A 79-year-old man with metastatic prostate cancer is brought to the emergency department by his caretaker due to concern about his breathing. The patient takes a short-acting opioid every 4 hours and applies a transdermal fentanyl patch for malignant bone pain; the dose of the patch was increased 3 days ago due to inadequate pain control. The caretaker reports that the patient's breathing "has been strange" since this morning, but he has had no fever or cough. Temperature is 37.4 C (98.6 F), blood pressure is 112/78 mm Hg, pulse is 115/min, and respirations are 24/min. Oxygen saturation is 90% on room air. On physical examination, the patient is chronically ill-appearing and drowsy but arouses easily to voice. Bilateral pupils are small but reactive. The lungs are clear to auscultation with normal tidal air movement bilaterally. The patient continues to have significant pain with any repositioning. Chest x-ray reveals stable appearance of previously known blastic lesions in the thoracic spine and ribs but no acute abnormalities. ECG shows sinus tachycardia. Blood cell counts and urinalysis are normal. Which of the following is the most appropriate next step in management of this patient?

Question

A 79-year-old man with metastatic prostate cancer is brought to the emergency department by his caretaker due to concern about his breathing.  The patient takes a short-acting opioid every 4 hours and applies a transdermal fentanyl patch for malignant bone pain; the dose of the patch was increased 3 days ago due to inadequate pain control.  The caretaker reports that the patient's breathing "has been strange" since this morning, but he has had no fever or cough.  Temperature is 37.4 C (98.6 F), blood pressure is 112/78 mm Hg, pulse is 115/min, and respirations are 24/min.  Oxygen saturation is 90% on room air.  On physical examination, the patient is chronically ill-appearing and drowsy but arouses easily to voice.  Bilateral pupils are small but reactive.  The lungs are clear to auscultation with normal tidal air movement bilaterally.  The patient continues to have significant pain with any repositioning.  Chest x-ray reveals stable appearance of previously known blastic lesions in the thoracic spine and ribs but no acute abnormalities.  ECG shows sinus tachycardia.  Blood cell counts and urinalysis are normal.  Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Explanation: This elderly patient with metastatic cancer and malignant bone pain on chronic opioid therapy exhibits altered alertness and has vague respiratory symptoms. Pertinent vital sign abnormalities include sinus tachycardia, mild tachypnea (respirations ≥20/min), and mild hypoxemia (SaO₂ ≤92% on room air). With his elevated respiratory rate and normal tidal air movement, the patient's overall minute ventilation is likely to be normal; therefore, his hypoxemia is unlikely due to hypoventilation (eg, respiratory depression from opioids). These findings are concerning for an acute cardiopulmonary disease process leading to decreased oxygenation and increased respiratory drive. In a patient with malignancy, pulmonary thromboembolism or symptomatic pericardial effusion are worrisome and may not be apparent on chest x-ray. Therefore, further diagnostic evaluation (eg, CT pulmonary angiography, bedside echocardiogram) is warranted. Opioids can mask the symptoms of acute illness by blunting the respiratory response. A common cognitive error is to prematurely assume that an abnormal respiratory status is be a side effect of opioid therapy. However, the presence of tachypnea, increasing dyspnea, or respiratory distress should always alert clinicians and caregivers to a non-opioid-related underlying acute disease process. (Choice A) Opioid intoxication can produce somnolence and miosis. However, miosis may be seen with chronic opioid therapy due to the relative lack of pupillary tolerance; pinpoint pupils (<1 mm and nonreactive to light), not seen in this patient, are a more specific indicator of intoxication. In addition, naloxone reversal is not indicated for isolated mental status changes without significant hypopnea (respirations ≤8/min). Sudden opioid withdrawal may precipitate vomiting and aspiration.. (Choices B and E) Pain and alertness are not mutually exclusive; patients can experience significant pain despite a clouded sensorium. Because acute illness (eg, pulmonary embolism with hypoxemia) can cause altered mental status, opioid regimen adjustment should be postponed pending medical evaluation. Indeed, it may be appropriate to increase the opioid dosage (eg, if tachypnea/dyspnea is due to painful splinting or pulmonary metastases). (Choice D) Stimulants (eg, modafinil) are very occasionally used to counteract opioid-induced sedation in patients who desire greater wakefulness (eg, to interact with family at the end of life). However, this patient's altered mental status may be due to an acute illness, which should be evaluated and treated prior to managing his somnolence symptomatically. Educational objective: In patients receiving chronic opioid therapy, increased respiratory drive (eg, dyspnea, tachypnea) is abnormal and should alert clinicians and caregivers to an acute underlying non-opioid-related disease process.

A 79-Year-Old Man with Metastatic Prostate Cancer Is Brought to the Emergency