Older People - Patterns of Illness, Physiological Changes and Multiple Pathology
Physiological changes occur with ageing in all organ systems.
- The cardiac output decreases, blood pressure increases and arteriosclerosis develops.
- The lungs show impaired gas exchange, a decrease in vital capacity and slower expiratory flow rates.
- The creatinine clearance decreases with age although the serum creatinine level remains relatively constant due to a proportionate age-related decrease in creatinine production.
- Functional changes, largely related to altered motility patterns, occur in the gastrointestinal system with senescence, and atrophic gastritis and altered hepatic drug metabolism are common in the elderly.
- Progressive elevation of blood glucose occurs with age on a multifactorial basis and osteoporosis is frequently seen due to a linear decline in bone mass after the fourth decade.
- The epidermis of the skin atrophies with age and due to changes in collagen and elastin the skin loses its tone and elasticity.
- Lean body mass declines with age and this is primarily due to loss and atrophy of muscle cells (sarcopenia)
- Degenerative changes occur in many joints and this, combined with the loss of muscle mass, inhibits elderly patients' locomotion.
These changes with age have important practical implications for the clinical management of elderly patients: metabolism is altered, changes in response to commonly used drugs make different drug dosages necessary and there is need for rational preventive programs of diet and exercise in an effort to delay or reverse some of these changes.
Morbidity and Ageing
Distinguishing the accumulation of age related disease (morbidity) from true ageing is difficult.
- Gradual onset of alterations in voice, in facial appearance, cold sensitivity, lethargy and slowing may be easily attributable to the ageing process that myxoedema (decreased activity of the thyroid gland) can be overlooked.
- Postural changes, stiffness and restricted activity often considered a part of ageing may cause the rigidity and bradykinesia of Parkinson’s to be missed.
Investigations are often provoked due to comments from a visitor, especially one who has not seen the person for a long time and to whom the changes are noticeable.
Physiological Changes in Older Adults
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Body composition changes in old age
- The human body is made up of fat, lean tissue (muscles and organs), bones and water. After the age of 40, people start losing their lean tissue. Body organs like liver, kidneys and other organs start losing some of their cells. This decline in muscle mass is associated with weakness, disability and morbidity
- Height loss is associated with ageing changes in the bones, muscles and joints. People typically lose about 1 cm every 10 years after age 40. Height loss is even more rapid after age 70. These changes can be prevented by following a healthy diet, staying physically active and preventing and treating bone loss.
- Changes in the total body weight vary for men and woman, as men often gain weight until about age 55 and then begin to lose weight later in life. This may be related to a drop in the male sex hormone testosterone. Women usually gain weight until age 67–69 and then begin to lose weight. Studies have also shown that older people may have almost one-third more fat compared to when they were younger. Fat tissue builds up towards the centre of the body, including around the internal organs
- The vestibular system entails vestibular nerve, brainstem and cerebellar processing circuits and this system in germane in postural balance, self motion and spatial orientation.
- Ageing physiological changes in the vestibular system may lead to a greater falls risk.
- Physiological change in the vestibular system of older adults may explain dizziness and imbalance, benign positional paroxysmal vertigo among older adults.
Altered Responses to Illness
- Illnesses often present differently in old age than in youth.
- Regulation of body temperature is unstable or less responsive, so pyrexia may not be as marked as would be expected even in severe infections such as pneumonia, appendicitis or pyelonephritis.
- A lack of awareness of cold, or of the capacity to react normally to it, may lead to hypothermia
- Delirium precipitating factors including immobility, malnutrition, inter-current illness, dehydration and, stress of admission to hospital or other unfamiliar settings.
- Pain is common in older people. However as people age, they complain less of pain. The reason may be a decrease in the body's sensitivity to pain or a more stoical attitude toward pain.
- Some older people mistakenly think that pain is an unavoidable part of ageing and thus minimize it or do not report it.
- In conditions that cause intense pain in earlier life (e.g. angina or fractures), there may be so little discomfort, or pain is referred in such a bizarre way, that diagnosis is delayed – sometimes with fatal consequences.
- Pain is often not correctly recognized and treated in people with dementia, and use of a scale such as the Abbey pain scale may help to recognize when a person is in pain.
Response to Drugs
- Poly-pharmacy is a common phenomenon among the older adults and this is because ageing is a risk factor for many chronic conditions.
- Physiological changes in older adults and polypharmacy contribute to adverse drug reactions seen in older adults.. It has been claimed that the adverse drug reaction in older adults is due to increased pharmacodynamic sensitivity and a prescription error.
- When prescribing drugs to older adults, their physiological responses to these drugs need to be considered.
Recovery from Illness
- Due to physiological changes seen in older adults as a result of aging, recovery becomes slowed once they become ill.
- Older adults rarely recover to their baseline in functional activities of daily living after acute medical illness.
- There seems to be association between heart rate recovery and performance.
- Aging effects on both the cardiovascular system and cognitive performance may explain some of the reasons why older adults may be slowed to recover from illness.
- In recent years with a rising percentage of elderly population, epidemiologists, researchers, demographers and clinicians have focussed their attention towards elderly care health issues and various problems associated with ageing and numerous implications of this demographic transition.
- Elderly face various problems and require a multi-sectoral approach involving inputs from various disciplines of health, psychology, nutrition, sociology and social sciences.
- See also Perceptions about Ageing and Ageism
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- Boss GR, Seegmiller JE. Age-related physiological changes and their clinical significance. Western Journal of Medicine. 1981 Dec;135(6):434.Available from: https://pubmed.ncbi.nlm.nih.gov/7336713/(accessed 10.4.2021)
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- Elie M, Cole MG, Primeau FJ, Bellavance F (1998). Delirium Risk Factors in Elderly Hospitalized Patients. J Gen Intern Med; 13(3): 204–212
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- Keary TA, Galioto R, Hughes J, Waechter D, Spitznagel MB, Rosneck J, Josephson R, Gunstad J. Reduced heart rate recovery is associated with poorer cognitive function in older adults with cardiovascular disease. Cardiovascular psychiatry and neurology. 2012;2012.
- Boyd CM, Landefeld CS, Counsell SR, Palmer RM, Fortinsky RH, Kresevic D, Burant C, Covinsky KE. Recovery of activities of daily living in older adults after hospitalization for acute medical illness. Journal of the American Geriatrics Society. 2008 Dec;56(12):2171-9.