physiology of aging 2005
TRANSCRIPT
Learning ObjectivesLearning Objectives
By the end of this section, the student will appreciate the importance of – physiological and psychological factors that
contribute to normal aging, – the difference between normal aging and the
diseases of aging.– frailty and co-morbidity in the presentation of
disease in the elderly
Normal AgingNormal Aging
Despite stereotype most of the elderly age well!
Normal AgingNormal Aging
Despite stereotype most of the elderly age well! Most of our images are based on the frail sub-set
who frequently use medical services
Normal AgingNormal Aging Despite stereotype most of the elderly age well! Most of our images are based on the frail sub-set who frequently use medical
services Generally normal aging is associated with a reduction in functional reserve
capacity in tissues and organs
Age related change in function Age related change in function reservesreserves
Normal AgingNormal Aging Despite stereotype most of the elderly age well! Most of our images are based on the frail sub-set who frequently use medical services Generally normal aging in associated with a reduction in functional reserve capacity in tissues and
organs At advanced age more common to see evidence of impaired homeostasis and response to external
insults (e.g. illness)
Traditional medical approaches do not cater for the heterogeneity of disease in
the elderly!
Skin and AgingSkin and Aging
In general, the skin tends to become drier, thinner, and more wrinkled with age. Other age-related changes include:– Loss of the inter-digitations between the epidermis and
dermis, leading to ease of tearing or breakdown (see picture opposite).
– Decline in the vascular supply which influences thermoregulation as well as drug absorption and the response to toxic substances.
– Decline in the immune cells of the integument. – Decline in the activation of Vitamin D.
Skin and AgingSkin and Aging
Consequences of Aging SkinConsequences of Aging Skin
Older skin tends to be more vulnerable to tearing, bruising, and breakdown.
Pressure ulcers (decubiti), are seen more commonly within the hospitalized elderly.
There may be delayed response to topically-administered toxic agents.
Exposure to sunlight exacerbates age-related changes in the skin.
Cardiac Output and AgeCardiac Output and Age
Heart Rate and AgeHeart Rate and Age
CardiovascularCardiovascular
Higher Syst. BP more common
Reduced ability to increase HR
Increased postural hypotension
Prone to diastolic dysfunction
RespiratoryRespiratory
Increased energy of breathing Increased airways resistanceIncreased in dead-spaceReduced V/Q ratio
Sensory (1)Sensory (1)
Vision– The lens tends to opacify, which
influences color perception. – There is a decrease in light and dark
adaptation. – The lens tends to lose elasticity,
which increases the distance of focusing.
– There is a decline in contrast sensitivity and an increase in sensitivity to glare.
Sensory (2)Sensory (2)
Hearing– Hair cells tend to be lost in the organ
of Corti. – Cochlear neurons tend to be lost. – Stiffening, thickening, and
calcification occur in multiple components of the auditory apparatus.
Taste– Older persons may have decreased
sensitivity to taste.
NeuromuscularNeuromuscular Reduced sensory input including propio-ceptive
information Delayed nerve conduction Reduced numbers of motor neurones Reduced fast twitch fibres Reduced muscle mass
Therefore vulnerability to falls!
Osteoporosis and FracturesOsteoporosis and Fractures Low dietary intake of Calcium Loss of endocrine protection Reduced endogenous production of Vitamin D Disuse Disease – Chronic Renal Disease, Rheumatoid
Arthritis, Thyroid Disease Medications – Steroids, Thyroxine
Sobering Facts re Falls in ElderlySobering Facts re Falls in Elderly
4,821 per 100,000 pop. over 65 attend A&E with falls and almost 25% resulted in hospitalization
90% of “faller”s sent home from A&E have no change in fall-risk factors
40% of Fallers presenting to A&E will # within one year
Life time risk for hip # in males 11% and females 27%
Estimated in 2001 one year cost of hip # was $26,527 ($21,365 in those -> community and $44,156 -> LTC)
Sobering Facts (2)Sobering Facts (2)
Less than 40% of # hip patients will regain previous level of ambulation!
7% short-term mortality rising to 20-35% after one year!
Restraints increase incidence of serious falls40% of admissions to LTC are “frequent
fallers”Fall rate increases in first six weeks in LTC!
The Digestive SystemThe Digestive System
• Stomach motilitypH
• Sm. Intestineabsorption
• Large Intestinemotility
• Liver•blood flow
RenalRenal
General decline in glomerular filtration rate by about 8-10ml/min per 1.73m2 per decade after age 30-35.
