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KEY POINTS

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KEY POINTS

  1. In community-acquired pneumonia (CAP), patients present with cough, fever, dyspnea, or pleuritic chest pain and an infiltrate is seen on chest x-ray; empirical antibiotics include an antipneumococcal beta-lactam and macrolide or respiratory fluoroquinolone for atypical coverage.

  2. Diagnosis of urinary tract infection (UTI) requires symptoms including dysuria, urinary frequency, urgency, suprapubic pain, hematuria, or fever along with a positive urine culture.

  3. Diagnosis and localization of intra-abdominal infection (IAI) can be challenging in the critically ill patient; history, physical examination along with laboratory examination, and imaging are critical.

  4. Necrotizing skin and soft tissue infection is considered a surgical emergency and management includes debridement, resuscitation, and antimicrobial therapy.

  5. Complications of infective endocarditis (IE) are often a reason for admission to the intensive care unit (ICU) and include valvular regurgitation, heart failure, splenic and renal infarcts, mycotic aneurysm, and neurologic complications such as cerebral emboli.

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Community-acquired infections and concomitant sepsis are commonly a reason for admission to the ICU. In these infections, patients typically present with symptoms and signs prior to admission. The most common infections managed in the ICU are described below—CAP, UTIs, IAIs, necrotizing skin and soft tissue infections (NSTIs), and IE.

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COMMUNITY-ACQUIRED PNEUMONIA

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Introduction and Epidemiology

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CAP is one of the most frequent causes of infection-related death in the United States. It occurs in approximately 4 million adults per year, accounting for 1.1 million hospitalizations and 50,000 deaths per year. Of the 20% to 60% of patients who require hospital admission for CAP, anywhere between 10% and 22% may require critical care.1 Mortality rates remain high despite advances in antibiotics and critical care.

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Pathogenesis

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The lower respiratory tract remains sterile because of a combination of pulmonary defense mechanisms that involve anatomic and mechanical barriers, and humoral and cell-mediated immunity. The development of CAP is therefore a result of either a defect in the host pulmonary defense system, an exposure to a virulent or large inoculum of microorganisms, or a combination of these factors.2 Certain risk factors for CAP have previously been described. These include increased age, male sex, malnutrition or poor dental hygiene, high alcohol consumption, smoking, immunosuppression including HIV, asplenia, and other underlying comorbidities.3

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Microbiology

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The most common etiology of CAP remains bacterial or viral; other fungal or parasitic organisms are isolated infrequently and are usually related to various geographic and host factors. Causes of bacterial CAP can be divided into typical or atypical organisms. The most common cause of CAP is Streptococcus pneumoniae; other typical bacterial pathogens include Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and gram-negative organisms such as Klebsiella pneumoniae and Pseudomonas aeruginosa, seen in patients with previous exposure to antimicrobials or structural lung disease. Community-associated methicillin-resistant S aureus (CA-MRSA) as an etiology of CAP should be considered in the appropriate clinical ...

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