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Porth's Pathophysiology Chapter 3

Terms in this set (17)

Young-old
- Ages: 65-74
Middle-old
- Ages: 75-84
Old-old
- Ages 85+
- Older adults are the largest consumers of healthcare services; most live in community settings
Theories of Aging
- Extrinsic or Stochastic Theories (aka Damage Theories): Aging changes occur 2º accumulation of random events or damage from environmental agents or influences
- Somatic mutation theory: longevity and function of cells are determined by the double-stranded DNA molecules and their specific enzymes ~ aging results from conditions that produce mutations in DNA or deficits in DNA repair mechanisms
- Oxidative free radical theory: aging results partially from oxidative metabolism and the effects of free radical damage
- Wear-and-tear theory: accumulated damage to the vital parts of the cells leads to aging and death
- Intrinsic or Nonstochastic Theories: Aging changes are genetically-programmed
Key changes in musculoskeletal in the older adult
- Progression decline in height
- Body fat increases
- Lean body mass and total body water decrease
- Reduction in muscle size and strength
- Decline in high-speed performance and reaction time
- Bone formation (i.e., renewal) is slower than bone resorption (i.e., breakdown) leading to loss of bone mass and weakened bone structure
- Osteoarthritis is very common (age is greatest risk factor)
Key changes in Integumentary in the older adult
- Skin changes reflect the aging process more obviously than any other organ system
- Skin becomes wrinkled, and dry with uneven pigmentation
- Decreased skin strength and elasticity
- Cellularity and vascularity of the dermis decrease
- Decrease in size, number, and activity of eccrine glands
- Fingernails and toenails become dull, brittle, and thick
- Hair changes
Key changes in Cardiovascular in the older adult
- Cardiovascular disease remains the leading cause of morbidity and death in older adults
- Blood pressure (BP): relationship between BP and risk of cardiovascular disease is continuous, consistent, and independent of other risk factors
- Orthostatic hypotension
- Increase in left ventricular wall thickness, a delay in early left ventricular filling, a decrease in response to beta-adrenergic stimulation and circulating catecholamines, a decrease in the maximal heart rate and maximal cardiac output, and an increase in systemic vascular resistance and left ventricular afterload
- Afterload rises with aging
Key changes in Respiratory in the older adult
- Maximal oxygen consumption, a measure used to determine overall cardiopulmonary function, declines with age but can improve with exercise
- Loss of elastic recoil occurs 2º increase in alveolar diameter which decreases surface tension
Calcification of the soft tissues of the chest wall increased stiffness causes increases the workload of the respiratory muscles
- Increased residual lung volume, increased functional reserve capacity and a decline in vital capacity
Key changes in Neurologic in the older adult
- Weight of the brain decreases with age, and there is a loss of neurons in the brain and spinal cord
- Sensorimotor changes show a decline in motor strength, slowed reaction time, diminished reflexes (noted in the ankles), and proprioception changes leading to potential balance problems and slower, more deliberate movements
- Overall cognitive abilities remain intact
- Changes in personality or significant cognitive deficits warrant evaluation for dementia or depression
Key changes in Special Sensory in the older adult
- Vision: general decline in vision is associated with aging
- Most common disorders is presbyopia, difficulty focusing on a near object, and is caused mainly by decreased elasticity of the lens and atrophy of the ciliary muscle
- Corneal sensitivity may diminish with age
- Hearing: hearing loss is common among older adults, and some degree of impairment is almost inevitable with advancing age: 65-74 year old: 30% experience hearing impairment; older than 75 years of age: 47% experience hearing impairment
- Olfaction, the sense of smell, declines with age
- Sense of taste also diminishes with age
- Polypharmacy (simultaneous use of multiple prescription or over-the-counter drugs) often disturbs the sense of balance in older adults which increases falls
Key changes in Immune in the older adult
- Changes in the function of the helper T cells that alter the cellular immune response in older adults
- Increases in various autoantibodies (e.g., rheumatoid factor) accompanying aging, increase the risk of autoimmune disorders
- Compounding effects of age-related diseases and external conditions overall state of dysfunctional immunity are responsible for the increased risk and severity of common infections in older adults
