Musculoskeletal

Ability to perform daily tasks independently decreases with age even in healthy elderly adults and is greatly affected by changes in the musculoskeletal system. Such changes can lead to further disuse and injuries resulting in significant pain and disability. The musculoskeletal system is responsible for limb movement, and it provides structural support for the body and protection for soft tissue. Muscle and bone physiology is a metabolically and functionally integrated system affected by other systems (e.g., the endocrine system). The use of a systems biology approach can be valuable in that it permits the consideration of how these components interact.

Neurologic

Increasing age is associated with decreased brain volume, frontal gray matter loss, and decreased cerebral blood flow. Cortical thinning occurs along with a shifting of brain activity from the posterior to the anterior regions. Cognitive changes are discernible to many elderly patients and their caregivers and may give rise to concern for underlying disease processes, such as dementia. With age there is a decline in episodic memory, the long-term memory system that stores past events or “episodes” with personal context. Examples of episodic memory include: “what did you have for dinner last night?” and remembering “where” and “when” a specific trip to visit grandchildren occurred. By contrast, procedural and semantic memory is stable and may even improve with age. Learning new information (fluid intelligence), processing speed, multitasking, task shifting, and executive function may decrease with age. Rates of cognitive decline vary between individuals and can affect the ability to live independently.

Vision declines with age as a result of changes in all the tissues of the eye: retinal aging is associated with macular degeneration and loss of central vision; optic nerve damage can result in glaucoma and visual field loss; and lens aging may lead to cataracts with characteristic noncorrectable decrease in visual clarity, haloes, and poor night vision. Age-related hearing loss (AHL) is a common condition in elderly adults. AHL or presbycusis is a degenerative, bilateral, and symmetrical process driven by intrinsic (e.g., genetics, cochlear aging) and extrinsic factors (e.g., noise exposure, ototoxic drugs) that can affect multiple types of cells involved in hearing. Olfaction may be impaired over time but is also associated with underlying processes, such as traumatic brain injury, Alzheimer disease, and Parkinson disease. Light touch sensation, vibration, and proprioception are also affected by age.

Cardiovascular

Maximal heart rate decreases approximately 6 to 10 beats per minute per decade and maximal oxygen consumption (VO _2max ) decreases 5% to 15% per decade after the age of 25 years. With aging, the cardiovascular system has decreased arterial compliance, increased systolic blood pressure, left ventricular hypertrophy with impaired filling, decreased beta-adrenergic receptor stimulation response, decreased sinoatrial node automaticity, and a decreased number of myocytes. The exercise-induced adaptations that occur in younger people, such as increased peripheral arteriovenous oxygen difference and increased cardiac size, stroke work, cardiac output, and left ventricular function, are not as available to the elderly. Older patients with coronary artery disease have age-related increases in left ventricular and arterial wall stiffness and thickening, which limit some adaptations with conditioning. In the operative setting, maintaining intravascular volume is important because the aged heart depends on preload more than in the younger person. Because afterload is increased by outflow tract stiffness, there is decreased sensitivity to catecholamines and impaired vasoconstrictive responses in the elderly.

Pulmonary

In the lung, surface area decreases as the alveoli and ducts enlarge resulting in impaired pulmonary gas exchange and ventilation/perfusion (V/Q) mismatch. In addition, there is loss of elastic recoil and lung stiffening resulting in increased lung compliance and decreased thoracic wall mobility in the elderly. Respiratory muscle strength also decreases. These changes lead to increased residual volume and functional residual capacity. Compensation during exertion can occur in healthy older adults to a limited extent.

