Assessment and Classification of Pain in the Elderly Patient
Introduction
Pain is common in the elderly patient, but it is greatly undertreated. Proper pain management can be complicated and can require a multitude of treatment options and modalities. Pain is the most common reason for physician visits annually,1 with the annual cost in the United States to be more than $50 billion.2,3 As the U.S. population ages, this number is projected to rise. The need for all physicians to become better equipped for diagnosing and treating pain is apparent.
Although it is clear that the elderly experience pain, they are often undermedicated because of the concerns for oversedation, decreased drug clearance, and the risk of drug-drug interactions.4 A study of acute burns showed the effects of age on narcotic dosing. In this study, patients over 75 years of age received significantly less opioid medications than patients age 66-75 years, who received less medication than patients age 55-65 years.5 Concerns of drug toxicities, drug interactions, and the patients’ fears of pain management are all factors in treating the elderly patient with pain, but these do not have to be barriers to effective pain management.
The Role of the Physician in Geriatric Pain Management
The role of the physician becomes increasingly important as mean survival rates increase and federal funding and access to healthcare decreases. The role of the physician in managing geriatric pain is outlined as follows:
• Diagnose pain syndromes. Physicians are apt to be more aggressive in treating pain when they have a known diagnosis.6
• Rule out life-limiting and life-threatening pain syndromes appropriately.
• Screen for pain, depression, and drug and alcohol abuse, and refer the patient to the appropriate treatment professional.
• Perform a functional status assessment. If the patient is hospitalized, assist him/her and/or the caregiver(s) in making decisions about returning home or entering a long-term care facility.
• Determine what additional support systems are needed, such as physical and occupational therapy services, a home health aide, or hospice services.
• Provide for assistive and adaptive equipment such as canes, walkers, wheelchairs, and orthotics. Adaptive equipment can markedly improve the function of the elderly pain patient.
In managing difficult geriatric pain syndromes, a team of healthcare professionals is required. The primary team consists of the primary care physician/geriatrician, pain management specialist, physical medicine and rehabilitation specialist, and occupational and physical therapists. Additional consultations may be required from a neurologist, neurosurgeon, orthopedic surgeon, gastroenterologist, psychologist, and drug and alcohol detoxification specialist.
Assessment of Pain in the Elderly
The initial treatment of pain begins with a thorough history and physical examination. A detailed history should include a description of pain characteristics,7 with specific inquiries on thyroid disease, hepatic and renal disease, diabetes mellitus, gastrointestinal disorders, psychological disorders, infectious disease, rheumatologic disease, and neurologic disease. Infectious diseases include Lyme disease, shingle infections, and meningitis. Rheumatologic disorders include rheumatoid arthritis, osteoarthritis, fibromyalgia, and osteoporosis. Neurologic review includes cerebrovascular accident, polio, and neuropathies. A review of any trauma or falls should be a routine part of every evaluation.
Since pain and suffering are subjective and individual to the patient, objective assessment can be difficult. Several pain scales exist to help to provide a quantitative estimate of the intensity of the patient’s pain. Visual analog scales, numerical scales, and verbal descriptive scales are widely used to evaluate pain in geriatric patients. The McGill Pain Questionnaire is a very comprehensive tool that can evaluate sensory, affective, and evaluative aspects of pain intensity.8 It is important that the individual bias of the practitioner not influence the care of the patient. Healthcare providers tend to underestimate pain. Studies show that only 30-55% of nurses are able to rate pain within one pain scale level of where the patients rate themselves when using the visual analog scale.9
A thorough review of systems including, but not limited to, the musculoskeletal exam, bowel and bladder functioning, sleep patterns, depression, and dementia should be performed (Table). In addition, a complex functional evaluation should be obtained. This should include questions about activities of daily living (ADL), assistive devices used for ambulation and ADL, current occupation or last occupation held, and the home physical environment. All social support systems should be invited to participate. It is important to know the driving status and recreational activities of the patient. A thorough neurologic and musculoskeletal examination should be completed, with particular attention paid to all areas of patient complaints, such as the spine, joints, muscles, and nervous system. The neurologic examination should consist of cranial nerve testing, identification of the corticospinal tract signs, evaluation of Babinski and deep-tendon reflexes, and a sensory examination for pin prick, light touch, and vibration in all sensory dermatomes and peripheral nerve distributions. Special attention should be paid to the sensory examination in complaints of neck or low-back pain or in those with a history of diabetes mellitus. Cerebellar testing and gait analysis are extremely important. Manual muscle testing should be performed. Proximal muscle weakness can be a sign of acute myopathy; therefore, dynamic muscle testing should also be performed, using squatting or stair climbing. The patient’s skin should be examined for evidence of herpes zoster infection. Bruising can be a sign of falling. A patient with diabetic peripheral neuropathy (DPN) should have a detailed foot evaluation. The physician should look for evidence of ingrown toenails, hyperpronation syndrome, and fractures that lead to Charcot’s joint deformities.
