The incidence of cancer increases with age. In the United States, the rate of malignancy in the older population is nearly 10-fold that in the young, being 2,183 per 100,000 population for people over 65 versus 224 per 100,000 for those under 65 (15). However, cancer-related pain is less well recognized and treated in older persons, and the need for clinicians to facilitate symptom control for elderly patients with cancer is anticipated to steadily increase. As described in Chapter 45 by Burton and Phan, people with cancer may have multiple causes of pain, resulting in deterioration in function, nutrition, and mood. Older individuals may be reticent to seek treatment for pain, and may be reluctant to take medications for pain (16); many other barriers to effective pain management have been highlighted, as discussed later. A study of 1,308 outpatients with metastatic cancer revealed higher reporting of poor pain control in older patients; age over 70 years was predictive of inadequate pain management, with an odds ratio (OR) of 2.4 (17). Data from more than 13,000 aging patients with cancer discharged from hospital to nursing homes revealed that one-third had ongoing daily pain, and, of these, one in four did not receive any analgesic medication (18). Despite ongoing pain, patients older than 85 years were half as likely to receive morphine as those aged 65 to 74 years.

Educational programs targeting clinicians, patients, and caregivers have been identified as a means to improve inadequate cancer pain management in older persons.

In parallel with the occurrence of cancer, the rate of surgical and anesthetic interventions increases with age, with a concomitant increase in numbers of aging patients requiring postoperative analgesia. A survey of anesthetic practice in France during 1996 indicated that the annual rate of anesthetic procedures had increased since 1980, particularly in older age groups, to 25% to 30% of men and 19% to 24% of women over 65 years, compared to an overall rate of 14% (19). Notably, the rate of regional anesthesia rose markedly, to 23% of anesthetic procedures in 1996. As expected, the American Society of Anesthesiologists (ASA) status generally increased with age, reflecting increased comorbidity, although the largest group had ASA II status, indicating the variability of health in the aged. Surgery for ophthalmic, urologic, vascular, cardiac, and pulmonary procedures was more frequent in older patients. It is anticipated that the rate of surgery will continue to increase proportionally in older age groups, relative to the young. Regional anesthetic techniques are frequently used in these older individuals, notably for orthopedic, genito-urologic, abdominal, and gynecologic surgery, and for postoperative pain control that optimizes cognitive function.

Postoperative pain management, surveyed in general terms in Chapter 43 by Macintyre and Scott, is often poorly addressed in the older patient. An analysis of the impact of pain on morbidity after hip fracture in 411 cognitively intact patients with a median age of 82 years indicated that 50% of patients experienced moderate to severe postoperative pain, and 87% received no regular analgesia (20). Increased postoperative pain, but not total opioid dose, was associated with longer hospital stay, delayed ambulation, reduction in rehabilitation, and function impairment at 6 months. Analgesia prescribed only on an as-needed (p.r.n.) basis was associated with increased length of stay and time to ambulation. Some studies indicate that older patients receive less postoperative analgesia (21,22).

One way of examining the effects of biological aging on pain perception is to use psychophysical measures, most of which have examined pain threshold. A meta-analysis undertaken on age differences in pain threshold has clearly demonstrated an increase in threshold with age, when measured using brief thermal stimuli (25). This increase in pain threshold is attenuated somewhat by increasing the duration of the thermal stimulus, but the difference still persists (26). The central nervous system is also involved in aging processes, and the effects of descending nociceptive inhibitory pathways in the brainstem have also been examined for age-related differences (27). Using a cold immersion technique, it has been shown that young people recruit a descending inhibitory system. In older people, recruitment of these inhibitory pathways was less effective, and increases in pain thresholds were limited in comparison to younger
persons. This difference suggests that older people are less able to tolerate a persistent painful stimulus; other literature also supports this concept (25). Overall, therefore, with aging there appears to be diminished function of those descending spinal pathways that modulate the perception of noxious stimuli in the cerebral cortex. The precise nature of these effects remains unexplained; they may be structural or functional in nature. Age-related changes in the pharmacodynamics of central endogenous opioid actions are likely to contribute to these findings (28).

There also appears to be age-related impairment in pain perception mediated differentially by Aδ and C-fibers (29), and in the effectiveness of temporal summation at a spinal cord level (30). Older people rely less upon well-localized Aδ activation and more upon poorly localized C-fiber activation, before reporting the presence of pain (29).

Many age-related diseases are associated with pain. Conversely, many clinical studies of pain and aging suggest there may be reduced pain with increasing age in conditions such as myocardial ischaemia, postoperative and procedural pain, inflammatory disease in the abdomen, and pain associated with malignancy (31). However, these latter findings, generally derived from clinical audit studies, may be misleading because of difficulties in controlling for severity of pathology and uniform application of measurement tools.

