A 65-year-old undomiciled man presents to your emergency department with complaints of fever, productive cough, and shortness of breath. He has a 40 pack-year history of smoking and daily alcohol consumption. His chest radiograph demonstrates a right upper lobe lung infiltrate with an air-fluid level. What is the most likely etiology for this finding?

Klebsiella pneumoniae:

Gram-negative encapsulated organism. Patients with klebsiella pneumonia commonly present with shaking chills, cyanosis, pleuritic chest pain, and a productive cough with characteristic currant-jelly sputum. Chest radiography reveals an infiltrate that is often in the upper lobes (most commonly the right) and is associated with a bulging fissure. If untreated, the infiltrate will progress into a necrotizing lesion with air-fluid levels, and can ultimately lead to development of an empyema.

Explanation:

The old man is sick with different symptoms. As a result, he must be diagnosed and examined to know the actual cause of the illness. This can be investigated by conducting a radiography test to check it there is any shrinkage in his organs such as lungs. Therefore, it is essential to conduct the test in order to reveal the findings.