2. Aim of the review
• An improved understanding of the age-
associated changes in pulmonary host
defense mechanisms and how these might be
manipulated to reduce the susceptibility of
the elderly to respiratory tract infections may
reduce the possibility of severe debilitation
and death and the considerable health care
burden posed by the increased incidence of
pneumonia in this at-risk population.
3. Causes of pnemonia in elderly people:
AGE-ASSOCIATED CHANGES IN LUNG
STRUCTURE AND FUNCTION.
ADVANCING AGE, IMMUNITY AND
PULMONARY HOST DEFENSE MECHANISMS
CHANGE.
4. AGE-ASSOCIATED CHANGES IN LUNG
STRUCTURE AND FUNCTION.
Structural and anatomic changes in the lungs
• Disruption and loss of elastin fibers
• Altered cross-linking of matrix (elastin and
collagen)
• Decrease in diameter of small bronchioles
• Enlargement of terminal airspaces
• Increased number of pores of Kohn(discrete holes in
walls of adjacent alveoli).
• Loss of total alveolar surface area
• Decrease in number of capillaries per alveolus
5.
6. Other respiratory system changes
• Decrease in mucociliary clearance efficiency
• Decrease in respiratory muscle function
• Decrease in chest wall compliance plus altered chest
wall contour.
Changes in lung physiology and function
• Decrease in lung elastic recoil (increased lung
compliance)
• Increase in residual volume and FRC
• Decrease in FVC and forced expiratory flows (FEV1,
FEF25–75)
• Decrease in inspiratory capacity
• Decrease in DLCO
• Decrease in PaO2
• Decrease in maximal oxygen consumption with exercise
7.
8. • FVC: Forced vital capacity: Max. amount of air you
can inhale and exhale .
• FEV: Forced expiratory volum: Max. amount of air
you can exhale in one second .
• FEF: Forced expiratory flow: speed of air coming
out of lung generally, defined by what fraction remains of
the forced vital capacity (FVC).
• FIF: Forced inspiratory flow: speed of air coming
into lung.
• Dlco: Diffusing capacity: is the carbon monoxide
uptake from a single inspiration in a standard time
(usually 10 seconds).
• PaO2 :Partial pressure of oxygen in arterial blood .
9. ALTRATION IN IMMUNITY AND PULMONARY
HOST DEFENSE MECHANISMS
Adaptive (antigen-specific) immunity
Cell-mediated immunity:
• Thymus involution (thymus gland begins gradually to
involute shortly after birth and undergoes replacement by
fatty tissue that is nearly complete by the age of 60 yr).
• Decrease in naive T-lymphocyte production
• Altered memory T-cell function
• Increase in peripheral memory T lymphocytes
• Decrease in proliferative responses to antigens and mitogens
• Th1 to Th2 cytokine shift
• Increase in HLA-DR expression
• Decrease in diversity of T-lymphocyte receptor repertoire
• Decrease in Fas-mediated T-cell apoptosis
10. Humoral immunity
• Decrease in B cell number
• Decrease in germinal center formation
• Altered antibody responses to specific antigens
– Decrease in B-lymphocyte receptor repertoire
– Dysfunctional generation of primary B lymphocytes
– Impaired production of memory B cells
– Decrease in generation of protective antibodies with
high affinity for antigen
• Increase in IgA and IgG
• Increase in auto antibodies
11. Innate immunity
• Decrease in natural killer activity in
association with impending morbidity
• Decrease in γδ T cell proliferation and number
• Decrease in efficiency of antigen presentation
by dendritic cells
• Deregulated cytokine production
• Decrease in macrophage and neutrophil
function
12. CHANGES IN BAL IMMUNE PARAMETERS
ASSOCIATED WITH ADVANCED AGE
Adaptive immunity
• Increase in CD4/CD8 T-lymphocyte ratio
• Increase in total lymphocytes
• Increase in HLA-DR T cells
• Decrease in B lymphocytes
• Increase in IgM, IgA, and IgG concentrations
Innate immunity
• Increase in neutrophils
• Increase in IL-6 and IL-8
• Increase in superoxide anion production by alveolar macrophages
Other changes
• Increase in total protein and α1-antitrypsin
• Decrease in vascular endothelial growth factor
13. RISK FACTORS FOR BACTERIAL
PNEUMONIA IN THE ELDERLY
Dysfunctional immune defense mechanisms
• Immune suppression
• Drugs (e.g., corticosteroids)
• Systemic disease (e.g., malignancy, renal failure)
• Age-associated decline
Predisposition to aspiration of upper airway or
oral secretions
• Central nervous system dysfunction
• Swallowing disorders
• Sedating medications
14. Depressed clearance mechanisms
• Mechanical reflexes (cough)
• Oral clearance (salivary flow)
• Mucociliary clearance
Admission to a medical care facility
• Recent hospitalization
• Long-term care facility
Organ system dysfunction
• Parenchymal lung disease
• Other (cardiac, renal, hepatic)
• Chronic disease (diabetes, rheumatologic)
16. PREVENTION AND TREATMENT OF
PNEUMONIA IN THE ELDERLY
• Rapid diagnosis.
• Prompt administration of empiric antibiotic therapy.
• The pneumococcal and influenza vaccines andrevaccination
5 years after the first dose has been advocated .
• Smoking cessation
• Minimizing the risk of aspiration
• Optimizing nutrition
• Avoiding institutionalization
• Giving neuraminidase inhibitors for early treatment of viral
influenza or for prophylaxis.
