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Difficulty: HardHematology and Oncology

A 72-year-old man is brought to the emergency department by his daughter due to progressive lethargy, severe constipation, and deep lower back pain over the past week. He has a history of chronic obstructive pulmonary disease (COPD) and heart failure with preserved ejection fraction. The patient's brother is his legally appointed healthcare proxy, but the daughter is currently present and demands immediate aggressive interventions.

Upon arrival, a triage nurse accidentally administers 1 liter of 5% Dextrose in water (D5W) instead of the ordered isotonic saline. The daughter becomes furious upon realizing this and demands the nurse be fired immediately.

Temperature is 37.1°C (98.8°F), blood pressure is 115/75 mmHg, pulse is 105/min, and respirations are 16/min. Mucous membranes are dry, and he has diminished skin turgor. Neurologic examination reveals confusion and disorientation. Chest X-ray shows hyperinflated lungs. Lung auscultation reveals mild bilateral basilar crackles, which are unchanged from his baseline exams.

Laboratory studies are as follows:

TestResultReference Range
Hemoglobin8.9 g/dL13.5-17.5 g/dL
Leukocyte count6,500/mm³4,500-11,000/mm³
Platelet count180,000/mm³150,000-400,000/mm³
Serum calcium14.1 mg/dL8.4-10.2 mg/dL
Blood urea nitrogen48 mg/dL7-20 mg/dL
Serum creatinine2.5 mg/dL0.7-1.3 mg/dL
Total protein10.2 g/dL6.0-8.0 g/dL
Albumin3.4 g/dL3.5-5.5 g/dL
Thyroid-stimulating hormone (TSH)0.2 µU/mL0.4-4.0 µU/mL
Free T40.8 ng/dL0.9-1.7 ng/dL

A urine culture obtained two days ago at an outpatient clinic has just resulted, growing >100,000 CFU/mL of *Escherichia coli* that is sensitive to nitrofurantoin and cephalexin, but resistant to ampicillin.

Which of the following is the most appropriate next step in the management of this patient's acute condition?

  1. Initiation of aggressive intravenous isotonic saline hydrationAnswer
  2. B
    Initiation of oral levothyroxine therapy
  3. C
    Administration of intravenous piperacillin-tazobactam
  4. D
    Administration of systemic corticosteroids and nebulized albuterol
  5. E
    Recommendation of immediate disciplinary action and suspension for the triage nurse

Answer

The most appropriate next step in management is the initiation of aggressive intravenous isotonic saline hydration to treat the severe hypercalcemia.
The patient is presenting with a classic constellation of symptoms for multiple myeloma (hypercalcemia, renal failure, anemia, and bone pain). His severe hypercalcemia (14.1 mg/dL) is a medical emergency that causes osmotic diuresis, leading to profound volume depletion. The most critical initial step in managing severe hypercalcemia (>14 mg/dL) is aggressive intravenous hydration with isotonic saline. This rapidly restores intravascular volume, dilutes serum calcium, and promotes urinary calcium excretion.

Step-by-Step Solution

1
Analyze the patient's clinical presentation and laboratory findings.
The patient has a large protein gap (Total protein 10.2 - Albumin 3.4 = 6.8 g/dL of globulins), normocytic anemia, acute kidney injury, bone pain, and severe hypercalcemia (14.1 mg/dL).
These combined findings are highly suggestive of Multiple Myeloma presenting with a hypercalcemic crisis.
2
Determine the immediate life-threatening physiological derangement.
Severe hypercalcemia (> 14 mg/dL) is causing the patient's acute lethargy, confusion, constipation, and severe volume depletion (dry mucous membranes, diminished turgor).
Hypercalcemia induces nephrogenic diabetes insipidus, leading to profound polyuria, systemic dehydration, and a vicious cycle of worsening hypercalcemia due to decreased renal calcium clearance.
3
Identify the standard first-line treatment for this oncologic emergency.
Aggressive intravenous hydration with isotonic saline is required.
Isotonic saline rapidly restores intravascular volume, dilutes serum calcium, and promotes loop of Henle calcium excretion, making it the most critical initial intervention.

Key Concept

The initial management of severe symptomatic hypercalcemia of malignancy requires immediate, aggressive intravenous hydration with isotonic saline to restore volume and increase renal calcium excretion.
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Topics

Hematology and Oncology

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