Physiology-Geriatrics Flashcards
Most rapidly growing segment of society
80-85. For the 1st time in history the elderly outnumber kids
How does health relate to age as patients get older and older?
Health becomes more and more heterogeneous. Note that you can’t relate medical disability to ability to function independently
Compression of Morbidity Hypothesis
By postponing development and age-related diseases, disability can be compressed into the last few years of life and life expectancy is typically fixed.
What is a common factor seen in many centenarians?
They maintain cognitive function well into their 9th decade and maintain independent functionality.
3 paths to extreme longevity (centenarian)
1) Survivor (43%): avoids disability despite developing common age-associated disease 2) Delayers (42%): develop age-associated diseases much later 3) Escapers (15%): avoid age-associated diseases until the final stages of life (fulfilling the compression of morbidity hypothesis)
Why some elderly patients won’t receive a knee replacement
Dissuaded by surgeon because of long list of comorbidities, even though they can live a long time despite the comorbidities
What contributes to development of disease as people age?
Genetic, lifestyle and environmental factors account for disease, typically it is not the normal aging process
Cardiac changes with aging
Diminished early diastolic filling (more prone to CHF from loss of atrial kick), increased pulse wave velocity (stiffening of blood vessels), myocardial hypertrophy, decreased compliance of blood vessels (increased pulse pressure = S4), ischemia from low diastolic pressure.
Renal changes with aging
Renal atrophy (loss of mass & glomeruli), diminished GFR, increased post-void residual urine and decreased renal blood flow.
Pulmonary changes with aging
Diminished ciliary clearance (increased infections), decreased respiratory muscle strength, impaired cough reflexed, diminished respiratory response to hypoxemia and hypercapnea
CNS changes with aging
Changes in psychomotor speed, memory, cerebral atrophy (could be normal), diminished PNS conduction velocity, decreased fine motor control
MSK changes with aging
Loss of muscle mass, OA, degenerative changes in bones and discs, decreased metabolic rate (increased fat: muscle)
Neurologic changes with aging
Limited up gaze, slow saccades, diminished Achilles reflex, stooped posture and Parkinsonian findings.
Integument changes with aging
Senile purpura, xerosis, benign skin lesions (cherry angiomata, seborrheic keratosis, actinic keratosis)
Gradual compression of reserve in various physiologic systems
Homeostenosis: increasing susceptibility to disease due to stressors, diminished reserve and increased weakness. This is very important to consider when working up a patient or giving an elderly patient medications with side effects that may cause stress to these weakened systems.
Weakest links in the elderly physiologic system?
Brain (delirium), GU (incontinence) and MSK (falls, poor mobility). This is thought because these systems rely on widely distributed neurologic networks.
What is a critical concept to remember when an elderly patient is being worked up?
Sometimes evaluations of the “weak links” (brain, GU, MSK) can be detrimental to the patients health and the work up should be limited to the most pertinent presentation (pneumonia instead of dementia). Contrast this to evaluating a younger person with CNS abnormalities where you would always do a full work up
Concurrent presence of 2+ medically diagnosed diseases in the same individual
Comorbidity (2/3 of people 65+ have 2+ chronic conditions)
Difficulty or dependency carrying out activities essential to independent living and desired activities
Disability
A state of increased vulnerability to poor resolution of homeostasis after a stressor (poor physiologic reserve). Characterized by low muscle mass, weight loss, weakness, fatigue, exhaustion, poor gait speed, balance deficits and cognitive impairment.
Frailty.
Acute alteration of consciousness and cognitive function characterized by inattention, disturbed psychomotor activity, perceptual disturbances and altered circadian rhythm? How common is this?
Delirium, affects 1/3-1/2 of hospitalized elderly patients, but 70% of cases go undetected. Often a sign of potentially life-threatening illness (pneumonia, abdominal infection etc)
An acquired syndrome of cognitive decline typically involving memory and at least one other cognitive domain of sufficient severity to impair everyday function? How common is this?
Dementia, affects 1/3 of people by age 80. Often not diagnosed until later stages because patient/family members see cognitive decline as a normal process of aging.
What things might also improve if a patient improved from delirium/dementia?
Mobility (more steady and less falling) and GU (diminished incontinence). These are the “weak links”. Conversely, these abilities will decline together.
Why might medical decisions be difficult for a physician treating the oldest of the old?
There is very little evidence based medicine in this population. This is because these patients often have comorbidities that exclude them from clinical trials. Polypharmacy, shifting priorities and clinical guidelines also make treatment difficult.
