Oral Infection and Systemic Disease in the Elderly
Fayaaz Jaffer
Faculty of Dentistry,
University of Toronto.
David W. Matear
Associate Professor,
Director of Clinics,
Faculty of Dentistry,
University of Toronto.
Introduction
The oral health status of older adults is generally poorer than that of the rest of the population. In particular, those residing in institutions have very poor oral health.1,2 The prevalence of systemic infection among the elderly is becoming an increasingly important health care issue, especially since age-related demographics show an increase in the numbers of aging and elderly individuals.
One of the primary portals of entry into the body for infectious agents is the oral cavity, which is home to over 500 bacterial species alone.3 Although most oral microbes are non-pathogenic, decreased host resistance and/or environmental factors, such as institutionalization, can increase the risk of systemic infection among the elderly. Furthermore, once a focal infection has been established, it can open the way to colonization by more virulent organisms. Some of the systemic diseases reported to result from oral infections include pneumonia, meningitis, osteomyelitis, bacterial endocarditis, as well as abcesses of the brain, lung, and liver. This article will provide examples of the impact of oral diseases on general health in the elderly.
Aspiration Pneumonia
Both bacteria and viruses can cause pneumonia, a disease that can be particularly dangerous in the elderly since they are commonly immunosuppressed. Aspiration of oropharyngeal microbes into the lower respiratory tract is a common route for infection.1,4,5 Bacterial pneumonia is mainly associated with anaerobic or mixed anaerobic/aerobic infections. Age (>70 years), history of smoking, immuno-suppression, and previous antibiotic treatment are some of the risk factors that may predispose non-institutionalized individuals to community-acquired pneumonia.1,2,4 Nosocomial pneumonia has additional risk factors, including the need for mechanical ventilation, hospitalization in the fall or winter seasons, prolonged pre-operative stays, and/or prolonged surgery.2,4
Poor oral hygiene among the elderly has been found to be associated with dental plaque containing high numbers of potential respiratory pathogens, such as Streptococcus pneumoniae, Staphylococcus pyogenes, Mycoplasma pneumoniae and Haemophilus influenzae.4 The oral cavity has been hypothesized to act as a reservoir for these organisms prior to aspiration into the lungs. Many case reports have also demonstrated a possible role of oral microbes in aspiration pneumonia and lung abscesses. While Actinobacillus actinomycetemcomitans, Actinomyces israelii, and Prevotella intermedia are some of the oral microbes implicated in these cases, a few studies have shown other common subgingival anaerobes including Porphyromonas gingivalis and Fusobacterium species to be also associated with pneumonia.4,6 It is important to note that the literature supports a positive association between poor oral hygiene or periodontal disease and pneumonia. Proper management of poor oral hygiene and periodontal disease in the elderly may be of great importance in terms of decreasing the likelihood of pneumonia and its consequences, which also include high health care costs associated with medical treatment of pneumonia.
Infective Endocarditis
Infective endocarditis (IE) is a disease caused by a microbial infection of the heart valves or endocardium, and is often associated with congenital or acquired cardiac defects.7 The mean age of onset for IE is 60 years.8 Some authors believe the incidence of IE has increased since the 1940s, despite the advances made in the field of antibiotics.8 This may be attributable to an increase in cardiac valvular disease, immunosuppression, as well as to the fact that nowadays more individuals remain dentate and hence are at a higher risk of developing oral disease. Aortic stenosis, prosthetic heart valves, mitral valve prolapse causing regurgitation, surgically constructed systemic/pulmonary shunts and rheumatic valvular disease are some of the cardiac conditions that increase the susceptibility of elderly patients to IE; this is particularly relevant for those