Infected Thoracic Aneurysm with Progressive Exudative Unilateral Pleural Effusion: A Case Report and Literature Review.

An infected aneurysm can be fatal; however, its early diagnosis is challenging because of the non-specificity of its symptoms. We herein report the case of a 90-year-old female patient with an infected aneurysm who presented with progressive, unilateral pleural effusion. A pleural fluid analysis revealed a mononuclear cell-predominant exudate with an elevated adenosine deaminase (ADA) level of 61.4 U/L. While these findings indicate that an infected aneurysm should be considered a possible cause of unilateral pleural effusion, the presence of elevated ADA, suggesting an unrelated condition, may lead to a misdiagnosis. Blood cultures and follow-up imaging are therefore necessary adjuncts to a comprehensive assessment of the patient's condition if an infected aneurysm is to be definitively diagnosed.