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Tumor Lysis Syndrome

Introduction:
Tumor lysis syndrome is a lifethreatening metabolic emergency caused by the rapid destruction of cancer cells.
It can occur spontaneously or as a result of chemotherapy, radiation therapy, or surgery.
Tumor lysis syndrome is characterized by a constellation of metabolic abnormalities, including hyperkalemia, hyperphosphatemia, hypocalcemia, hyperuricemia, azotemia, and oliguria.

Causes:
Common cancers that can cause Tumor lysis syndrome: Leukemia, Lymphoma, Burkitt's lymphoma, Acute myeloid leukemia, Small cell lung cancer, Breast cancer, Ovarian cancer, and Testicular cancer.
Risk factors associated with Tumor lysis syndrome: High tumor burden, Rapidly growing tumors, Tumors sensitive to chemotherapy or radiation therapy, Preexisting renal dysfunction.

Pathophysiology:
The release of cellular contents from lysed cancer cells triggers a cascade of events.
Hyperkalemia: can cause cardiac arrhythmias and sudden death.
Hyperphosphatemia: can cause acute kidney injury, renal failure, and hypocalcemia.
Hypocalcemia: can cause neuromuscular irritability and seizures.
Hyperuricemia: can cause uric acid crystallization in the kidneys and renal failure.
Azotemia and oliguria: can occur as a result of renal failure.

Clinical Manifestations:
Nausea, vomiting, diarrhea, and abdominal pain.
Muscle weakness, seizures, coma, and cardiac arrhythmias.
Renal failure.

Diagnosis:
Based on clinical symptoms and laboratory findings.
Laboratory tests: Serum potassium, phosphate, calcium, uric acid, blood urea nitrogen, and serum creatinine.
CairoBishop criteria: At least two metabolic disturbances within 3 days before or 7 days after initiation of therapy.

Treatment:
Intravenous fluids to correct dehydration and electrolyte imbalances.
Allopurinol or rasburicase to lower serum uric acid level.
Sodium bicarbonate to alkalinize the urine and prevent uric acid crystallization.
Dialysis to remove waste products from the blood.
Generally not recommended to supply calcium, as it can increase the calcium phosphate product and lead to further renal deposition and damage.

Prevention:
Identify patients at risk and start treatment before the condition develops.
Prophylactic treatment with allopurinol or rasburicase before chemotherapy or radiation therapy.
Avoid substances that can cause vasoconstriction of the renal vasculature, such as NSAIDs and iodinated contrast.

Conclusion:
Tumor lysis syndrome is a common oncologic emergency with potentially lifethreatening complications.
Early identification and prompt treatment are crucial to prevent severe complications and improve patient outcomes.