Gastrointestinal

Peripheral and central age-related changes in the gastrointestinal (GI) system can lead to decreased appetite and energy intake and possibly malnutrition, the “anorexia of aging.” Smell and taste sensation may decrease with age, leading to loss of enjoyment from eating and reduced food variety. Gastric compliance decreases with age causing early satiety and prolonged postprandial satiety. Aging is associated with decreased stomach acid production (hypochlorhydria) and subsequent impaired absorption of vitamin B ₁₂ , calcium, iron, zinc, and folic acid. Hypochlorhydria can also lead to bacterial overgrowth in the small intestine. The microbial flora of the GI tract forms a symbiotic relationship with the hosts and aids in food assimilation and provides a natural defense barrier. The change in GI flora with age is not fully understood, but the microbiome is affected by medications, such as antibiotics. Cholecystokinin and leptin levels increase with aging and both have roles in suppressing appetite.

Genitourinary

Renal mass and blood flow decrease with age. Glomerular filtration rate (GFR) may also decline after the age of 40 years, and GFR estimates in general are not reliable for elderly women and those with low body weight. Aging also affects water balance as the kidneys are less capable of concentrating urine resulting in water loss. Urinary incontinence is common among elderly patients and more so in women, but is not a normal consequence of aging. Elderly individuals may continue to be sexually active. Although erectile dysfunction is common among older men, it is not a normal consequence of aging and underlying causes should be investigated.

Endocrine

Aging results in reduced hormonal secretion as well as tissue responsiveness. Anabolic hormones including testosterone, growth hormone, and insulin-like growth factor decrease with age, resulting in impaired muscle fiber protein synthesis and changes in body composition. These changes can result in decreased glucose tolerance. Decrease in estrogen with age (menopause) leads to collagen loss and thinning of the skin. Estrogen decline is also associated with bone loss, which may predispose postmenopausal women to osteopenia and osteoporosis. Change in tissue responsiveness to hormones and the complex interactions between hormonal systems may be part of the reason why hormone replacement therapy has not proven to be a straightforward approach to treat the effects of aging. Adrenal and thyroid levels may also change with age, but the clinical significance is not understood because the function of these systems appears to be robust throughout the life span, with the exception of disease processes.

Skin

Skin aging is caused by changes occurring during normal adult aging as well as insults from environmental factors. Age-related skin changes include thinning of the epidermis, decreased cell replacement, impaired immune response and wound healing, decreased moisture content, elasticity, blood supply, and sensory sensitivity. These changes increase the risk of skin disorders and injury to the skin in the elderly. Noncosmetic moisturizers in combination with humectants are effective for treating excessively dry skin in the elderly.

Medication Metabolism

Changes in pharmacokinetics and pharmacodynamics occur with age. Clinical drug trials are typically conducted with young and healthy age groups, and thus the reactions of the elderly to medications are not always the same as those of the population that was used to initially test the medication. Adverse effects are more frequent and may be more severe in the elderly. The increase in adipose tissue that typically occurs with age causes a larger volume of distribution for fat-soluble drugs and prolongs their biologic half-life. Conversely, total body water decreases by as much as 15% between 20 and 80 years of age, which decreases the volume of distribution of water-soluble drugs and thus results in a higher drug serum concentration. Hepatic drug clearance can be decreased up to 30% and renal clearance up to 50% in approximately 60% of elderly individuals. Care must be taken when prescribing renally excreted drugs in older and frail individuals. Patients with low muscle mass may have low serum creatinine levels leading to an overestimation of GFR.

Gait

Locomotion in older people is affected by multiple factors that are under the influence of aging processes: vision, cognition, motor control, balance, peripheral sensation, strength, joint health, and metabolic demands. It is also becoming increasingly clear that gait, cognition, falls, and dementia are interdependent processes. Overall, gait in the elderly is characterized by decreased speed, increased double limb support, shorter stride length, and a broader base of support. These characteristics are also associated with falls and the fear of falling.

Studies have shown gait speed to be a predictor of survival and possibly a biomarker of health status in relatively healthy older adults. A walking speed of 1.0 m/sec has been considered a guidepost for relatively good function and 0.8 m/sec predicting median life expectancy for age and sex. Baseline gait speeds vary among individuals, but are relatively stable until 65 years of age. The trajectory of gait speed decline varies among older adults.

