Acute Pain Management Considerations in the Older Adult

Sarahbeth R. Howes

Tyson Hamilton

Elyse M. Cornett

Alan David Kaye

Introduction

Many treatments for chronic pain in the older adult are not well studied related to limitations of the patient population. Limitations include society’s stigma in assuming pain is a part of aging, frail patient population with presumably multiple comorbidities, and polypharmacy associated with treating comorbidities.¹,² Nevertheless, pain is reported in 60% independent and 80% dependent long-term geriatric patients.³ Despite a high incidence in the elderly, pain is most likely underreported between the assumption that pain is related to aging, communication barriers in patient-physician exams or provider-staff assessments, poorly identified pain attributing it to another preexisting comorbidity, cognitive impairment, patient anxiety to report pain as it may reflect the progression of current, preexisting disease or fear of addiction to prescribed medications, and physician fear of prescribing due to polypharmacy.¹,²,³,⁴

The World Health Organization (WHO) current guidelines for treating pain includes a stepwise approach, beginning with nonopioids for mild pain, adding a weak opioid for moderate to severe pain, or replacing it with a strong opioid if pain relief is not achieved, classifying the pain as severe.³,⁵ Pain in the geriatric population can be thought of in two ways: cancer-related vs non-cancer-related.³ Opioid use is efficacious for cancer-related pain; however, pain management options for non-cancer-related pain are small.³ Geriatric non-cancer-related pain is most identified as arthritic pain, such as osteoarthritis and rheumatoid arthritis.³ In addition, postherpetic neuralgia (PHN) and chronic systemic disease-induced pain are also common causes.¹,³ The pathophysiology behind the pain produced by each of these conditions is different, yet the options for treating pain remain nonetheless the same.

In addition to the different modalities of pain, there are several limitations of elderly patients. The pharmacodynamics and pharmacokinetics in the older adult are heavily researched, all of which show how aging impacts the ability to metabolize common analgesic medications.¹ Given the prevalence of diabetes and heart conditions, it is difficult to combat pain management with current medications, like nonsteroidal anti-inflammatory drugs (NSAIDs), which are associated with cardiovascular and renal complications.¹ Not to mention the overall increase in depression and dementia within this age group, whose neuronal pathways are newly identified as overlapping with pain neuronal pathways.⁶

Evidence shows a relationship between chronic pain and a patient’s outlook in management, especially if that outlook is bleak.¹ For example, a study showed patients receiving a total knee arthroscopy (TKA) who underwent a one-time perioperative Acceptance and Commitment Therapy (ACT) workshop decreased opioid use and achieved pain relief faster than the control group who did traditional standard of care treatment.⁷ Group-based education and exercise are not inferior to individualized cognitive functional therapy in pain reduction.⁸ Current international guidelines for chronic low back pain (CLBP) suggest psychological therapy
in addition to exercise.⁹ With this evidence, geriatric pain is best relieved when using a multimodal, biopsychosocial approach¹,⁸,¹⁰ (Fig. 25.1).

FIGURE 25.1 Elderly patient using the physical support of a walking cane due to uncontrolled pain. (Drawing by Rachel Glenn, medical illustrator.)

Treatment/Management

Importance of the Basics: Proper History and Physical

Treatment management must first begin with a proper history and physical to best identify and characterize the type of pain ailing the patient. Lack of knowledge on how to evaluate pain in older adults, especially those who are dependent on staff-provider communications because of assisted living or long-term care facilities, can be a major hindrance in correctly assessing the type of pain.⁴ The likelihood of this pain resulting from current comorbid conditions or previous surgeries is high.¹ Authentic patient history is important when considering pharmacological treatment options, which will be limited by other medical conditions and possible drug interactions. A good quality physical provides background when considering roles of other treatment teams, such as physical therapy, occupational therapy, psychological intervention, or interventional therapies. From there, the physician can identify the patient’s attitude regarding pain and align treatment options with goals of care.

Nonpharmacological Management

When considering rehabilitation, it is important to understand rehabilitation programs are utilized with the goal to restore function; however, if restoration is unlikely, the treatment can be focused on improving patient disability.¹ For instance, it is well known from studies dating back to the 1990s that strength-training exercises can improve pain and mobility in patients with osteoarthritis.¹ Properly educated and supervised patients are more likely to adhere to recommended training, with encouragement and group exercises increasing positive social interactions and overall hopefulness toward possible pain resolution.¹ Physical therapy has proven to block the transduction of pain signals from the peripheral nervous system to the central nervous system (CNS).¹ Providers must contemplate these nonpharmacological, lower-risk treatment modalities and consider their ability to compliment pain regression through a biopsychosocial approach, perhaps even before considering more risky pharmacological options.

Pharmacological Management

Physiologically, pain begins as a signal at the peripheral nervous system and is eventually transduced to the CNS.¹ This process involves a chain of signals before reaching the CNS. Their individualized activation stimulus highlights the importance of correctly identifying the type of pain. Pharmacological management options discussed will follow the stepwise approach currently advised by WHO.

Mild pain: nonopioid management

Acetaminophen

Acetaminophen is the first-line recommended agent for mild pain. While the mechanism of action of acetaminophen is not fully understood, it is accepted that acetaminophen works at both the central and peripheral levels.⁵ Centrally it is thought that acetaminophen inhibits pain by stimulating the descending serotoninergic pathways.⁵ Molecularly it is thought that acetaminophen acts specifically within the peroxidase site of bifunctional enzyme prostaglandin H synthase (PGSH), cyclooxygenase (COX).⁵ Through this, the enzymatic disruption results in peripheral inhibition of COX.⁵

Acetaminophen is particularly helpful in treating musculoskeletal pain and has a good safety profile (high quality of evidence, strong recommendation).¹⁰

In contrast to opioids, acetaminophen has a ceiling effect; however, it is proven up to 4 g of the drug does not result in evidence of hepatic dysfunction or outright failure.³ Important considerations for use include recognizing acetaminophen, like most drugs, is metabolized by the liver. It is recognized that an aged liver may delay the clearance of drugs.¹⁰ Of note, acetaminophen use is an absolute contraindication in patients with liver failure.¹⁰

In contrast to NSAIDs, acetaminophen does not have any anti-inflammatory properties, strictly acting as an analgesic and antipyretic.³,⁵ This disadvantage is detrimental given that the top geriatric non-cancer-causing pain conditions in the elderly are arthritic inflammatory diseases like osteoarthritis and rheumatoid arthritis.¹¹ Further research also suggests that uncontrolled inflammatory pain can result in a cycle of pain due to the induced neurogenic inflammation. Direct tissue injury, as seen with “wear and tear” diseases like osteoarthritis, results in inflammation mediators through the conversion of arachidonic acid into prostaglandins and stimulation of nociceptors that transmit the brain to the CNS.³,¹²

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