A 74-year-old Caucasian female is brought to the physician's office by her daughter because she has been coughing a lot for the past four weeks. Her cough is present throughout the day, and is most prominent at nighttime. She easily gets "out of breath" while walking around the house. She denies fevers, rigors, or sputum production. She has a past medical history of hypertension, atrial fibrillation, congestive heart failure with an ejection fraction of 35%, history of ventricular tachycardia, hypothyroidism, and vascular dementia. Her daily medications include aspirin, metoprolol, furosemide, levothyroxine, amiodarone, and multivitamins. She is allergic to ACE inhibitors and penicillin. On examination, her temperature is 37.2C (99F), blood pressure is 110/82 mmHg, heart rate is 82/min, and respiratory rate is 20/min. Her mucous membranes are moist. There is no evidence of jugular venous distention. The lung examination reveals equal and normal air entry on both sides, with fine end inspiratory crackles heard at both the lung bases. Cardiovascular examination reveals a regular heart rhythm with no evidence of S3 gallop or murmurs. The rest of her physical examination is unremarkable. An initial chest x-ray reveals the presence of a normal cardiac silhouette. There is no evidence of pleural effusions. There are diffuse interstitial opacities seen bilaterally in the lower lung fields. Which of the following is the most appropriate next step in her management?

Question

A 74-year-old Caucasian female is brought to the physician's office by her daughter because she has been coughing a lot for the past four weeks.  Her cough is present throughout the day, and is most prominent at nighttime.  She easily gets "out of breath" while walking around the house.  She denies fevers, rigors, or sputum production.  She has a past medical history of hypertension, atrial fibrillation, congestive heart failure with an ejection fraction of 35%, history of ventricular tachycardia, hypothyroidism, and vascular dementia.  Her daily medications include aspirin, metoprolol, furosemide, levothyroxine, amiodarone, and multivitamins.  She is allergic to ACE inhibitors and penicillin.  On examination, her temperature is 37.2C (99F), blood pressure is 110/82 mmHg, heart rate is 82/min, and respiratory rate is 20/min.  Her mucous membranes are moist.  There is no evidence of jugular venous distention.  The lung examination reveals equal and normal air entry on both sides, with fine end inspiratory crackles heard at both the lung bases.  Cardiovascular examination reveals a regular heart rhythm with no evidence of S3 gallop or murmurs.  The rest of her physical examination is unremarkable.  An initial chest x-ray reveals the presence of a normal cardiac silhouette.  There is no evidence of pleural effusions.  There are diffuse interstitial opacities seen bilaterally in the lower lung fields.  Which of the following is the most appropriate next step in her management?

Quizplus · Accepted Answer

Explanation: The patient has a clinical presentation consistent with the development of amiodarone-induced pulmonary toxicity. Amiodarone is a commonly used antiarrhythmic drug for the treatment of ventricular and supraventricular tachyarrhythmias. Prolonged treatment with amiodarone is associated with a variety of adverse effects including photosensitivity, skin discoloration, bone marrow suppression, thyroid dysfunction, abnormal liver function tests, and pulmonary toxicity. Of all the above, pulmonary toxicity is the most serious adverse effect that is responsible for most of the deaths associated with amiodarone therapy. Pulmonary toxicity with amiodarone can be seen in the form of chronic interstitial pneumonitis, organizing pneumonia, acute respiratory distress syndrome, and rarely with a solitary pulmonary mass. Chronic interstitial pneumonitis is the most common presentation of amiodarone-induced pulmonary toxicity. It is characterized by the presence of nonproductive cough, fever, pleuritic chest pain, weight loss, dyspnea on exertion and a focal or diffuse interstitial opacity on the chest radiograph. It is usually seen after months to years of amiodarone therapy, especially in patients who are on higher maintenance doses (more than 400 mg/day). It is a cumulative dose effect, and the serum amiodarone levels are usually within the normal range in these patients. The chest radiograph may reveal the presence of diffuse or focal interstitial or alveolar opacities. Discontinuation of amiodarone is the mainstay of treatment for amiodarone-induced pulmonary toxicity. Corticosteroids can be used in patients with severe or life-threatening pulmonary disease. The prognosis is usually good in most cases, and majority of patients either stabilize or improve after the complete withdrawal of the drug. (Choices B and C) Based on the clinical presentation and chest radiographic findings, the patient's symptoms are unlikely to be from congestive heart failure exacerbation (absence of cardiomegaly, cephalization of pulmonary vessels, and pleural effusions on the chest radiograph). Therefore, increasing the dose of Lasix or reducing the dose of beta-blocker is not indicated at this point. (Choice D) Increasing the dose of metoprolol would have no effect on the course of amiodarone-induced pulmonary toxicity or chronic interstitial pneumonitis. Educational Objective: Prolonged therapy with amiodarone can cause a serious and potentially fatal pulmonary disease. Its treatment primarily consists of complete withdrawal of amiodarone. Corticosteroids can be used in patients with severe or life-threatening pulmonary disease.

A 74-Year-Old Caucasian Female Is Brought to the Physician's Office By