Pneumonia

Bacterial pneumonia usually follows aspiration of oropharyngeal flora into the lungs. Severe intoxication is associated with altered consciousness and a diminished cough reflex. Elevated ethanol levels can interfere with cilial function on the surface of respiratory epithelial cells. Most alcoholics also smoke cigarettes, which further impairs mucociliary defenses against infection of the respiratory tract. The most frequent bacterial causes of pneumonia in alcoholics include Streptococcus pneumoniae, anaerobes, aerobic gram-negative bacilli, and Haemophilus influenzae.

Standard diagnostic approaches are used to evaluate alcoholic patients who exhibit signs or symptoms of pneumonia. Organisms seen on sputum Gram stain often can help guide empiric antibiotic therapy. In addition to obtaining sputum and blood cultures, any significant pleural fluid visible on chest radiographs should be sampled for appropriate stains and cultured for aerobic and anaerobic organisms.

Because the severity of bacterial pneumonia is increased in alcoholics, hospitalization for parenteral antibiotic therapy is usually indicated. The length of hospital stay and the need for intensive care units are likely to be higher, and the expected mortality rate is greater than twice that for nonalcoholics.

Pneumococcal pneumonia

Streptococcus pneumoniae, or pneumococcus, remains the most common cause of both community-acquired bacterial pneumonia and bacterial meningitis in adults. Outbreaks of pneumococcal pneumonia have occurred among residents of shelters and prisons, where close proximity enhances the risk of transmission. Alcoholics have the usual signs and symptoms of pneumococcal pneumonia, including a sudden onset, often with a single shaking chill, fever, and subsequent productive cough. Secondary complications, including acute respiratory distress syndrome, empyema, and bacteremia, are common in alcoholics, particularly those with liver disease. Despite appropriate therapy, the reported overall mortality for adult bacteremic pneumococcal pneumonia increases from approximately 20% to >50% in patients with cirrhosis. The Advisory Committee on Immunization Practices recommends pneumococcal polysaccharide vaccine for all alcoholics. However, the antibody responses may be blunted, and the efficacy of the vaccine has been questioned in this high-risk population.

Current guidelines on the management of community-acquired pneumonia in alcoholic adults recommend either the empiric use of a respiratory fluoroquinolone such as moxifloxacin or levofloxacin, or the combination of a β-lactam agent such as ceftriaxone or ampicillin–sulbactam with a macrolide such as azithromycin. For less severe cases not requiring inpatient treatment, oral β-lactam agents available for outpatient use include high-dose amoxicillin and amoxicillin–clavulanate.

Anaerobic pneumonia

Anaerobic oropharyngeal bacteria, including peptostreptococci, Fusobacterium spp., and Prevotella melaninogenica, are commonly involved in aspiration pneumonia and can cause lung abscess and empyema. Intoxication interferes with several host defenses against aspiration of oropharyngeal contents. Elevated circulating ethanol levels can disrupt the coordinated beating of cilia on respiratory epithelium and thus impair mucociliary clearance of inhaled or aspirated organisms. Inebriation also can be associated with diminished gag and cough reflexes. Alcoholics frequently have severe periodontal disease, which can increase the number of anaerobic organisms in the aspirated inoculum. Clinical signs and symptoms of anaerobic pneumonia commonly progress slowly over weeks or months before patients present with malaise, low-grade fever, cough producing foul-smelling sputum, and/or weight loss. Recommended therapy includes a β-lactam/β-lactamase inhibitor such as piperacillin–tazobactam, ampicillin–sulbactam, or amoxicillin–clavulanate. Alternatively, a carbapenem may be used such as ertapenem or meropenem. Clindamycin is indicated for anaerobic pleuropulmonary infections in patients who are allergic to penicillin.

Gram-negative pneumonia

Gram-negative bacilli such as Klebsiella pneumoniae and Enterobacter spp. are more likely to colonize the oropharynx and cause pneumonia in alcoholics than in nonalcoholics. The combination of bloody sputum and an upper lobe infiltrate with a bulging fissure that has been classically associated with Klebsiella pneumonia is rarely seen today. Mortality with gram-negative bacillary pneumonia exceeds that of pneumococcal pneumonia and increases further if neutropenia is also present. For pneumonia due to Enterobacteriaceae, recommendations include either a third-generation cephalosporin such as ceftriaxone, a fourth-generation cephalosporin such as cefepime, or a carbapenem such as ertapenem or meropenem. If the pathogen is an extended-spectrum β-lactamase producer, a carbapenem should be used. Alternative antimicrobials include β-lactam/β-lactamase inhibitor combinations or a fluoroquinolone.

When Pseudomonas is suspected or identified as the causative agent, an antipseudomonal β-lactam such as piperacillin, ceftazidime, cefepime, aztreonam, imipenem, or meropenem should be used in combination with either an antipseudomonal fluoroquinolone (ciprofloxacin or levofloxacin) or an aminoglycoside such as gentamicin. An alternative regimen would be an aminoglycoside plus the antipseudomonal fluoroquinolone.

The coccobacillus H. influenzae

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