A 73-year-old man with a history of moderate chronic obstructive pulmonary disease comes to the emergency department with fever, malaise, night sweats, and a cough producing thick, yellowish sputum over the past 4 weeks. He has been using inhalers (tiotropium, formoterol, albuterol) as prescribed, but his symptoms have not improved. He smokes a half pack of cigarettes daily and has a 45-pack-year history. Medical history is also significant for hypertension, hyperlipidemia, Zenker diverticulum, and type 2 diabetes mellitus. He does not use alcohol or illicit drugs. Temperature is 37.7 C (99.8 F), blood pressure is 128/82 mm Hg, pulse is 94/min, and respirations are 16/min. Oxygen saturation is 95% on room air. Physical examination is within normal limits.
Laboratory results are as follows:
Chest x-ray reveals a right lower-lobe cavitary lesion with an air-fluid level.
What is the most appropriate next step in management of this patient?

Question

A 73-year-old man with a history of moderate chronic obstructive pulmonary disease comes to the emergency department with fever, malaise, night sweats, and a cough producing thick, yellowish sputum over the past 4 weeks.  He has been using inhalers (tiotropium, formoterol, albuterol) as prescribed, but his symptoms have not improved.  He smokes a half pack of cigarettes daily and has a 45-pack-year history.  Medical history is also significant for hypertension, hyperlipidemia, Zenker diverticulum, and type 2 diabetes mellitus.  He does not use alcohol or illicit drugs.  Temperature is 37.7 C (99.8 F), blood pressure is 128/82 mm Hg, pulse is 94/min, and respirations are 16/min.  Oxygen saturation is 95% on room air.  Physical examination is within normal limits.
Laboratory results are as follows:
 Chest x-ray reveals a right lower-lobe cavitary lesion with an air-fluid level.
What is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Lung abscess is defined as necrosis of lung tissue due to microbial infection. Most cases are polymicrobial in nature and occur due to aspiration of oral anaerobic and aerobic bacteria. Therefore, risk is greatest in those with altered sensorium (eg, alcohol/drug overdose, epilepsy) and conditions linked to impaired swallowing (eg, esophageal stricture/diverticula, previous stroke). Common pathogens include Peptostreptococcus, Fusobacterium, Prevotella, and Bacteroides. Opportunistic pathogens such as Pseudomonas, Nocardia, Aspergillus, and Mycobacteria may occur in those with systemic or pulmonary immunocompromise (eg, chronic lung disease, malignancy, diabetes mellitus). Manifestations typically include weeks or months of fever, cough with foul-smelling sputum, night sweats, and weight loss. Diagnosis is usually made when chest x-ray shows a cavitary infiltrate (often with an air-fluid level) in dependent portions of the lung (eg, superior portion of lower lobe). CT scan is sometimes required to rule out malignancy, to differentiate between abscess and empyema, and to confirm the diagnosis when chest x-ray is equivocal. chest x-ray CT scan Unlike other abscesses, lung abscesses do not require drainage and frequently respond to antibiotics. First-line therapy is ampicillin-sulbactam or a carbapenem; clindamycin is no longer recommended (except in those with beta-lactam allergy) due to risk of treatment-associated Clostridium difficile infection. Patients are typically treated until repeat chest x-ray is clear or shows a small, stable residual lesion. (Choice A) Bronchoscopy is typically not performed in patients with clinical and radiographic findings consistent with lung abscess. In addition, anaerobic sputum/bronchial cultures have low yield in the setting of lung abscess. Bronchoscopy is generally reserved for patients who do not respond to therapy or have an atypical presentation. (Choice C) Metronidazole is generally effective against anaerobic bacteria; however, it has no activity against the aerobic/microaerophilic bacteria that may be present in some lung abscesses. Metronidazole monotherapy is associated with a 50% treatment failure rate and is not recommended. However, it is sometimes used in combination with penicillin. (Choice D) Sputum stain for acid-fast bacilli to rule out tuberculosis may be required in atypical presentations. However, this patient has no risk factors for tuberculosis. His subacute symptoms, aspiration risk factor (Zenker diverticulum), and lower lobe cavitary lesion with an air-fluid level make lung abscess far more likely. (Choice E) Transesophageal echocardiogram is used to rule out endocarditis in cases of septic pulmonary emboli. However, this patient does not have a murmur, and septic emboli usually affect multiple lung areas. Educational objective: Lung abscess occurs in individuals with a predisposition to aspiration. It typically has an indolent presentation with fever, night sweats, weight loss, and cough with foul-smelling sputum. Chest x-ray generally reveals a cavitary lesion with an associated air-fluid level. First-line treatment is ampicillin-sulbactam or a carbapenem. __________ References: How important are anaerobic bacteria in aspiration pneumonia: when should they be treated and what is optimal therapy. (http://www.ncbi.nlm.nih.gov/pubmed/23398871)

A 73-Year-Old Man with a History of Moderate Chronic Obstructive