<prompt> A 63-year-old man with small cell carcinoma of the left mainstem bronchus begins chemotherapy. During the treatment period, he becomes febrile and develops a productive cough. The temperature is 38.7degC 103degF, respirations are 32 per minute and blood pressure is 12585 mm Hg. A CBC shows leukocytosis WBC 18,500mL. The patients cough worsens and he begins expectorating large amounts of foul smelling sputum. A chest X-ray shows a distinct cavity with an airfluid level distal to the tumor area. Which of the following is the most likely diagnosis?AtelectasisBronchiectasisGhon complexPulmonary abscess  <response>: The most common cause of pulmonary abscess is aspiration A cystic abscess contains purulent exudates and is contained by a fibrous wall. Abscess cavities are often paially filled with pus and air, which accounts for the X-ray finding of an air fluid level. None of the other choices present as cavitary lesions. Causes of Lung abscess: 1. ASPIRATION Decrease consciousness Alcoholics Hasty intake of food paicle MC 2. SEPTIC EMBOLISM Infective endocarditis 3. POST PNEUMONIA Staph. Aureus Klebsiella 4. OBSTRUCTION NEOPLASM Clinical features- High fever, productive cough, foul smelling sputum, paroxysms of cough are being brought on bychange of position 