A semi-retired man, 68 years of age, presents one Sunday morning to the emergency department with malaise, fever, productive cough, and right pleuritic chest pain of less than 24 hours duration. He has been active, works as a custodian, has never been hospitalized, takes no medications, and does not regularly see a physician. On review of systems, the patient states that he gave up smoking years ago, has a mild chronic cough and morning sputum production, and has noted mild dyspnea on exertion for the past six months. He drinks only beer, never after work, but every Saturday afternoon he likes to take a six-pack out into the backyard, where he relaxes in his lounge chair. When asked whether there was anything different about the Saturday before the onset of the illness, his wife relates that he consumed two six-packs and failed to come in that evening. She found him later, after dark, asleep in his lounge chair, and helped him in to bed. He awoke this morning with fever and chills. On exam, the patient's temperature is 102.6°F, blood pressure 154/80 mm Hg, pulse 94 beats per minute, and respiration 20 breaths per minute. He is alert, with signs of mild emphysema and crackles audible over the right lower posterolateral chest. The chest x-ray shows patchy alveolar opacification in the right lower lobe and slight cardiomegaly.

The working diagnosis here is CAP, likely caused by S. pneumoniae or H. influenzae, as the patient has no prodromal upper respiratory symptoms to suggest viral or mycoplasma infection.

Why is this happening now? COPD/chronic bronchitis appears to have developed in recent years. Such patients have damaged, poorly functioning mucociliary epithelium and rely on compensatory cough to promote tracheobronchial clearance. Moreover, they often have colonization with pneumococcus and H. influenzae. An additional risk factor in this patient may be mild heart failure with ambient alveolar edema in the basal segments of the lower lungs. Excessive beer consumption the evening before onset of illness made him somnolent and suppressed his cough reflex, thus rendering him vulnerable to aspiration and retention of upper tract secretions (if not gastroesophageal reflux and aspiration). Encumbered by alveolar edema, and perhaps impaired by the metabolic effects of alcohol, pulmonary macrophages in the basal segment of the right lung were simply overwhelmed.

What is the best site of care and treatment for this patient? While he does not meet the criteria for ICU admission, his age, comorbidities, degree of illness, and social situation taken together suggest the need for hospital admission, parenteral antibiotic therapy, and close observation, anticipating a short hospital stay. He was treated with a ß -lactam and macrolide, improved rapidly, and was discharged day 3 on a matching oral regimen, to complete a 10-day course of therapy.

What preventive measures were taken to reduce the risk of this happening again? The 20-valent pneumococcal conjugate vaccine (PCV20) (Prevnar 20) was administered prior to discharge and arrangements were made for primary care follow-up. The patient and his wife were educated regarding the need for yearly influenza vaccination. The role of alcohol was discussed, as well as the importance of keeping the Saturday afternoon beer consumption within clearly defined limits.

A man, 73 years of age, with a history of coronary disease, COPD, benign prostatic hyperplasia, and type 2 diabetes is hospitalized on transfer from an assisted-living facility because of weakness, loss of appetite, and low-grade fever. He had been admitted elsewhere for similar symptoms six months earlier and was diagnosed with urinary tract infection and treated with an unknown antibiotic. On evaluation, the patient's temperature is 37.6°C (99.8°F) and his other vital signs are stable; his exam is unremarkable. The WBC is normal, and the urinalysis shows pyuria. The admission chest x-ray shows hyperlucent lung fields and flattened diaphragms indicative of emphysema, but no infiltrate. Empiric treatment with a first-generation cephalosporin is begun for presumed urinary tract infection. The patient has no further fever, and his appetite and strength improve over the next 48 hours. He does have periods of mild agitation and insomnia, which are treated with a benzodiazepine at bedtime.

On the fourth day, as plans for discharge were in place, the patient appears worse, with a cough and a temperature of 38°C (100.4°F). A repeat chest x-ray shows a small focal opacity in the left upper lobe, thought to represent "aspiration." No change in antibiotics is made, and he is observed. Over the next 36 hours, the patient's condition worsens; he now has a cough productive of purulent sputum, fever (102°F to 103°F), shortness of breath, and tachypnea. A follow-up chest x-ray now shows an extensive opacification/infiltrate in the left upper lobe, with signs suggestive of either central cavitation or consolidation high-lighting emphysematous blebs.

In this elderly, somewhat debilitated man with chronic lung disease, who may be at risk of aspiration, a rapidly progressive, necrotizing (hospital-acquired) pneumonia developed while he was being treated with an oral cephalosporin for urinary tract infection, and receiving a nightly sedative medication for sleep.

What are the etiologic considerations and how should the patient be managed? Within days of admission to a hospital, and especially if treated with antibiotics, many patients develop nasopharyngeal colonization by hospital flora (e.g. gram-negative bacilli and occasionally S. aureus). When pneumonia supervenes, it reflects this colonization; moreover, prior antibiotic therapy tends to select out resistant pathogens. Therefore, the selection of empiric antibiotic treatment for this patient is based on the presumption of hospital-acquired bacterial infection in the lung caused by one or more pathogens resistant to first-generation cephalosporins. Cultures of blood and sputum should be obtained; gram stain of the sputum is often helpful in cases such as this, as it may demonstrate a predominate pathogen and whether it is gram-positive or gram-negative. Empiric antibiotic therapy, following ATS/IDSA recommendations for HAP, should be started promptly. A good choice would be an extended-spectrum ß-lactam/ß-lactamase inhibitor or a carbapenem (e.g., piperacillin/tazobactam or imipenem) combined with a fluoroquinolone and vancomycin, pending culture results.

Gram stain of the patient's sputum shows many polys and gram-negative bacilli; the culture is positive for K. pneumoniae and P. aeruginosa. His management, including empiric antibiotic therapy followed by de-escalation (of vancomycin) after culture data are available, conforms to ATS/IDSA recommendations. The patient is treated for 10 days and recovers following a brief period in the ICU.

This case illustrates that the pathogenesis of adult bacterial HAP is essentially the same as for CAP; namely, nasopharyngeal and upper respiratory colonization by virulent bacteria combined with aspiration of infected secretions during a period of impaired host pulmonary defenses. The difference lies in the burden of vulnerability imposed by hospitalization, including the propensity for colonization by gram-negative bacilli and the likelihood of antimicrobial resistance—so uncommon in healthy individuals outside of healthcare facilities, but so prevalent among patients hospitalized longer than 48 hours.