TUMOR LYSIS SYNDROME

Definition: hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia resulting from destruction of a large number of rapidly proliferating neoplastic cells.

1. Most often associated with Burkitts, ALL, but also other leukemias, breast ca, germ cell tumors, neuroendocrine tumors, small cell lung ca.

2. Most often occurs at the initiation of chemo, but may also be associated with radiotherapy, surgery, steroids.

Risk factors:

1. disease bulk

2. marked sensitivity to treatment

3. renal impairment

4. high serum LDH

5. high serum urate.

Metabolic abnormalities:

1. Hyperuricemia- results from increased purine degradation as cells die. Can lead to renal failure, mechanism not well understood.

2. Hyperkalemia- results from release from lysed cells. Can cause arrhythmia and sudden death.

3. Hyperphosphatemia- results from increased nucleoprotein breakdown. Causes hypocalcemia as below.

4. Hypocalcemia- hyperphosphatemia leads to precipitation, directly depresses PTH activity in bone, and decreases production of 1,25 VitD (if precipitation leads to ARF).

Prophylaxis:

1. allopurinol

2. IVF

3. monitor U/O

4. bicarbonate- keep urine pH>7

Treatment:

1. Hyperuricemia: allopurinol and bicarbonate, as above, dialysis

2. Hyperkalemia: D50/insulin, kayexelate, calcium gluconate, dialysis.

3. Hypocalcemia: calcium gluconate, 1,25 VitD, dialysis to correct PO4

Criteria for dialysis:

1. Persistent hyperkalemia despite treatment

2. Rapidly rising or persistent hyperphosphatemia

3. Symptomatic hypocalcemia despite treatment

4. Fluid overload

5. Hyperuricemia

Annals of Oncology, 1996 7(6): 631-6