Classification of Pain
There are several ways to classify pain. The most common is to determine both the duration and pathophysiology of the pain. The duration classification determines whether the pain is acute or chronic. Acute pain has a purpose and is protective in nature. It has sudden onset and can be linked to specific tissue damage. It resolves with healing. Chronic pain persists after healing. It degrades health and functioning, and is associated with depression and anxiety.10,11 This can lead to decreased socialization, decreased appetite, and insomnia in the elderly patient.
The pathophysiology of pain can be classified into nociceptive, neuropathic, and mixed nociceptive-neuropathic pain syndromes.
Nociceptive Pain
Nociceptive pain is described as pain fibers that are stimulated by tissue damage, or potential tissue damage. Generally, it occurs outside of the neurologic structures. It is usually proportional to the stimulus causing it.12 Arthritis, mechanical back pain, fracture pain, sprains, strains, and ligament tears are examples of nociceptive pain syndromes.
Osteoarthritis is the most common nociceptive pain syndrome seen in the elderly patient population. Knee pain affects 20% of the population and is the fifth most common health complaint. It accounts for one million Emergency Department visits a year.13 Evaluation of osteoarthritis in the elderly patient is critical. Crook et al14 estimated a rate of persistent pain in patients with osteoarthritis who were over 81 years old to be 400 per 1000, whereas the rate for those age 10-30 was 76 per 1000. Osteoarthritis is a disorder involving one or several joints. Pain descriptors include aching, throbbing, and increased severity with movement and weight-bearing activities. Pain assessment and oversight is critical in patients with osteoarthritis since more than 20% of elderly Americans take analgesics several times a week, and compliance and adherence issues associated with dosage requirements and frequency are common problems.15,16
Neuropathic Pain
Neuropathic pain is pain that arises from damage or a lesion in the nervous system.17 Neuropathic pain may require little or no stimulus to cause significant pain. It usually can be traced to a specific nerve injury. In the elderly, neuropathic injuries can develop into pain syndromes such as postherpetic neuralgia (PHN), complex regional pain syndrome, thalamic stroke syndrome, and fibromyalgia. Other common neuropathic diseases seen in the elderly are diabetic polyneuropathy, sciatica, and other radiculopathies.
Pain descriptors include spontaneous pain, paresthesia, and dysesthesia. A paresthesia is usually an abnormal spontaneous sensation but not a painful sensation, such as tingling. A dysesthesia is a painful response that is spontaneous or evoked, as seen in sciatic pain. Patients with neuropathic pain will commonly have allodynia, a painful response to even the smallest amount of stimulus. An example would be patients with diabetes who have polyneuropathy and experience pain from bedsheets at night. Neuropathic pain is usually constant but can be worse at night. It can also be described as a spontaneous burning, shooting, and lancinating sensation. When a noxious stimulus is introduced to the patient, he/she can exhibit hyperalgesia, an exaggerated response to a normally noxious stimulus. In extreme cases, hyperpathia, an explosive response to a normally non-noxious or noxious stimulus, can be provoked.18
It is theorized that neuropathic pain syndromes develop when the brain is no longer able to dampen the pain stimulus coming from the periphery and spinal levels because of damage done to the peripheral or central nervous system. This allows a marked increase in substance P and glutamate at the dorsal horn of the spinal cord that will go unchecked. When the inhibitory signals to the dorsal horn of the spinal cord are overwhelmed, the dorsal horn becomes hyperexcited, leading to an abnormal elevation of the processing of pain in the patient. This phenomenon is referred to as “central sensitization” or “central amplification.”19,20
DPN and PHN are common neuropathic pain syndromes seen in the elderly. It is estimated that 2.7 million Americans have peripheral neuropathy as a complication of diabetes mellitus. 21 The likelihood of developing DPN increases with the age of the patient, the duration of the disease, and the glycemic control of the patient.22 DPN is a progressive disease that begins with sensory loss in the extremities that can ascend with time. Eventually, the upper extremities can be involved. Allodynia can be a complaint early on in the disease, especially at night. Insensate feet lead to repeated trauma and eventual ulceration and Charcot’s joint deformities.