Functional declines with age that are the result of environmental effects on cohorts are often difficult to detect. Nevertheless, scrutiny of the literature on prevalence of chronic pain with age by body site reveals distinct differences. Hip, knee, and foot pain increase in prevalence with age as opposed to visceral causes of pain; these joint pains are considered often to be related to physical work in men and ill-fitting shoes in women.

The presence of multiple pathologies in older people must be considered in planning an approach to pain management. Both active and inactive comorbidities, in addition to physical and cognitive impairments such as visual impairment, deafness, loss of dexterity, gait impairment, and memory loss need to be taken into account. One also has to ask the question: Is the treatment appropriate for the older person? Specific objectives and treatment goals may vary as a function of age. It is likely that the goals of care will be symptom control and, wherever possible, functional independence rather than cure. The empowerment of patients and caregivers is very important in this age group. It must also be remembered that older cohorts often are unfamiliar with psychological approaches. Some older adults have low self-efficacy for psychological treatment objectives. There are also age-related differences in beliefs and attitudes toward pain. Older people often consider pain to be a normal companion to aging, rather than attributing pain to disease, and they are often focused on past regrets instead of future prospects. The social reinforcers of pain behavior often differ from those seen at younger ages. Litigation and avoidance of work responsibility are much less evident, whereas the need for social contact, the effects of widowhood, and the solicitous spouse may influence behaviors in response to pain.

An interesting but unanswered question is whether disuse affects the pain experience. Over the last several years, the question of stoicism as it relates to age has been studied (32,33). One attribute of stoicism includes reluctance to label a noxious stimulus as being painful. Older pain-free subjects subjected to an experimental pain stimulus may be reluctant to describe the stimulus as painful. However, when such stoicism is assessed across a wide age range in patients with pain, no age effect is observed. This suggests that reluctance to label may be a consequence of disuse in this age group, due to limited recent experience of pain.

Any assessment of the older patient in pain should lead to a formulation that includes medical, functional, social, cognitive and mood-related domains (Table 48-1).

The support of concerned relatives is often helpful in the rehabilitation of chronic pain sufferers. However, excessively solicitous behavior by relatives and caregivers can result in a worsening of chronic pain and pain behaviors. For example, if a spouse insists on undertaking activities for the patient, deconditioning may occur, resulting in exacerbation of musculoskeletal pain. An expectation of solicitous behavior on the part of the patient can also result in social conflicts. The evaluation should also consider the possibility of caregiver stress, which may adversely impact on the patient’s pain severity or cognitions. Social (including economic) factors in pain management are covered in greater detail by Loeser in Chapter 29.

Available measurement tools for delirium and dementia do not provide the specificity to differentiate between these conditions nor assign to each a percentage contribution when both are present with enough reliability to enable their use in clinical situations. The clinician relies on clinical acumen to determine the time course of onset of cognitive impairment and the ancillary factors of variability in attention and change in conscious state. Asterixis, or metabolic flap, may be helpful, if present in the examination of the patient with suspected delirium, in raising awareness of an organic mental syndrome.

Given the high prevalence of chronic pain and delirium/dementia among older people, these two problems often coincide. There are many causes of delirium and dementia, and even within a single diagnostic group individuals differ in regard to their cognitive and communication abilities. Dementia is usually associated with impairment of memory, thus compromising the ability to give a pain history. Cognitive impairment is often associated with language impairment; for example, aphasia in vascular dementia and increasing paucity of vocabulary in advanced Alzheimer’s disease. Multiple observations may be required for accurate and reliable diagnosis, and a separate history should be sought. The inability of an individual to recall or report pain does not exclude the possibility that her pain is sufficiently severe to warrant treatment.

In patients with delirium and dementia, pain is poorly recognized, difficult to document, and undertreated (36,39,40,41). The inability of some older people to express their pain and the perception of some clinicians and caregivers that pain is less severe in individuals with cognitive impairment are important barriers to effective pain management in patients with dementia (41). Pain in older people with communication difficulties may present as either silent withdrawal or aggressive agitation, often alternating in the same individual. The first step is adequate assessment for the presence and impact of pain. The problem of severity assessment increases as dementia worsens. For patients who are communicative, the pain intensity scales used in cognitively normal older people are still relevant. There is no consensus as to which scale is the most appropriate in older individuals. There is some suggestion that word descriptor scales are able to be completed more frequently than numerical rating scales in communicative individuals with moderate to
severe dementia. It is best to try a number of different scales, and select the instrument the person appears to manage best. In this way, most people with significant cognitive impairment or moderate to severe dementia are still able to have their pain assessed with some degree of accuracy and less observer bias.

In noncommunicative older individuals, as in infants, observer interpretation of pain behavior is used. Some features include facial expressions, such as brow lowering, orbit tightening, raised upper eyelids or eyelid closure; others relate to vocalizations, guarding, or protective posturing, and altered motor activity. Measures and audit tools for these behaviors continue to be developed (36,40,41,42).