Diffuse Alveolar Hemorrhage Caused by Warfarin after Rifampicin Discontinuation

Abstract

An 83-year-old man under warfarin therapy presented for assessment of prolonged prothrombin time and cough. High-resolution computed tomography findings of the chest showed diffuse alveolar hemorrhage. His international normalized ratio (INR) was 11.89. He had been treated with rifampicin for a persistent infection, but this had been discontinued about two months before admission. Rifampicin suppresses the anticoagulant activity of warfarin, which can lead to a need for increased doses of warfarin to achieve and maintain a therapeutic INR. More frequent INR monitoring is needed even after discontinuing rifampicin.

Figure 1

Chest X-ray findings on admission. Image shows alveolar opacity in both lungs, particularly in upper and middle lobes.

Figure 2

Chest computed tomography findings on admission. High-resolution computed tomography of the chest shows reticular opacity with bronchial-wall thickening and interlobular septal thickening in both lung fields.