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Pain Assessment


Pain Assessment

Article Author:
Alexander Dydyk
Article Editor:
Sundeep Grandhe
Updated:
10/24/2020 5:53:59 PM
For CME on this topic:
Pain Assessment CME
PubMed Link:
Pain Assessment

Introduction

Pain is the most common complaint seen in a primary care office. There are over 50 million Americans, 20 percent of all patients, that suffer from chronic pain in the United States.[1] The prevalence of chronic pain is even higher in the elderly.[2] With opioid use disorder on the rise, it is critical to treat a patient's pain in a logical manner adequately.

Part of the pain assessment is defining whether a patient's pain is either acute or chronic. When severe pain lasts longer than three months, it is generally considered to be chronic. Determining if the pain is acute or chronic pain is an important distinction because as pain transitions from acute to chronic, pain becomes centralized, or a function of the central nervous system rather than peripheral. Pain becomes maladaptive with hyperalgesia, and allodynia becoming more prevalent. Tissues texture becomes hypertonic, ropy, and cold. Pain is often more dull and achy rather than sharp. 

How we assess pain has long term implications for our patient's morbidity and mortality. With over 30 percent of patients reporting pain lasting longer than six months, providers should have multiple tools at their disposal to define a patient's pain to treat their symptoms better. An estimated eight percent of adult patients and six percent of children suffer from chronic pain that causes significant limitations in function and quality of life.[1][3]

Effective treatment modalities for acute, chronic, centralized, or neuropathic are often different. Ten percent of the United States population complain of neuropathic pain. This population may benefit from a serotonin-norepinephrine reuptake inhibitor (SNRI) such as duloxetine, as compared to ibuprofen for an acute injury.[4][5] Chronic pain is among the leading causes of disability and lost work hours in the United States. Billions of dollars are lost due to loss of productivity. Thus standardized pain assessment tools are an objective way of monitoring a patient's symptoms, as well as their recovery.

An important aspect of the pain assessment is in the acknowledgment of the influence of various comorbidities and psychosocial determinants of health that impact pain. Comorbid mood disorders lead to worsening pain, and the treatment of said mood disorder improves a patient's pain. Prior history of opioid dependence, IV drug use, sexual abuse, trauma, old age, chronic diseases, and economic disparity all contribute to a patient's pain. Cultural influences on pain also play a role.[6][7][8]

Anatomy and Physiology

Acute pain is nociceptive pain. This type of pain originates in the peripheral nervous system, where pain receptors synapse in the dorsal horn of the spinal cord and travel along the spinothalamic tract until they synapse in the thalamus. When a pain signal reaches our central nervous system, action potentials fire. Once a threshold is achieved, we experience pain. Separately, pain can be neuropathic or centralized. 

As pain becomes chronic, over three to six months of acute pain, pain can become centralized. Centralized pain requires a lower threshold to experience pain. Decreased thresholds are problematic. Pain is an adaptive response to a painful stimulus. A lower threshold for pain subjectively means pain can be experienced from non-painful stimuli (allodynia), or mildly painful stimuli experienced can be experienced as severe pain (hyperalgesia). Centralized pain is a maladaptive form of pain.

Neuropathic pain is the dysfunction of the somatosensory tract of the nervous system, rather than the spinothalamic.[9][4] Centralized and neuropathic pain often coincide but are not mutually exclusive. Neuropathic pain can be both peripheral and centralized. Centralized and neuropathic pain are both considered gains in function (pain). They both play a role in the development of chronic pain.[10][11][12]

How we treat pain is a function of the pathophysiology of the type of patient's pain. Some types of pain respond to modulating neurotransmitters or ion channels, while others are more receptive to opioid neuroreceptors.

Indications

Intuitively, pain is a subjective experience, and thus many elements of the biopsychosocial components during history taking are critical. A stoic patient with acute pancreatitis may rate their pain severity a four out of ten, while a more histrionic patient with wrist strain states there pain is an eight out of ten. Neither patient is wrong, and it's a subjective measurement.[13] Objective measures of pain, especially chronic pain, help create a standardized way to orient patients and providers to their pain, with the ultimate goal of improvement of pain and patient outcomes such as function and quality of life.

An essential first step in the pain assessment is distinguishing nociceptive pain from neuropathic. Pain characterized as burning, shooting, pins, and needles, or electric shock-like point the differential towards a neuropathic origin of the patient's pain.[14][15][16] Sharp or throbbing pain is more likely to be acute nociceptive pain.

