Chronic Pain in the Elderly: Mechanisms and Perspectives

Abstract

Chronic pain affects a large part of the population causing functional disability, being often associated with coexisting psychological disorders, such as depression and anxiety, besides cognitive deficits, and sleep disturbance. The world elderly population has been growing over the last decades and the negative consequences of chronic pain for these individuals represent a current clinical challenge. The main painful complaints in the elderly are related to neurodegenerative and musculoskeletal conditions, peripheral vascular diseases, arthritis, and osteoarthritis, contributing toward poorly life quality, social isolation, impaired physical activity, and dependence to carry out daily activities. Organ dysfunction and other existing diseases can significantly affect the perception and responses to chronic pain in this group. It has been proposed that elderly people have an altered pain experience, with changes in pain processing mechanisms, which might be associated with the degeneration of circuits that modulate the descending inhibitory pathways of pain. Aging has also been linked to an increase in the pain threshold, a decline of painful sensations, and a decrease in pain tolerance. Still, elderly patients with chronic pain show an increased risk for dementia and cognitive impairment. The present review article is aimed to provide the state-of-art of pre-clinical and clinical research about chronic pain in elderly, emphasizing the altered mechanisms, comorbidities, challenges, and potential therapeutic alternatives.

Keywords: chronic pain; elderly; life quality; management; mechanisms; perception.

FIGURE 1

Pain perception and experience in the elderly. The pain perception in the elderly is complex, with biopsychosocial factors associated. The older individuals present opposite sensitivity for heat and mechanically evoked pain. This population apparently tolerates acute pain (postoperative and cancer pain, peritonitis), when compared with persistent pain states. For chronic pain diagnosis in the elderly, health professionals should consider that older adults demonstrate particularities such as superior pain acceptance and self-efficacy, with less catastrophizing levels. However, the elderly has altered peripheral and central sensitization combined with higher levels of anxiety, depression, and insomnia. Social support from a family member or a caregiver, distraction, sedentary life, and dementia can influence the pain experience of older people, leading to changes in pain unpleasantness.

FIGURE 2

Pain and specific comorbidities in the elderly. There is evidence of a correlation between pain syndromes and comorbidities in older individuals. Viral infections in elder patients with comorbidities has been associated with chronic pain. Parkinson’s disease induces higher hypernociception and widespread pressure pain, low back pain, and depression, and pain likely precedes the motor symptoms. Also, persistent pain has been related to the appearance of depression and memory deficits in older people. It has been proposed that elders with osteoarthritis are at higher risk to develop Alzheimer’s dementia. Older women with burning mouth syndrome diagnosis demonstrated cold and warm hypoesthesia, small fiber neuropathy, with higher levels of anxiety and depression, in a condition that is typically misdiagnosed in seniors.