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 125/85 mm Hg. A CBC shows leukocytosis (WBC = 18,500/mL). The patient's cough worsens and he begins expectorating large amounts of foul smelling sputum. A chest X-ray shows a distinct cavity with an air/fluid level distal to the tumor area. Which of the following is the most likely diagnosis?

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 (M/C) 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