Array

Tumor Lysis Syndrome

Click for pdf: Tumor lysis syndrome

Background

Tumor lysis syndrome (TLS) in pediatric patients is an oncologic emergency that involves complications of hematologic or solid malignancies. Tumor destruction may be due to spontaneous or treatment-related causes, resulting in electrolyte and metabolic imbalances. Classically, tumor lysis is associated with cytotoxic chemotherapy, including treatment with corticosteroids.

Electrolyte disturbances, such as hyperkalemia, hyperphosphatemia, and hypocalcemia can result in life threatening conditions, as can hyperuricemia. Examples include renal failure and dysrhythmias. It is therefore crucial to identify patients at risk of TLS quickly and to proceed with treatment options in an effort to minimize complications.

Causes of electrolyte imbalance and the resulting symptoms

Hyperkalemia

Causes: Cell lysis results in increased potassium levels in the extracellular space, which destabilizes polarized membranes (e.g.: muscle cells), and may trigger life-threatening arrhythmias.

Signs & Symptoms: Patients may develop muscle cramps, muscle weakness, paresthesias, nausea, vomiting and diarrhea. Severely increased levels may lead to ECG changes, such as widened QRS complexes and peaked T waves, and ultimately ventricular dysrhythmias.

Hyperphosphatemia

Causes: Atypical lymphoblasts contain significantly higher concentrations of phosphate than normal lymhoblasts. Upon lysis, excess phosphate is released into the circulation, and is ultimately eventually excreted by the kidneys. Hyperphosphatemia, may be exacerbated by underlying renal insufficiency, uric acid crystal nephropathy, and metabolic acidosis. Hyperphosphatemia-related renal failure results when phosphate and calcium precipitate in the nephron or collecting system.

Symptoms: Seizures, lethargy, vomiting and diarrhea

Hyperuricemia

Causes: High turnover within tumor cells produces intracellular purine nucleic acids. With cell lysis, the uric acid that is produced from purine catabolism is released, and accumulates in the renal collecting duct. The resulting nephropathy may be further exacerbated by pre-existing renal insufficiency (i.e. calcium-phosphate salt crystallization, nephrotoxic medications, etc…)

Symptoms: Oliguria, anuria and lethargy

Hypercalcemia

Causes: Low calcium levels may result from calcium phosphate precipitation, and therefore often occurs concurrently with hyperphosphatemia.

Symptom & Signs: Rarely muscles cramps, tetany, seizures, prolonged QT intervals and resulting dysrhythmias may result.

Management of tumor lysis syndrome

  Management Recommendation

Hyperkalemia

   Moderate/Asymptomatic (>6.0mmol/L) Avoid IV or oral K+

ECG monitoring

Sodium polystrene sulfonate (kayexalate)

Severe

(>7.0mmol/L)

Above, plus:

Membrane stabilization:

i) 1 amp Calcium gluconate or Calcium chloride

Potassium shift:

i)    Insulin bolus + sugar (D50W)

ii)  Sodium bicarbonate IV (never a line in which calcium was previously infused)

iii) β agonist inhaled (e.g.: salbutamol)

Potassium excretion:

i)   Furosemide (Lasix)

ii) Kayexalate

iii)   Hemodialysis for refractory hyperkalemia

Hyperphosphatemia

Moderate

(>2.1 mmol/L)

Avoid IV phosphate administration

Phosphate binder (oral/nasogastric aluminum hydroxide)

Severe Hemodialysis

Hyperuricemia

  Fluid hydration

Increased uric acid excretion

i) Allopurinol

ii) Hemodialysis

Increased uric acid breakdown

i) Rasburicase

Clinical dehydration

  Resuscitate with isotonic solution followed with D5 normal saline at increased maintenance rate (typically twice maintenance to maximizes GFR and excretion of uric acid, phosphate and potassium)

* Be careful not to cause volume overload in renal failure patients

References

  1. Coiffier B, Altman, A, Pui CH, et al. Guidelines for the new management of pediatric and adult tumor lysis syndrome: an evidence-based review. J Clin Oncol 2008; 26(16):2767-78.
  2. Zonfrillo MR. Management of pediatric tumor lysis syndrome in the emergency department. Emerg Med Clin N Am 27 (2009):497-504.

Acknowledgements

Writer: Michelle Lai

Resident editor- Katryn Paquette

Post Comment

You must be logged in to post a comment.

a place of mind, The University of British Columbia

Learn Pediatrics
Vancouver, BC, Canada

Emergency Procedures | Accessibility | Contact UBC  | © Copyright The University of British Columbia