Q; 76 year old male with chronic atrial fibrillation admitted to ICU with shortness of breath. Patient is chronically on amiodarone. CXR is consistent with bacterial pneumonia vs amiodarone toxicity. Which one test may differentiate between bacterial pneumonia and amiodarone toxicity?


Answer:  KL-6

KL-6 gets secreted by proliferating type II pneumocytes. KL-6 is not specific for amiodarone toxicity but it is a sensitive marker in various interstitial lung diseases. KL-6 is a good test for patients who are chronically on amiodarone but develop other disease process like bacterial pneumonia, CHF, or even lung cancer. Reading it with diagnostic tools of other disease markers make it a good test to judge the relative role of amiodarone toxicity in patient's pathology.


References:

1. Endoh Y, Hanai R, Uto K, et al. KL-6 as a potential new marker for amiodarone-induced pulmonary toxicity. Am J Cardiol 2000; 86:229. 

2. Kohno N, Yokoyama A, Kondo K. KL-6 as a serum marker for amiodarone-induced pulmonary toxicity. Intern Med 2000; 39:1004. 

3. Bernal Morell E, Hernández Madrid A, Marín Marín I, et al. [Multiple pulmonary nodules and amiodarone. KL-6 as a new diagnostic tool]. Rev Esp Cardiol 2005; 58:447.