Periodontal Disease And Acute Respiratory Infections

The upper respiratory passages are often contaminated with organisms derived from the oral, nasal, and pharyngeal regions. Conversely, the lower airways in which gas exchange occurs are generally maintained free of microorganisms by a combination of host immune factors and mechanical clearance through the cough reflex, ciliary transport of aspirated contaminants, and movement of secretions from the lower airways into the trachea.4" Pneumonia is an infection of the lungs caused by bacteria, viruses, fungi, or mycoplasma and is broadly categorized as either community-acquired or hospital-acquired. A wide variety of bacteria may cause pneumonia, and the spectrum of offending organisms differs markedly between community-acquired and hospital-acquired infections.

(lonimiiiiity-acqiiirccl bacterial pneumonia is caused primarily by inhalation of infectious aerosols or by aspiration of oropharyngeal organisms. .V. pneumoniae and Haemophilus influenzae are most common, although numerous other species may occ ur, including anaerobic bacteria.""' \ntibiotic therapy is highly successful in resolution of most cases of communitv-acqiiired bacterial pneumonia. To date, no associations have been found between oral hygiene or periodontal disease and the risk tor acute respiratory conditions such as pneumonia in community-dwelling individuals.'1

The same cannot be said tor individuals in the hospital setting. Hospital-acquired (nosocomial) I meter ial pneumonia has a very high morbidity and mortality rate. Approximately 20% to S0% of patients with nosocomial pneumonia die." The incidence of nosocomial pneumonia is highest in severely ill patients such as those in intensive care units or on ventilatory support. More than half of patients on mechanical ventilation tor several days or more acquire pneumonia. Although nosocomial pneumonia is most commonly caused by gram-negative aerobic organisms, many cases are the result of infection by anaerobic bacteria, including those commonly found in the subgingival environment.

Hospital-acquired pneumonia is usually caused by aspiration of oropharyngeal contents. Oropharyngeal colonization with potential respiratory pathogens (PRPs) increases during hospitalization, and the longer the hospital stay the greater the prevalence ol PRPs."' PRPs arc-found predominantly in the gastrointestinal tract and may be passed through esophageal reflux into the oropharynx where they colonize. Subsequent aspiration may lead to pneumonia. Patients whose posterior oropharynx becomes colonized with PRPs have a significantly increased risk of developing nosocomial pneumonia compared with those without oropharyngeal colonization by PRPs.

Selective decontamination is a technique that combines systemic antibiotics with oralis administered nonabsorbable antibiotics in an attempt to eradicate PRPs from the digestive tract and oropharynx and to thereby minimize the risk of nosocomial respiratory infections. The technique is used primarily in patients who are intubated and on mechanical ventilators. Selective de-con lamination significantly decreases the incidence ot nosocomial pneumonia." Decontamination of only the digestive tract does not reduce the incidence ot pneumonia, but decontamination ol the oropharynx alone does."""8 This provides further evidence that the oropharynx is the primary site ot PKP colonization, with subsequent aspiration of causative organisms leading to pneumonia.

PRPs may also originate in the oral ca\ it\. with dental plaque serving as a reservoir of these organisms. Poor oral hygiene is common in the hospital and nursing home settings, especially in severely ill patients." PRPs are more commonly isolated from supragingival plaque and buccal mucosa of patients in intensive care units than in outpatient settings."1 Thus organisms that are not routinely found in dental plaque become plaque colonizers after prolonged hospitalization. Subgingival plaque may also harbor PRPs, and putative periodontal pathogens have been associated with nosocomial pneumonia. Furthermore, anaerobic organisms from periodontal pockets may serve as the primary inoculum for suppurative respiratory diseases such as pulmonary abscesses that have significant morbidity and mortality.*1 Although considerable circumstantial evidence suggests I hat periodontal pathogens may cause acute nosocomial pulmonary infections, currently no published studies specifically demonstrate an increased risk of such infections in patients with periodontal disease. Likewise, there is no research evaluating the effects of periodontal treatment on the incidence of bacterial pneumonia.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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