Progressive decline in ability to excrete a concentrated or a dilute urine
Delayed or slowed response to sodium deprivation or a sodium load
Delayed or sluggish response to an acid load
Pharmacokinetics and AgingPharmacokinetics and Aging Absorption - gastric pH higher, decreased motility
and absorption Distribution - reduced total body water, proteins and
lean body mass, and increased total body fat Metabolism - hepatic oxidative pathways impaired
(benzodiazepines) and P-450 (B-blockers, TCA’s, verapamil)
Excretion - reduced GFR and change in tubular function (aminoglycosides, lithium, digoxin)
Low Body Water -> reduced vol. of dist. for polar drugs eg. Aminoglycocides, Digoxin
High Fat Stores -> increased vol. of dist. for lipid soluble drugs eg. Phenytoin, Diazepam, Flurazepam
Pharmacokinetics and AgingPharmacokinetics and Aging Absorption - gastric pH higher, decreased motility
and absorption Distribution - reduced total body water, proteins and
lean body mass, and increased total body fat Metabolism - hepatic oxidative pathways
(benzodiazepines and P-450 (B-blockers, TCA’s, verapamil)
Excretion - reduced GFR and change in tubular function (aminoglycosides, lithium, digoxin)
PharmacodynamicsPharmacodynamics((effect of drugs at target siteeffect of drugs at target site))
No generalization regarding receptor numbers or affinity or hormone levels
Examples of changes are insulin receptors, Beta receptors and heart, Ach receptors and colon
Genitourinary (men)Genitourinary (men)
Decreased blood flow may lead to a decrease in erectile function.
Spermatogenesis continues, although sperm count tends to decline and chromosomal abnormalities tend to increase.
The prostate tends to increase in size, and prostatic fluid tends to decrease in amount.
Genitourinary (women)Genitourinary (women)
Reproductive capacity is lost at the time of menopause.
Ovary, uterus, and vagina tend to atrophy following menopause
The urethra is more likely to be colonized by gram negative organisms.
Alterations in mucosa lead to increased bacterial adherence.
Newer results...Newer results...
The Starr-Weiner report: – 97% liked sex– 91% approved of unmarried/widowed aged
having sex– quality more important than frequency!– Women in survey had intercourse 1.4/week
Newer results...Newer results...
Large proportion of seniors sexually active:– 54% of married men & women– 65% of women over age 70
Netherlands: 34 % of women surveyed enjoy sexual activity most of time– Vs. 70% of premenopausal women
What problems may women What problems may women reportreport
43% of older Swedes reported vaginal dryness
10% vaginal burningurinary incontinence may occurdyspareuniadecreased orgasm (30%)
What changes for men?What changes for men?
Changed libidoerectile function
– increased need for stimulation– inadequate rigidity associated with risk factors
decreased ejaculatory demanddecreased ejaculatory powerprolonged refractory stage (up to one week)
Impact of Physiological and Impact of Physiological and Epidemiological Factors in the Epidemiological Factors in the Elderly and the Health Care Elderly and the Health Care
SystemSystem
John Puxty, Queen’s University
Atypical presentations of disease Atypical presentations of disease are frequently seen are frequently seen
Classical Silent Pseudosilent Atypical Presentations
Weakness/FatigueDwindles Falls/Immobility
IncontinenceCognition/Mood ChangeSocial Crisis
High users have overlap of High users have overlap of physical and social vulnerabilitiesphysical and social vulnerabilities
Predictors of FrailtyPredictors of Frailty
Extreme ageVisual lossImpaired cognition/moodLimb weaknessAbnormalities of gait and balanceSedative useMultiple chronic diseases
Acute illness superimposed Acute illness superimposed on Frailtyon Frailty
Multiple organ stress Failure of homeostasispotential exacerbation of chronic diseasesIncreased potential for drug interactions and
adverse effectIncreased vulnerability to delirium, falls and
incontinence with caregiver stress
Significance of the Significance of the “Atypical Presentation” “Atypical Presentation”
Presence associated with delay in diagnosis and increased mortality (Puxty et al 1984)
Predictive of future functional declines in community elderly (Choo-Cho et al 1998)
Functional decline (dwindles) increases likelihood of further decline and increased mortality (Hebert et al1997)
Clinician’s general approach Clinician’s general approach to the “Atypical Presentation”to the “Atypical Presentation”
Consider recent change in function a result of disease or drugs until proven otherwise
Longitudinal multiple assessments often necessary
Additional informants often invaluableAppropriate screening investigations have a
roleMultiple pathologies are the rule
Small changes can result in major functional gains!
MedicationsFoot wearWalking aidesSurface heightsChairs/bedWall barsLightingFlooring/mats
ConclusionsConclusions Aging of the population will result in 25% of the
population being over 65 by 2030 The majority of the elderly are well and enjoy a
reasonable socio-economic status A small but significant subset of frail, vulnerable elderly
account for an excess of adverse socio-economic and health care outcomes
A typical profile is the very old, female, living alone, with multiple chronic diseases and taking multiple medications
The presence of acute illness should be suspected with recent unexpected functional decline