Spontaneous tumor lysis syndrome (STLS) during biopsy for burkitt lymphoma: a case report

Existing literature suggests that STLS is a very rare condition. In this case, the child experienced sudden onset of STLS towards the end of a biopsy, which was complicated by severe hyperkalemia and arrhythmia. Timely intervention using CVVHDF saved the patient’s life and restored function to organs damaged during this episode of STLS.

First reported by Cohen et al. in 1980, TLS is a life-threatening oncological emergency experienced by patients with hematological tumors [3]. TLS usually occurs 48–72 h after the start of chemotherapy and is most common in patients with acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma (NHL) [4, 5]. STLS occurs occasionally, with an incidence of about 1.08% of hematological malignancy patients [6]. Reported triggers include corticosteroid therapy, radiotherapy, anesthesia and fever [7‐11]. However, cases similar to ours, where STLS manifested during an operation but was successfully treated, are extremely rare worldwide.

The rapid lysis of tumor cells lead to the release of massive quantities of intracellular contents into the bloodstream, including anions, cations, proteins and nucleic acids. The release and subsequent catabolism of nucleic acids can result in hyperuricemia. In this case, crystals precipitate in the renal tubules as uric acid concentrations increase, which may lead to renal insufficiency or failure [12].

According to Cairo-Bishop’s definition of TLS in 2004, the laboratory criteria include: i) ≥ 2 abnormal serum values at presentation and ii) at minimum 25% increase or decrease in calcium, uric acid, potassium, or phosphorus levels either three days prior to the start of chemotherapy or within seven days following chemotherapy commencement [13]. The diagnostic criteria for clinical TLS are the same as laboratory TLS with one or more clinical complications, including renal insufficiency (serum creatinine ≥ 1.5 times the upper limit of normal), arrhythmias, seizures, or sudden death. In our case, the initial examination failed to diagnose laboratory TLS. However, when the patient suddenly developed arrhythmias, severe hyperkalemia, and hypocalcemia with preceding hyperuricemia during the biopsy operation, this met the clinical criteria of TLS diagnosis.

The mortality rate of TLS in hematological malignancies and solid tumors is 21.4% and 33%, respectively [5]. Thus, prevention, or at least early identification, of TLS is crucial. In 2010, the International TLS Expert Group formulated recommendations to define the potential risk of TLS from solid tumors and hematologic malignancies in children and adults. They defined three levels of risk based on the probability of TLS occurrence: low (1%); medium (1–5%) and high risk (5%)^[14]. Risk factors for TLS in tumor patients usually include disease types; tumor characteristics (high tumor load, rapid tumor growth, significant sensitivity to chemotherapy) and elevated baseline lactate dehydrogenase or uric acid levels [5, 14‐17]. In our case study: (1) pre-operative imaging evidence showed that the tumor had multi-organ infiltration and biochemical LDH was significantly raised, indicating a high tumor burden; (2) Abnormal metabolic functions resulted in high fever during operation, which can induce TLS; (3) The patient had hyperuricemia, in which uric acid deposition caused renal injury; (4) Mivacurium chloride, a non-depolarizing muscle relaxant, was used during the operation, as it has been suggested that depolarizing muscle relaxants can cause hyperkalemia [7, 11]. (5) The surgical biopsy of the tumor resulted in the destruction of tumor cells, prompting tumor lysis; (6) Further research into existing literature revealed that most intraoperative STLS occurred during abdominal closure, suggesting that changes in abdominal pressure could be a predisposing factor for TLS.

With regards to TLS, the adage “prevention is better than a cure” holds true. Hyperuricemia is one of the major risk factors associated with TLS, as it can cause AKI, which in turn increases the risk of mortality [2, 18]. Allopurinol is recommended for the prevention of low to medium-risk TLS, whereas urate oxidase is the preferred urate-lowering agent in high-risk patients [16, 17]. Furthermore, adequate hydration can improve intravascular volume; enhance renal perfusion and glomerular filtration; and further promote the excretion of uric acid, potassium and phosphorus, all reducing the risk of TLS. In this case, the tumor load was high, so prophylactic hydration was performed before surgery. However, the fluid infusion volume was still insufficient and the uric acid level was poorly controlled. Aggressive hydration is defined as excessive hydration with 2.5 (maximum 3) l/m2 of intravenous crystalloid per day to achieve a target urine volume of at least 4 ml/ (kg/h) [17].

Once TLS occurs, it is crucial to correct electrolyte abnormalities and administer CRRT if necessory [15]. Indications for CRRT in TLS patients are similar in patients with other causes of AKI, such as significant fluid overload; uremia; and severe electrolyte and metabolic disorders [5, 6, 19]. In this case, the patient had severe hyperkalemia during his biopsy operation, resulting in arrhythmia. Unfortunately, although the child rapidly received corrective treatments (including the injection of calcium gluconate, insulin, sodium bicarbonate), the outcome was poor. Given the poor effect associated with conservative treatment of hyperkalemia, hypocalcemia and acidosis, we opted to perform CVVHDF. Fortunately, this timely intervention caused the potassium level to decreased rapidly( 6 h after the start of CRRT) and resulted in restored kidney function following treatment. Thus, when severe hyperkalemia (potassium level ≥ 7 mmol/l) occurs in TLS, timely CRRT can potentially produce a good prognosis [17].