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Difficulty: EasyHematology and Oncology

A 55-year-old man is admitted to the hospital after a lymph node biopsy confirmed the diagnosis of a highly aggressive non-Hodgkin lymphoma. He is scheduled to receive his first cycle of multi-agent chemotherapy in 2424 hours. He currently has no acute complaints. Vital signs are within normal limits. Laboratory studies reveal the following:

Laboratory TestResultReference Range
Hemoglobin11.2 g/dL11.2 \text{ g/dL}13.5−17.5 g/dL13.5-17.5 \text{ g/dL}
Leukocyte count45,000/mm345,000/\text{mm}^34,500−11,000/mm34,500-11,000/\text{mm}^3
Platelet count140,000/mm3140,000/\text{mm}^3150,000−400,000/mm3150,000-400,000/\text{mm}^3
Serum creatinine0.9 mg/dL0.9 \text{ mg/dL}0.6−1.2 mg/dL0.6-1.2 \text{ mg/dL}
Uric acid9.8 mg/dL9.8 \text{ mg/dL}4.0−8.5 mg/dL4.0-8.5 \text{ mg/dL}
Lactate dehydrogenase (LDH)1,500 U/L1,500 \text{ U/L}140−280 U/L140-280 \text{ U/L}

Which of the following is the most appropriate next step in management to prevent acute renal complications in this patient?

  1. Initiate aggressive intravenous hydration and administer allopurinolAnswer
  2. B
    Administer oral calcium carbonate
  3. C
    Initiate prophylactic broad-spectrum intravenous antibiotics
  4. D
    Schedule immediate prophylactic hemodialysis
  5. E
    Withhold interventions and monitor serum electrolytes every 6 hours

Answer

Initiate aggressive intravenous hydration and administer allopurinol
The correct answer is to initiate aggressive intravenous hydration and administer allopurinol. This patient has a highly aggressive lymphoma with a high tumor burden, as evidenced by significantly elevated baseline lactate dehydrogenase (LDH) and uric acid levels. He is at very high risk for tumor lysis syndrome (TLS) once multi-agent chemotherapy is initiated. TLS results from the massive destruction of tumor cells, leading to the rapid release of intracellular contents, including potassium, phosphate, and nucleic acids (which are metabolized into uric acid). The precipitation of uric acid and calcium-phosphate crystals in the renal tubules can cause severe acute kidney injury. Therefore, the standard of care for high-risk patients is prophylaxis with aggressive intravenous hydration to maintain robust urine output and the administration of a xanthine oxidase inhibitor (allopurinol) or a recombinant urate oxidase (rasburicase) to lower serum uric acid levels before chemotherapy begins.

Step-by-Step Solution

1
Evaluate the patient's clinical presentation and baseline laboratory values.
The patient has a highly aggressive lymphoma with markedly elevated baseline uric acid and LDH.
These findings indicate a high tumor burden and rapid cellular turnover.
2
Identify the primary risk associated with initiating multi-agent chemotherapy in this specific setting.
The patient is at exceptionally high risk for developing tumor lysis syndrome (TLS).
Chemotherapy will cause massive lysis of tumor cells, releasing intracellular contents (potassium, phosphate, and nucleic acids) into the systemic circulation, which can precipitate acute kidney injury.
3
Determine the most appropriate prophylactic intervention to prevent TLS-induced renal failure.
Aggressive intravenous hydration and a uric acid-lowering agent (such as allopurinol or rasburicase) must be started.
Intravenous fluids maintain high urine output to flush out metabolites, while allopurinol inhibits xanthine oxidase, preventing the formation of uric acid from released nucleic acids.

Key Concept

Patients with bulky, rapidly proliferating tumors (e.g., high-grade non-Hodgkin lymphoma, acute leukemia) are at high risk for tumor lysis syndrome when starting chemotherapy. Prophylaxis with aggressive intravenous hydration and allopurinol (or rasburicase) is essential to prevent acute uric acid nephropathy and subsequent renal failure.
Estimated Time:1m 0s
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Topics

Hematology and Oncology

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