Review Question - QID 107430

A patient with a history of alcoholism presenting with a fever and a cough, decreased oxygen saturation on room air, and increased tactile fremitus is likely due to aspiration pneumonia. This is most likely due to mixed anaerobes from the oral flora, one of them being fusobacterium.

Pneumonia is a common cause of respiratory pathology in both adults and children. In adults, the most common causes of community acquired pneumonia are Streptococcus pneumoniae, Mycoplasma pneumoniae, and Moraxella catarrhalis. In the healthcare setting, Pseudomonas and other gram negative organisms are more common. Stephylococcus aureus is especially prevalent as a cause of pneumonia after upper respiratory illnesses.

Mills et al. discuss the diagnosis and treatment of aspiration pneumonia in adults. They state that risk factors such as a history of stroke, dementia, gastroesophageal reflux disease, alcoholism, and tube-feeding requirements predispose patients to aspiration pneumonia with mixed anaerobes (most commonly from the oral flora). Due to the multiorganism nature of the pneumonia and commonly depressed status of the patients, it is also more common for aspiration pneumonia to present with complications such as pleural effusions and abscesses that may require surgical intervention. It most commonly presents in the right lower or right middle lobes.

Komiya et al. discuss aspiration pneumonia in their multicenter retrospective study. They report that patients diagnosed with aspiration pneumonia had a significantly worse survival than those with risk factors of aspiration alone (P=0.001), CT findings of aspiration alone (P=0.009) and neither (P<0.001). A multivariate analysis in this study indicated that aspiration pneumonia was independently associated with increased 30-day mortality (adjusted hazard ratio 5.690, P<0.001) after adjusting for other variables, including the category of pneumonia, performance status, the severity score (CURB-65) and treatment failure due to resistant pathogens.

Figure A shows an AP chest radiograph with a likely right middle lobe consolidation with an air fluid level, representing pneumonia complicated by an abscess.

Incorrect Answers:
Answer 1 and 5: Mycoplasma and Chlamydophila pneumoniae results in a interstitial pattern on chest radiographs and are common causes of community acquired pneumonia.

Answer 2: S. aureus is a common cause of pneumonia post upper respiratory infections.

Answer 4: S. viridans is normal flora of the mouth and could cause bacterial endocarditis after an invasive dental procedure in a patient with a prosthetic valve.