- Older adults are more susceptible to urinary tract infections, respiratory tract infections, wound infections, and nosocomial infections ~ mortality rate from influenza and bronchopneumonia is increased in this population
- Typical infection symptoms (e.g., fever and elevated WBC) are often absent in older adults making early diagnosis more difficult
Key changes in GI in the older adult
- Shows less age-associated change in function than many other organ systems
- Tooth loss is common ~ approximately 40-50% of the older adult population is edentulous ~ but not considered a part of the normal aging process ~ edentia (toothlessness) can lead to dietary changes and can be associated with malnutrition
- Xerostomia (dry mouth) is common, but is not universal among older adults and typically occurs 2º decrease in salivary secretions
- Atrophy of the gastric mucosa and a decrease in gastric secretions can occur in older adults ~ a decrease in hydrochloric acid secretion can caused impaired gastric absorption of substances requiring an acid environment ~ H. pylori infestation, common in older adults, probably related to gastric atrophy and subsequent decline in gastric acid secretion
- Atrophic gastritis and decreased secretion of intrinsic factor
- calcium absorption decreases with aging
- Diverticula of the colon are common
- Constipation
Key changes in Renal in the older adult
- decreased reserve capacity which may alter the kidney's ability to maintain homeostasis in the face of illness or stressors
- overall decline in kidney mass
- age-related decline in total renal blood flow of approximately 10% per decade after 20 years of age
- Renal tubular function declines with advancing age
- Ability to conserve sodium in response to sodium depletion is impaired
- Decreased ability to concentrate urine, and age-related decrease in responsiveness to antidiuretic hormone
- Impaired thirst mechanism
- more prone to hyperkalemia and hypokalemia when stressed
Key changes in genitourinary in the older adult
- Smooth muscle and supportive elastic tissue in the bladder are replaced with fibrous connective tissue leading to a decline in function
- Bladder capacity diminishes with age; frequency of urination increases
- In women, perineal structures atrophy and may cause the urethral meatus to recede along the vaginal wall ~ diminished estrogen production after menopause leads to atrophy of other pelvic organs ~ vaginal secretions diminish; the vaginal lining is thinner, drier, less elastic, more easily traumatized; normal flora is altered ~ these changes lead to vaginal infections, pruritus, and painful intercourse
- In men, benign prostatic hypertrophy (BPH) is very common ~ the incidence progressively increases with age to approximately 90% of men being affected by 80 years of age ~ BPH can cause obstructive symptoms: urinary hesitancy; diminished force of stream; retention; and post void dribbling ~ may also lead to irritative symptoms: frequency, nocturia, urgency, and even urge incontinence
- Serum testosterone levels decline as men age
Sexual activity remains possible into late life for males and females
Depression
- Most common geriatric psychiatric disorder
- approximately 25% of community-dwelling older adults are thought to have depressive symptoms; 1-2% have major depression ~ depressive symptoms are more common in nursing home residents
- Used to describe a symptom, syndrome, or disease
Dementia
- Syndrome of acquired, persistent impairment in several domains of intellectual function that include memory, language, visuospatial ability, and cognition ~ not a normal component of the aging process
- Prevalence in the US is estimated to be 5-10% with the rate increasing with advancing age
- Up to 70% of demented adults are thought to have Alzheimer's disease: a chronic, progressive neurologic disorder of unknown etiology
- Vascular dementia is second most common dementia disorder
Delirium
- Also known as acute confusional state
- Organic mental syndrome including global cognitive impairment; disturbances of attention; and reduced level of consciousness
- Associated with increased length of hospital stay and poor clinical outcomes
- Up to 70% of cases of delirium are not diagnosed
- Delirium may be seen with disorders such as myocardial infarction; cancer; hypothyroidism; pneumonia and other infections
- Older adults, especially demented older adults, are more likely to become delirious ~ onset of delirium in a demented individual may be mistaken for a dementia exacerbation and go untreated
- Malnutrition, use of physical restraints, and iatrogenic events can precipitate delirium
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