In a longitudinal study of 2364 participants between the ages of 70 and 79 years, White et al. found that gait trajectories could be categorized as slow, moderate, and fast decline. Compared with their baseline gait speeds, individuals in the slow decline trajectory experienced a gait speed decline of 11% over 8 years, the moderate decline trajectory dropped 14% in gait speed, and the fast decline trajectory showed a slowing of 22% during the study period. The fast decline group was associated with increased risk of mortality. Therefore, age-related decrease in gait speed is not uniform and serial measurements of walking speed may be more informative because gait changes may indicate the presence of underlying pathologies.

History Taking

When examining elderly patients, questions should be directed toward the patient and not the caregiver or family member. Time management will be of concern when taking the history of patients with complex problems, but spending sufficient time and showing patience will help develop the patient-physician relationship and improve care.

The review of systems in the geriatric patient may be complex if the patient is experiencing problems in multiple systems. Focusing on recent changes in constitutional symptoms including fatigue, sleep, weight loss/appetite, pain, and falls may be particularly informative. Fatigue has multiple causes and warrants a thorough evaluation for the underlying cause(s). If sleep is impaired, what is the reason? Sleep management is different if the patient has pain, nocturia, or a mood disorder. Nocturia can result from the nighttime mobilization of peripheral edema. Urinary frequency, urgency, and subjective retention need to be identified and treated. Urinary incontinence should be excluded as a problem, and the examiner should bring up the topic because patients might be embarrassed about raising the problem. Is nutrition adequate? If not, is it because of a financial problem, being physically unable to get to a grocery store, being unable to carry food items back from the store, or being afraid of lifting hot items during cooking? When pain is a symptom, the history should specifically identify the sites and quality of the pain, as many older adults have multiple potential causes of pain.

Patients should be asked if they have fallen in the past year and about the circumstances regarding the fall. The frequency of falls, symptoms experienced at the time of the fall(s), and related injuries need to be determined. Those who report a fall within the past year are at higher risk for future falls. Questions about specific activities of daily living (ADLs) are important. Examples include: “Can you get in and out of a bathtub without assistance?” and “How often do you leave home?” Pain experiences or change in bowel or bladder function should be assessed because some elderly patients may assume new symptoms are as a result of “old age.”

Alcohol use needs to be assessed because alcohol may play a role in nutritional deficiencies and falls. Recognize that elderly patients might be having unprotected sexual intercourse with exposure to sexually transmitted diseases and that age alone does not preclude the use of illicit drugs. Does the patient have informal support systems such as neighbors who can be relied on for some degree of assistance? The history should also include a discussion of advanced directives. The patient’s goals and wishes should be a priority for the treatment plan and may be different from those of the patient’s family and caregivers.

Medication Review

All medications should be reviewed and medicine reconciliation should be performed at each visit. This is especially important if the patient is complaining of new or worsening constitutional and neurologic symptoms. Sedation, confusion, visual problems, insomnia, dizziness, headaches, fatigue, muscle pain, or cramps are some of the many possible common adverse effects of medications. Although these symptoms might not be considered “serious” adverse effects, they do impact function and quality of life and predispose patients to misdiagnosis and adverse events.

Given the risk of falls in the elderly, special attention should be paid to medication with central nervous system activity, such as antidepressants, benzodiazepines, and those with anticholinergic effects. Sleeping pills, antihypertensives, metoclopramide, tricyclic antidepressants, and antiepileptic drugs can cause cognitive impairment. The necessity and efficacy of each medicine should be considered along with renal clearance and potential drug-drug interactions. Is the patient taking the medications as prescribed? Because of the risk for drug-drug interactions, the patient should also be asked if they are taking nonprescription medications, supplements, or vitamins.

Physical Examination

In addition to the standard physiatric physical examination, there are some areas that physicians should be concerned with when evaluating elderly patients.

