer & Explanation:

Correct Answer: C. Intravenous hyperhydration

Explanation

This child is at risk of tumor lysis syndrome (TLS), a potentially life-threatening oncologic emergency that can occur after initiation of chemotherapy for rapidly proliferating, highly chemosensitive malignancies such as acute lymphoblastic leukemia. Rapid tumor-cell destruction releases intracellular contents, leading to hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia, and acute kidney injury.

The cornerstone of TLS prevention is vigorous intravenous hydration, started before chemotherapy and continued during treatment. Adequate hydration increases renal blood flow and urine output, promoting the urinary excretion of uric acid and phosphate and reducing the risk of renal injury.

Risk-adapted uric acid–lowering therapy is also important. Allopurinol is commonly used for lower-risk patients, whereas rasburicase is preferred for patients at high risk of TLS or with significant hyperuricemia.

Why not the other options?

A. Fluid restriction: Incorrect because adequate hydration is an important component of TLS prevention. Fluid restriction may increase the risk of renal complications.
B. Delaying chemotherapy: Incorrect. Chemotherapy should not routinely be delayed; appropriate TLS prophylaxis should be instituted before treatment.
D. Fresh frozen plasma infusion: Has no role in preventing TLS.
E. Phosphate binders: May have a role in managing hyperphosphatemia after TLS develops but do not constitute primary TLS prophylaxis.

Clinical Pearl

In a child with leukemia receiving chemotherapy, hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia, rising creatinine, oliguria, and elevated LDH should raise concern for TLS. Prevention relies on vigorous hydration plus risk-adapted uric acid–lowering therapy with allopurinol or rasburicase.

Reference

Tosi P, Barosi G, Lazzaro C, et al. Consensus conference on the management of tumor lysis syndrome. Haematologica. 2008;93(12):1877-1885.

You can also practice another MCQ on Cervical Lymphadenopathy.