Aging & the Immune System

Draft 7-21-05 Aging & the Immune System Content for this module provided by The John A. Hartford Foundation, Institute for Geriatric Nursing, Online Gerontological Nursing Certification Review Course http://www.nyu.edu/education/nursing/hartford.institute/course/ Support for this project provided to School of Nursing, University of Washington by the John A. Hartford Foundation, Geriatric Nursing Education Grant and Nursing School Geriatric Investment Program Grant. Draft 7-21-05 Aging & the Immune System • Age-related changes to immune system • Other factors affecting immunocompetence • Age-related physiological changes • Nutrition • Psychosocial • Lifestyle • Drugs Draft 7-21-05 Aging & the Immune System •  immunocompetence,  stress response •  inflammatory response – Infection in older adults is more difficult to detect – Slight & subtle symptoms should be taken seriously! – Older adults often have serious infection without a fever! Draft 7-21-05 Aging & the Immune System Overall  ability to provide protection: •  infections •  cancer •  autoimmune process •  chance for associated illnesses •  risk of death Draft 7-21-05 Normal Immune System Changes •  effectiveness of physical barriers •  cellular (T-cell mediated) immunity •  humoral (B-cell mediated) immunity Draft 7-21-05 Normal Immune System Changes  effectiveness of physical barriers • Changes in skin and mucous membrane • skin becomes more fragile & prone to breakdown or abrasion •  amount of available immunoglobulin A (IgA) to protect against infection Draft 7-21-05 Normal Immune System Changes  cellular (T-cell mediated) immunity – Atrophy of thymus –  function and production of T-lymphocytes –  T-cell proliferation when exposed to antigens –  proliferation of natural killer cells –  production of cytokines needed for growth & maturation of B cells – Memory from previous exposures is maintained, but there is  response to new antigens Draft 7-21-05 Normal Immune System Changes  humoral (B-cell mediated) immunity •  production of immunoglobulins by B lymphocytes •  production of auto-antibodies •  primary response, secondary response is maintained Draft 7-21-05 Normal Immune System Changes  humoral (B-cell mediated) immunity (cont’d) • Impaired ability to resist infection •  risk of reactivation of latent infection (such as TB) • Inhibited antibody response to foreign antigens (such as a negative response to a PPD skin test when actually positive) •  hypersensitivity or allergic reactions Draft 7-21-05 Normal Physiological Changes & Immunity • Impaired skin integrity –  risk of bacterial or fungal infections • Weakening of respiratory muscles,  chest expansion,  residual volume –  susceptibility to pneumonia,  ability to resolve • Weak bladder muscles & residual urine –  risk of UTIs, especially if: • other chronic illness is present, pt is immobile, pt has a foley catheter Draft 7-21-05 Nutrition & Immunity Nutritional deficiencies • 1/3 adults > age 65 • Contributing factors: • • • • • altered taste social isolation physical inability to prepare food altered absorption poverty • Immunity • reductions in delayed cutaneous hypersensitivity •  # &  responsiveness of T- cells Draft 7-21-05 Nutrition & Immunity Nutritional deficits:  potential for impaired healing & diminished immune response • Insufficient protein & energy (calories) intake • Iron & trace mineral deficiencies (zinc, selenium, copper) • Vitamin deficiencies (A, C, D, E & B6) • Fat intake • unsaturated (esp. excessive) & polyunsaturated (saturated fats are associated w/  T-cell responsiveness) Draft 7-21-05 Other Factors & Immunity • Psychosocial* • chronic & acute stress, depression, bereavement, social relationships • Lifestyle • activity level, smoking • Drugs • immunosuppressants, immunoenhancers, corticosteroids, cyclosporin, chemotherapeutics • alcohol, marijuana *emerging awareness - clinical relevance remains a source of investigation Draft 7-21-05 Infection Assessment Atypical signs & symptoms •  in mental status • decline in functional status • weight loss •  in appetite • afebrile Do not dismiss as normal age-related changes!*** ***All slight & subtle symptoms s/b taken seriously Draft 7-21-05 Pneumonia Atypical presentation • Delayed fever, low grade fever, or temperature +/2 degrees from baseline • No signs of consolidation (~30% of elderly), including crackles, wheezing, pleuritic chest pain, bronchial breath sounds • Subtle signs of anorexia,  in mental status & activity levels, weight loss, & failure to thrive Draft 7-21-05 Tuberculosis Typical presentation in younger persons Fever, chills, night sweats, hemoptysis, weight loss • Atypical presentation in older persons • Cough, weight loss, complaints of weakness • Sx are often vague and mirror those of other chronic conditions Draft 7-21-05 Urinary Tract Infection Symptomatic presentation (less common) – Dysuria, frequency, urgency Asymptomatic presentation – New onset incontinence (particularly in females) – Mental status  , incld’g confusion, disorientation – Lethargy, nausea, vomiting, & abdominal pain – Delayed/low grade fever, or temp +/- 2 degrees from baseline Draft 7-21-05 AIDS • Progression is faster in older adults • Survival time is reduced • Less physiological tolerance of treatment •  influenza, bacterial pneumonia, TB (watch for false negative PPD) • AIDS related dementia Draft 7-21-05 Nursing Interventions & Risk of Infection • Preventative measures & early detection • Nutrition & hydration – ongoing assessment & intervention • dry thinning hair, wasting of muscle mass, moisture of lips & mouth (weekly weights for high risk deficits) • Recognize slight differences in behavior & function • Safe environment