Neurologic disorders are particularly common causes of disability in elderly patients. Some neurologic changes are associated with normal aging, but abnormal examinations should not be automatically attributed to age-related changes, especially if they correlate with other symptoms or are a change from baseline. Psychomotor slowing, impaired balance, tremors, general loss of muscle or in myotomal distributions, sensory impairments, hypoactive deep tendon reflexes, impaired smell and taste, and change in bowel or bladder control may be difficult to assess in the context of preexisting conditions, and thus a patient and caregiver report is essential. Mental status assessment is a critical part of the geriatric examination and many different measures exist to assess functional status in the clinic setting, including the Mini-Mental State Examination. However, tests of executive function, such as the Executive Interview (Exit25), may correlate better with functional status and be more helpful for longitudinal tracking.

Lower extremity function and performance has good predictive value for disability in community-dwelling adults without disability. Tests of lower extremity function go beyond isolated manual muscle testing and should include balance measures (the Romberg balance test, single leg standing with eyes open or closed, tandem walking or standing, sitting balance); time to walk 8 ft; and rising from a chair five times. Formal balance testing may use the sensory organization test with dynamic posturography to determine whether deficits in the somatosensory, visual, or vestibular system are contributing to postural control problems.

The range of motion of the neck and shoulders should be thoroughly checked. Loss of shoulder internal rotation makes it difficult for the patient to get the hands to the back, as in attaching a bra strap. Loss of shoulder external rotation makes it difficult to get the hands to the top of the head for hair care. It is common to find limitations of hip extension and rotation in the elderly. This can have a negative impact on gait efficiency. In the patient with hip or low back complaints, the Ober test can be used to check for tightness in the tensor fasciae latae and iliotibial band. Limitations of knee extension and flexion should be identified because such losses of range of motion can have a major impact on the efficiency of gait. If decreased range of motion of the ankle is found, it should be determined whether it is caused by a joint capsule contracture, a bony block, or a tight gastrocnemius. Loss of ankle dorsiflexion range of motion that occurs only when the knee is extended is typically caused by tightness in the gastrocnemius. Ankle inversion and eversion range of motion is important for walking on uneven surfaces. Examination of the major joints for stability should be done.

Deformities of the feet are common in the elderly, such as a bunion (hallux valgus). Pes planus can also be present. Hallux rigidus can cause pain and interfere with gait efficiency. Hammer toes can be an incidental finding, a cause of pain, and a potential source of infection if skin integrity is not maintained. Skin calluses indicate the foot surfaces that are weight-bearing. Skin integrity is important in the feet for both prevention of infection and for comfort.

Frailty

Frailty can be defined as age- and disease-related loss of adaptation, such that events of previously minor stress result in disproportionate biomedical and social consequences. Fried et al. defined frailty as “…an aggregate expression of risk resulting from age- or disease-associated physiologic accumulation of sub-threshold decrements affecting multiple physiologic systems.” Or, more objectively, as the phenotype of a clinical syndrome in which three or more of the following are present: (1) unintentional weight loss of at least 10 lb over the past year; (2) self-reported exhaustion; (3) weakness (grip strength); (4) slow walking speed; and (5) low physical activity. Frailty was held by the authors to be distinct from both disability and from comorbidity, although frailty can be a cause of disability. The authors postulated that one pathway in the development of frailty could be attributable to the physiologic changes of aging, with a separate pathway attributable to diseases and comorbidities. The authors also identified an intermediate group of individuals (prefrail) whose risk over 3 years was more than double those with no frailty characteristics at baseline.

Other approaches assess the cumulative deficits in the frail individual with a frailty index, and several have been studied with different validities and predictive values. Frailty, despite the variation in assessment approaches, is a concept that clinicians recognize as a category of patients at risk for adverse outcomes.