Although diabetes mellitus is the most common cause of peripheral sensory neuropathy, there also exist nutritional, toxic, and infectious causes of peripheral neuropathy as seen in HIV infection. Thiamine deficiency can be seen in alcoholics and in patients with renal failure. The incidence of chronic neuropathy in alcoholics is about 9%.23 Chemotherapeutic agents such as cisplatin can also lead to dose-dependent painful peripheral neuropathies.24
PHN is a long-lasting pain syndrome following the acute rash manifestation of herpes zoster (shingles) infection. PHN is primarily seen in the elderly and in immunocompromised patients. The risk of developing PHN after shingles infection dramatically increases with the age of the patient, as does the morbidity of the disease.25 Patients present with severe allodynia in the region of the rash. Since herpes zoster becomes activated at the sensory ganglion of the peripheral nerve, the rash and pain will follow a sensory dermatomal pattern on physical exam. The thoracic nerves are most commonly involved, followed by the ophthalmic division of the trigeminal nerve.26 If the nerve is unable to regenerate or too much damage occurred, chronic PHN pain results. It is not uncommon to see hyperpathia, especially when the trigeminal nerve is involved.
Mixed Nocicepetive-Neuropathic Pain
Mixed nociceptive-neuropathic pain syndromes are a combination of both nociceptive and neuropathic features. Spinal stenosis in the elderly population is a common example. Lumbar spinal stenosis is a narrowing of the vertebral canal, involving both the spine and the spinal nerves and nerve roots. Patients will experience nociceptive pain from facet joints and spinal ligaments. Neuropathic pain occurs when the spinal nerves are also compressed. Approximately 1.2 million individuals in the United States have leg and back pain associated with lumbar spinal stenosis.27 Degenerative lumbar stenosis pain increases with age secondary to the formation of bone spurs and bone overgrowth at the aging spinal canal. Other causes of spinal stenosis are herniated nucleus pulposus and slippage of vertebrae developing a spondylolisthesis. In advanced cases, patients will describe neurogenic claudication, pain in the back that radiates to the legs that is relieved with bending forward. The patient can describe leg numbness and even weakness after ambulation of relatively short distances. This must be differentiated from vascular claudication, where the patient usually must sit down and stop all activities to reconstitute blood flow to the ischemic lower extremities. Degenerative lumbar stenosis requires treatments that will address both the neuropathic leg pain and the nociceptive back pain.
Other mixed pain syndromes in the elderly include cervical spinal stenosis, piriformis syndrome (where both the piriformis muscle and the sciatic nerve are involved), and cancer pain.
Summary
Physicians and healthcare providers must assess all of their elderly patients for pain. It is important to distinguish between acute and chronic pain. Not treating patients’ pain can lead to decreased socialization, depression, and insomnia. Assessment of pain should be done without bias because providers tend to underestimate the pain of the patient. A thorough neurologic and musculoskeletal exam should be performed. Pain should be classified as nociceptive, neuropathic, or mixed. Once classified, a unique pain management program can be structured for the patient.
Two other articles in this issue (“Pharmacologic Management of Pain in Older Patients” and “Alternatives and Controversies for Pain Management in the Elderly”), the latter of which is available online at www.clinicalgeriatrics.com, will summarize treatment options for elderly patients who have chronic and acute pain. Pharmacologic, interventional, and holistic treatments will be outlined. Finally, specific treatment problems seen in treating pain in the elderly will be addressed.
The authors report no relevant financial relationships.
Dr. Jermyn is Associate Professor and Chair Designate, Dr. Janora is Associate Professor, and Dr. Surve is Assistant Professor, Division of Rehabilitation Medicine, NeuroMusculoskeletal Institute, University of Medicine and Dentistry of New Jersey, School of Osteopathic Medicine, Stratford. Dr. Surve is also from the Department of Osteopathic Manipulative Medicine.
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