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Difficulty: Very hardHematology and Oncology

A 39-year-old man is evaluated in the hospital for the sudden onset of fever and progressive shortness of breath. He was admitted 11 days ago with a diagnosis of acute promyelocytic leukemia and was subsequently started on induction therapy with all-trans retinoic acid and arsenic trioxide. Over the past 24 hours, he has gained 4.5 kg (9.9 lb) and developed a persistent cough. His temperature is 38.8°C (101.8°F), blood pressure is 105/65 mm Hg, pulse is 114/min, and respirations are 26/min. Pulse oximetry shows 87% on room air. Physical examination reveals jugular venous distention and bilateral crackles at the lung bases. Laboratory studies show a leukocyte count of 28,000/mm³ (up from 3,200/mm³ at admission), a hemoglobin of 8.2 g/dL, and a platelet count of 45,000/mm³. A chest radiograph demonstrates bilateral interstitial opacities and moderate pleural effusions. He is currently receiving prophylactic fluconazole and acyclovir. Which of the following is the most appropriate next step in management?

  1. Administer intravenous dexamethasoneAnswer
  2. B
    Discontinue all-trans retinoic acid
  3. C
    Initiate intravenous cefepime and vancomycin
  4. D
    Administer intravenous furosemide
  5. E
    Perform therapeutic leukapheresis

Answer

Administer intravenous dexamethasone
The most appropriate next step in management is administering intravenous dexamethasone. This patient is presenting with classic signs of differentiation syndrome (formerly known as retinoic acid syndrome), a life-threatening complication of induction therapy for acute promyelocytic leukemia (APL) using all-trans retinoic acid (ATRA) or arsenic trioxide. As the malignant promyelocytes are forced to differentiate into mature neutrophils, they release massive amounts of inflammatory cytokines (such as IL-1, IL-6, and TNF-alpha). This leads to a severe systemic inflammatory response and capillary leak syndrome. Clinically, this manifests with unexplained fever, significant weight gain, respiratory distress, pulmonary infiltrates, and pleural or pericardial effusions, typically occurring within the first three weeks of therapy. Because this condition can rapidly progress to acute respiratory distress syndrome (ARDS), multi-organ failure, and death, the standard of care is to initiate high-dose intravenous dexamethasone immediately upon clinical suspicion. Delaying corticosteroids for further diagnostic workup significantly increases mortality.

Step-by-Step Solution

1
Analyze the patient's underlying diagnosis and timeline of recent interventions.
The patient has acute promyelocytic leukemia (APL) and began induction therapy with all-trans retinoic acid (ATRA) and arsenic trioxide 11 days ago.
Establishing the pharmacological context is essential, as APL treatments have unique, highly specific toxicities.
2
Evaluate the acute clinical presentation and objective findings.
The patient exhibits a new-onset fever, profound rapid weight gain, respiratory distress, hypoxia, and radiographic evidence of pulmonary infiltrates and pleural effusions.
This specific constellation of symptoms points to a systemic capillary leak syndrome rather than a simple localized infection.
3
Synthesize the timeline and symptoms to form a diagnosis.
The presentation is classic for Differentiation Syndrome (formerly ATRA syndrome), which typically occurs 2 to 21 days after initiating APL induction therapy.
Differentiating leukemic promyelocytes release massive amounts of inflammatory cytokines, causing widespread endothelial damage.
4
Determine the most appropriate immediate therapeutic intervention.
Intravenous dexamethasone must be administered immediately.
High-dose corticosteroids rapidly suppress the inflammatory cytokine cascade and are the only definitive initial treatment to prevent progression to fatal acute respiratory distress syndrome.

Key Concept

Differentiation syndrome is a potentially fatal complication of APL therapy presenting with fever, respiratory distress, and weight gain; it must be recognized clinically and treated immediately with high-dose dexamethasone.
Estimated Time:1m 30s
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Topics

Hematology and Oncology

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