Age-related muscle wasting is associated with decreased anabolic function, suggesting that anabolic pathways may be a target for therapy. Studies with exogenous testosterone supplementation have shown improvements in lean body mass, but also increased risk of cardiovascular adverse events. A phase II trial with a nonsteroidal, selective androgen receptor modulator (SARM) in healthy elderly men and postmenopausal women resulted in a dose-dependent improvement in total lean body mass and function. However, the effects on function and risks vary with the SARM tested. Stimulation of anabolic pathways increase cellular protein synthesis by upregulating the mammalian target of rapamycin (mTOR) pathway. However, exogenously increasing anabolism may have negative consequences on life span because inhibition of the mTOR pathway with rapamycin resulted in lifespan extension in male and female mice. Potential functional gains should be weighed with risks of cardiovascular events and decreased total life span in frail older adults.

Disuse and Immobilization

The overall decline in multiple body systems that comes with aging can be exacerbated by immobility. The effects of bed rest and immobility have been studied for several decades and have parallels with the physical repercussions of space flight. These studies have shown that it is the combination of inactivity and lack of mechanical loading that produce the characteristic negative effects of bed rest.

Head down–bed rest studies have ranged from 7 to 120 days and show that loss of muscle mass from bed rest varies between muscle groups with lower extremity muscles being more affected than upper extremity muscles. Bed rest also leads to a loss of strength and power, which is even greater than loss of muscle mass. Other effects of immobilization include increased muscle insulin resistance; increased bone loss from increased calcium excretion and decreased calcium resorption; decreased pulmonary function and exercise capacity; orthostatic hypotension; and impaired balance and coordination. Many of these conditions are already present in older adults, which suggest why immobility has more serious consequences for the elderly than for younger patients. Immobilization can combine with incontinence, skin fragility, and inadequate nutrition in the elderly to greatly increase the risk for pressure ulcers. Immobility from bed rest is a predictor of decline in ADLs, institutionalization, and death in hospitalized older patients. Vigilance is needed to prevent or minimize the immobilization of elderly patients unless absolutely required by their medical condition.

Falls

Falls are common in the elderly and a major cause of morbidity. Falls cause the majority of the fractures of the forearm, hip, and pelvis in the elderly and increase the risk of placement in a skilled nursing facility. There are multiple risk factors for falls, of which the physician should be aware ( Box 30-1 ).

Cognitive impairment and dementia increase risk of falls, possibly as a result of decreased cognitive reserve and limited attentional resources that impair multitasking, such as walking while talking. Impaired dual-tasking, as assessed with gait analysis, may be an objective marker of fall risk. High-risk medications for falls are those with central nervous system activity including antidepressants, antipsychotics, antiepileptics, benzodiazepines, opioids, sedatives and muscle relaxants, antihistamines, and anticholinergics.

Age-related changes in gait are associated with falling and fear of falling in the elderly and include reduced stride length and speed; increased double-support time; and increased variability in stride length and speed. Chronic back, hip, knee, and foot, which also affect gait, can increase fall risk. Pain is an important clinical sign that should raise concern for risk of falls, is usually assessed at each clinic visit, and can be linked to gait dysfunction by the rehabilitation specialist. Environmental conditions, such as dim lighting and high beds, can contribute to falls.

Fall prevention in the elderly has been studied in the acute care and community-dwelling settings with some distinctions between the two. Several systematic reviews of studies examining interventions to prevent falls or injuries related to falls have been performed. Recommendations to prevent falls and fall-related injuries are summarized in Box 30-2 .

Box 30-2

Recommendations for Fall and Injury Prevention in the Elderly

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  Fall risk assessment by qualified health care professionals or teams

  
  
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  Individualized, group, and home-based exercise

  
  
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  Balance, strength, and gait training exercise (e.g., tai chi)

  
  
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  Home safety evaluations and modifications

  
  
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  Medication review and reduction programs with family physician and patient involvement

  
  
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  Careful, medically directed tapering of high-risk medications

  
  
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  Addressing foot/ankle pain and dysfunction

  
  
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  Treating vitamin D deficiency (at least 800 international units per day)

  
  
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  Cataract surgery and dual chamber cardiac pacing if indicated

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