A 46-year-old man is brought to the emergency department 30 minutes after being found intoxicated in a park. The patient reports a 10-day history of fevers, night sweats, weight loss, and productive cough with foul-smelling sputum. He drinks 1 or 2 pints of vodka daily and has been hospitalized multiple times for intoxication. Temperature is 38.9 C (102 F), blood pressure is 110/65 mm Hg, pulse is 102/min, and respirations are 22/min. Lung auscultation reveals coarse crackles over the right lower lobe. Heart sounds are normal with no murmurs. Laboratory results show an elevated leukocyte count. Chest x-ray reveals a cavitary lesion with an air-fluid level in the superior segment of the right lower lobe of the lung. Which of the following is the most likely cause of this patient's lung findings?

Question

A 46-year-old man is brought to the emergency department 30 minutes after being found intoxicated in a park.  The patient reports a 10-day history of fevers, night sweats, weight loss, and productive cough with foul-smelling sputum.  He drinks 1 or 2 pints of vodka daily and has been hospitalized multiple times for intoxication.  Temperature is 38.9 C (102 F), blood pressure is 110/65 mm Hg, pulse is 102/min, and respirations are 22/min.  Lung auscultation reveals coarse crackles over the right lower lobe.  Heart sounds are normal with no murmurs.  Laboratory results show an elevated leukocyte count.  Chest x-ray reveals a cavitary lesion with an air-fluid level in the superior segment of the right lower lobe of the lung.  Which of the following is the most likely cause of this patient's lung findings?

Quizplus · Accepted Answer

11ec160b_38a0_66b1_9249_255a7ac37cfa_MD0001_00 This patient has a cavitary lesion with an air-fluid level on chest x-ray, raising strong suspicion for lung abscess. Most cases of lung abscess present with several weeks of fever, malaise, weight loss, and leukocytosis. Cough with copious production of greenish, foul-smelling sputum is also common. Lung abscess usually forms due to the aspiration of oropharyngeal bacteria. Risk is greatest in patients with ≥1 of the following: Most lung abscesses are polymicrobial and feature a mixture of oral anaerobic (eg, Fusobacterium, Peptostreptococcus, Bacteroides) and aerobic bacteria. Infections are most common in dependent areas of the right lung because the right bronchus is straighter than the left bronchus; aspiration that occurs in the upright position usually leads to an abscess in the basal segment of the right lower lobe, whereas aspiration that occurs while supine often causes abscess in the posterior segment of the right upper lobe or the superior segment of the right lower lobe. (Choice A) Aspiration of gastric acid causes chemical pneumonitis (acidic damage to alveoli), which typically results in severe dyspnea, hypoxia, and diffuse pulmonary infiltrates within hours of an aspiration event. It does not usually present with weeks of productive cough or a cavitary lesion. (Choice C) Right-sided infective endocarditis may result in the development of multiple lung abscesses due to septic emboli. It is most often seen in intravenous drug use. This patient with alcohol use disorder has a single lung abscess in a dependent portion of the right lung, which is most likely due to aspirated oropharyngeal bacteria. (Choice D) Cavitary tuberculosis (TB) is usually due to reactivated (not primary) mycobacterial infection. In addition, TB cavities do not typically have air-fluid levels and are most common in the upper portions of the lung. (Choice E) An aspergilloma (fungal ball) usually colonizes an already existing lung cavity, typically in the presence of TB, lung cancer, or chronic obstructive pulmonary disease. Aspergillomas generally occur in the upper lobes. Unlike chronic aspergillosis, simple aspergillomas are not associated with systemic symptoms (eg, fever, hemoptysis). Educational objective: Lung abscess usually occurs in individuals with episodes of impaired consciousness (eg, alcohol/substance use disorder, dementia) or decreased ability to swallow (eg, esophageal strictures). They are generally caused by aspiration of anaerobic and aerobic bacteria from the oral cavity into the lower respiratory tract.

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