Examkin

Soru

Zorluk: OrtaPharmacologic Interventions

A 68-year-old man is hospitalized for altered mental status, generalized weakness, and constipation over the past 48 hours. He has a history of advanced squamous cell carcinoma of the lung. On physical examination, he is lethargic but arousable. Mucous membranes are extremely dry.

Initial laboratory studies show:
- Serum calcium: 14.8 mg/dL
- Serum albumin: 4.0 g/dL
- Blood urea nitrogen: 52 mg/dL
- Serum creatinine: 2.9 mg/dL (baseline 1.1 mg/dL)

The patient is immediately started on aggressive intravenous normal saline resuscitation. After receiving 3 liters of normal saline over the next 12 hours, his mental status improves slightly. A repeat serum calcium level is 13.5 mg/dL. He has clear lung fields and no peripheral edema. His urine output has been 80 mL/hr for the last 4 hours. Which of the following is the most appropriate next step in the pharmacologic management of this patient's hypercalcemia?

  1. Subcutaneous calcitoninCevap
  2. B
    Intravenous zoledronic acid
  3. C
    Intravenous furosemide
  4. D
    Intravenous hydrocortisone
  5. E
    Oral cinacalcet

Cevap

The most appropriate next step is to administer subcutaneous calcitonin, as it lowers serum calcium rapidly and is safe to use in the setting of acute kidney injury.
The correct answer is subcutaneous calcitonin. This patient is experiencing severe hypercalcemia of malignancy, which has led to profound dehydration and subsequent acute kidney injury (AKI). The initial standard of care is aggressive volume resuscitation with isotonic normal saline, which has been appropriately initiated. However, further pharmacologic intervention is required to safely lower the calcium level. Calcitonin acts rapidly (within 4 to 6 hours) to inhibit osteoclast activity and increase renal calcium excretion. Crucially, it is completely safe to administer in the setting of AKI. Although its effect is transient due to tachyphylaxis (usually diminishing after 48 hours), it provides an essential bridge for acute calcium control.

Adım Adım Çözüm

1
Identify the etiology and severity of the condition.
The patient has severe hypercalcemia of malignancy (likely PTHrP-mediated due to squamous cell carcinoma) accompanied by acute kidney injury from profound volume depletion.
Establishing the mechanism and complications dictates the safety profile required for pharmacotherapy.
2
Evaluate the patient's response to initial therapy.
Aggressive IV normal saline has modestly lowered the calcium level (from 14.8 to 13.5 mg/dL) and improved perfusion, but the patient remains significantly hypercalcemic.
Fluids alone are rarely sufficient for severe hypercalcemia; adjuvant pharmacotherapy must be added once volume is expanding.
3
Select the appropriate pharmacologic agent while observing contraindications.
Subcutaneous calcitonin is selected because it works rapidly and lacks nephrotoxicity, whereas bisphosphonates (like zoledronic acid) are absolutely contraindicated due to the acute kidney injury.
Avoidance of nephrotoxins prevents irreversible renal damage, while calcitonin provides the necessary immediate serum calcium reduction.

Anahtar Kavram

In patients with severe hypercalcemia of malignancy complicated by acute kidney injury, bisphosphonates are contraindicated. Subcutaneous calcitonin should be administered for rapid calcium lowering, often followed by denosumab for sustained management.
Bu soruyu puanla

Konular

Pharmacologic Interventions

Bu konudan daha fazla soru