Pain Management in the Elderly: Etiology and Special Considerations
The United States is on the verge of what is referred to as a “longevity revolution”—a phenomenon that is occurring as the population of elderly individuals (aged 65 years and older) increases. Currently, 12% of the population, or 38 million Americans, fall into this category. By 2030, it is projected that the number of elderly individuals will reach 72 million, approximately 20% of the US population. In addition, individuals over 80 years of age are the fastest growing age group worldwide.1
The growing elderly community is at high risk for chronic pain conditions. The Institute of Medicine report, Relieving Pain in America, has highlighted the fact that the prevalence of pain has been increasing among all age groups but is consistently greatest among elderly Americans.2 It is estimated that approximately 30% of the elderly population suffers from chronic pain.1 Typically, elderly patients are more likely to report pain in multiple locations, and elderly women are more likely to report pain than elderly men.3 Moreover, these older Americans have the highest long-term rate of consumption of medications for pain.2
The good news is that many elderly individuals are very productive and remain active.4 The Centers for Disease Control and Prevention has reported that the majority of adults aged over 65 years continue to work, volunteer for humanitarian causes, travel, and remain relatively active. Individuals who have aged successfully have the following traits5:
- Avoidance of debilitating diseases and disability
- High physical functioning, which enables them to live independently and engage in normal daily life activities
- Maintenance of cognitive function by actively engaging in mentally-stimulating and challenging activities, and pursuit of social and productive activities
- Resilience to cope with physical, social, and emotional changes
- Perception of control over life circumstances
In Part 1 of this two-part series we will discuss the etiology of pain conditions. Part 2 will review treatment considerations.
Special Concerns in Elderly Populations
Assessment of pain in the elderly population raises special considerations. It is widely believed that the elderly are less sensitive to pain and that pain is a normal part of the aging process, leading to possible under-treatment of pain.6 In addition, many elderly patients may downplay their pain in the face of other significant events, such as loss of independence or death of a spouse, or comorbidities, such as diabetes and heart disease.7 Studies have shown, however, that loss of a spouse (mourning, depression) has been associated with increases in the likelihood of pain.8
It appears that certain pain conditions increase with age (ie, degenerative joint disease), whereas others decline with age (those that have a work-related mechanical component). An increase in the prevalence of persistent pain,9 joint pain,10 and central sensitization syndromes such as fibromyalgia11 have been reported in the elderly.6 It appears that chest, upper back, stomach, and headache pain do not change in prevalence throughout a person’s lifespan, whereas abdominal and orofacial pain that is unrelated to mechanical use tend to decrease in prevalence as one ages.3 In addition, older adults generally have a higher number of painful comorbidities, such as diabetic neuropathies, osteoarthritis, fractures and injuries from falls, compression fractures from osteoporosis, and impaired circulation, that are directly related to painful symptoms.12
Many physiological changes through the aging process can increase pain and affect quality of life. These physiological changes affect the skin, bones, joints, and the urinary, muscular, hormonal, sensory, vestibular and cardio-respiratory systems. In addition, elderly patients have age-related issues, including memory problems, dementias, increased use of multiple medications, and different nutritional needs than younger patients.4,13,14 A review of physiological changes related to aging and pain are highlighted here.
Alterations of body composition are a common part of the aging process. In particular, the elderly usually have an increase in fat mass and a decrease in lean body mass (ie, any body mass that is not fat, such as bones, muscle, organs, water weight, etc.), which results in thinner skin and loss of skin elasticity due to the skin fat deposits being redistributed into the trunk.4,15 This loss of elasticity will cause the skin to sag and lose color by the fifth decade.4 The loss of some of the protective fatty layer in the skin that helps cushion one’s blood vessels leads to easier bruising from burns and injuries.16 This redistribution of fat from the skin to the organs, as well as increased water retention and decreased blood flow, affects how medications are metabolized in the body: drugs may remain longer and break down slower. This means that pain medications may take longer to be effective, but does not necessarily mean that their effects will last longer; it depends on what the medication is used for.12 However, because the medication may take longer to be effective, it can create a tendency for patients to consume higher doses than required or advised.
The sensory systems also start to become compromised through the aging process. Vision becomes less sharp as the lens of the eye begin to harden and lose transparency, and the pupil gradually shrinks to allow less light to penetrate.4 Cataracts and glaucoma are more likely to occur.4 In addition, hearing ability decreases, particularly the ability to hear high-frequency consonants (eg, s, t, and z).4 Loss of sight and hearing also raises the risk for falls and accidents that can be painful.
Tactile sensation, such as changes in pain perception, vibrations, cold, heat, pressure, and general touch sensations decrease due to decreased blood flow and increased nerve damage due to higher blood sugar levels.12,17 Decreased temperature sensitivity increases the risk for conditions such as hypothermia or frostbite,4 which means that special care must be taken for the elderly living in cold-weather climates to prevent these painful conditions and that cold/heat therapy for pain management must be carefully monitored to prevent damage.
Neuropathies and other conditions also can compromise an elderly individual’s sensory systems, with common symptoms of struggling to maintain a steady gait and balance increasing the incidence of fractures due to falls.12
The urinary system also becomes less efficient through the aging process, in part because of increased prescription medication usage. At the age of 70, kidneys are 50% less efficient at waste filtration than at age 30.4 Patients also may need to urinate more frequently. This occurs because the bladder’s capacity reduces by half from age 30 to 70.4