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Difficulty: Very hardHematology and Oncology

A 68-year-old man is brought to the emergency department by his daughter due to worsening confusion, profound fatigue, and severe lower back pain over the past two weeks. He has a history of hypertension. Temperature is 37.1°C (98.8°F), blood pressure is 110/70 mmHg, pulse is 112/min, and respiratory rate is 16/min. Physical examination reveals dry mucous membranes and point tenderness over the L3 and L4 vertebrae. Neurologic examination shows no focal deficits, but the patient is lethargic and oriented only to name.

Laboratory studies show:
- Hemoglobin: 8.9 g/dL
- Platelet count: 140,000/mm³
- Leukocyte count: 4,500/mm³
- Serum calcium: 13.8 mg/dL
- Serum creatinine: 2.8 mg/dL (baseline 0.9 mg/dL)
- Blood urea nitrogen: 56 mg/dL
- Total protein: 10.2 g/dL
- Albumin: 3.1 g/dL

Arrange the following management and diagnostic steps in the most appropriate chronological sequence for this patient.

  1. 1Administer continuous intravenous hydration with isotonic saline
  2. 2Obtain serum protein electrophoresis, immunofixation, and free light chain assays
  3. 3Perform a whole-body low-dose computed tomography (CT) scan
  4. 4Perform a bone marrow aspiration and biopsy
  5. 5Initiate targeted induction chemotherapy (e.g., bortezomib, lenalidomide, dexamethasone)

Answer

The correct sequence prioritizes acute stabilization of severe hypercalcemia with intravenous fluids, followed by initial non-invasive laboratory diagnosis (protein electrophoresis), non-invasive skeletal staging (whole-body CT), definitive invasive diagnosis (bone marrow biopsy), and finally, targeted induction chemotherapy.
The correct chronological sequence reflects both emergency medicine principles and standard oncologic workflows. The patient has critical hypercalcemia and acute kidney injury necessitating immediate isotonic saline administration. Once stabilized, the diagnostic workup proceeds from non-invasive (serum protein electrophoresis and whole-body low-dose CT to establish CRAB criteria) to invasive (bone marrow biopsy to establish clonality and cytogenetics). Targeted chemotherapy is only appropriate after a complete diagnostic and prognostic evaluation is finished.

Step-by-Step Solution

1
Recognize the oncologic emergency (severe hypercalcemia and acute kidney injury) in the context of suspected malignancy.
Identify the need for immediate metabolic and hemodynamic stabilization.
A serum calcium level of 13.8 mg/dL with altered mental status is life-threatening and takes absolute clinical precedence over further diagnostic workup.
2
Identify the most likely underlying diagnosis based on the clinical picture (anemia, hypercalcemia, kidney injury, bone pain, and elevated protein gap).
Suspect Multiple Myeloma as the primary etiology.
This classic 'CRAB' presentation requires a highly specific, stepwise diagnostic algorithm starting with the least invasive tests.
3
Determine the correct sequence of the multiple myeloma diagnostic workup.
Prioritize non-invasive blood tests, then imaging, followed by invasive procedures.
Serum protein electrophoresis confirms the monoclonal protein. CT scans identify bone lesions. Bone marrow biopsy provides definitive cellular and cytogenetic confirmation.
4
Determine the precise timing for initiating definitive systemic therapy.
Place induction chemotherapy as the final step in the sequence.
Chemotherapy should only be started after accurate cytogenetic risk stratification from the bone marrow biopsy is available to guide regimen selection.

Key Concept

The management of suspected multiple myeloma presenting with an oncologic emergency requires immediate metabolic stabilization (IV fluids for hypercalcemia) prior to a stepwise diagnostic approach: non-invasive laboratory confirmation, imaging for skeletal involvement, invasive bone marrow biopsy, and finally systemic chemotherapy.
Estimated Time:2m 30s
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Topics

Hematology and Oncology

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