Trepopnea Due to Amiodarone-Induced Diffuse Alveolar Hemorrhage

Discussion

We report a case of trepopnea associated with amiodarone-induced diffuse alveolar hemorrhage. An early accumulative dose of 6 g was sufficient to cause interstitial disease, but hemoptysis with severe anemia and respiratory failure arose at 24 g. The most known side effect of amiodarone use is chronic fibrosing alveolitis. Acute lung toxicity is rare, commonly taking the form of an acute or subacute interstitial pneumonitis, but early alveolar hemorrhage has been also reported. Diffuse hemorrhage may lead to misdiagnosis. The symptoms and radiographic findings were initially misinterpreted as acute heart failure in this case. When trepopnea is present in patients with heart failure, it usually occurs in the left recumbent position and they prefer the right lateral decubitus position. The patient lies with the more affected lung down. It seems a self-protecting mechanism to augment cardiac output and to attenuate the imbalance of cardiac autonomic nervous activity.³ Inversely, this patient had dyspnea in the left, which could help to differentiate acute heart failure from other conditions. Computed tomography scan (see Fig. 1) seemed to show the left lung more affected. Similarly, asthenia, mild fever, and dyspnea may be mistaken for cancer or infection. Of note, the influence of coexistent anticoagulants has been noted as a problem in all of the previous reports. The temporal sequence of data suggests that amiodarone was the essential cause in this case. The probability of an adverse drug reaction can be measured by the Naranjo et al scale.⁴ Briefly, it consists of 7 items: temporal sequence, known adverse drug reaction, alternative explanation, adverse drug reaction evidence, laboratory tests, improvement after withdrawal, and worsening with reintroduction. The likelihood of a drug reaction is improbable when the score is < 1 point, possible when the score is 1–4 points, probable when the score is 5–8 points, and definitive when the score is 9–10. This case fulfilled 9 points for amiodarone. The findings detected by computed tomography suggested initial amiodarone toxicity in the interstitium, before the alveolar damage, which could not be attributed to anticoagulation. In addition, whereas acenocoumarol was maintained, the first discontinuation of amiodarone was followed by improvement until reintroduction. Although anticoagulation was reverted at admission, symptoms continued. Otherwise, previous antiplatelet therapy was given without hemoptysis. Histology showed exudative changes, and prescription of prednisone treated the condition.