Contraindications

The various aspects of the patient's life may affect treatment decisions. For instance, pregnancy is often associated with low back pain, and pregnancy can complicate the choice of medication treatment options for chronic pain, particularly the use of opioids.[17]

It is critical to not focus solely on the numerical value of someone's pain. Often, it is necessary to prompt a patient to explain the numerical scale of pain. A 1/10 pain being a minor bump or bruise, while 10/10 pain being the worst pain they have ever experienced on par with giving birth or passing a kidney stone.[18] If a patient complains of 9/10 pain, this does not mean they automatically warrant opioid analgesia.[19] They may very well benefit from less potent analgesics tailored to treating the underlying cause.

Equipment

To fully assess the location of a patient's pain, a body diagram map can be completed. Ankle sprains are solitary, acute injuries. Body diagrams may not be necessary in such a case. Localized pain is different than whole body pain. Yet, in a patient with multiple comorbid pain disorders such as fibromyalgia, centralized pain disorder, and rheumatoid arthritis, distinguishing between the numerous locations of a patient's pain, as well as factoring the radiation of their pain, is difficult. However, it is an essential part of guiding therapy. In a patient with widespread pain, how are providers supposed to distinguish new pain complaints from the chronic? A body diagram map helps the distinction. Is the patient with multiple comorbidities experiencing a rheumatoid arthritis flare, or is it a reactivation of pain secondary to knee osteoarthritis. A body diagram helps to decipher multiple different types of pain.

A fibromyalgia survey can also be used to help distinguish a new pain complaint from a patient's comorbid fibromyalgia as well.

Functional MRI and various imaging modalities can be helpful in a pain assessment.[20][21]

Personnel

Both the primary care provider and specialists often need to review previous records related to the patient's pain complaint in detail. Records usually include imaging, mental healthcare related therapies such as cognitive-behavioral therapies, past surgical history, and previous medications used. For example, if a patient with neuropathic pain secondary to diabetic peripheral neuropathy had failed gabapentin therapy, the reason for the medication failure must be noted. Inquire if it due to the side effect profile. Ask if gabapentin had caused too much sedation or if the medication not provides the expected pain relief. If the drug did not work, determine the dose before stopping. If the patient with diabetic peripheral neuropathy was on 300 mg twice a day of gabapentin, then the patient was only on a fraction the maximal dose before stopping. Gabapentin's failure in the treatment of neuropathic pain usually is concluded after 1800 mg daily, not 600 mg in tolerating patients.

Furthermore, nonpharmacological therapies such as virtual reality, acupuncture, physical therapy, and invasive treatment modalities such as neuromodulation can be utilized. The patient's records need to be obtained. Failures and success of these various treatment modalities must be defined.

Preparation

How a provider approaches their patient, their receptiveness, and empathy they show can significantly impact patient outcomes. The relationship made between the provider and the patient has a lasting impact on the improvement of a patient's pain. Studies have shown that physician support and empathy improve pain and the wellbeing of patients.[22][23]

Technique

There are multiple acronyms used to obtain the history of a patient's pain. Some of the most commonly used abbreviations are "COLDERAS" and "OLDCARTS. Both of these acronyms summarize the character, onset, location, duration exacerbating symptoms, relieving symptoms, radiation of pain, associated symptoms, and severity of illness.

A multidimensional assessment of a patient's pain and the severity of their pain can be completed. A Pain, Enjoyment, General Activity (PEG) tool can be used to aid the multidimensional assessment of patients in pain.[24] The PEG score focuses on function and quality of life. A chronic pain patient who experiences daily 7/10 pain is treated with both pharmacological and nonpharmacological therapies. Following treatment, their pain is 5/10. A few points might not seem like a significant difference, but if their enjoyment and quality of life, as well as function, are improving, treatment may have had a profound impact on the patient's life. The PEG tool is scored 0 to 10 for each category. The higher the score, the worse the function and uncontrolled pain.

The Four-item Patient Health Questionnaire or PHQ-4 is a combination of the PHQ9 and GAD7 assessment tools used to evaluate depression and anxiety, respectively.[25] The PHQ-4 should be used as a screening tool for all cases of chronic pain. If the score of the PHQ-4 is more significant than five, then a full GAD-7, PHQ-9, and the Primary Care PTSD screening tools are recommended.[26] 

The Defense and Veterans Pain Rating Scale (DVRPS) is a five-item tool with a 0 to 10 out pain scale, as well as an assessment of the impact of pain on sleep, mood, stress, and activity levels.[27]

In children self-reporting a behavioral observation scales are used to assess pain.[28] Age-based rating scales of pain can be used. Visual analogs are also often implemented. Typically visual analogs are done with pictures of faces in various degrees of distress.  By adolescence, children usually can rate their pain on a numerical scale, similar to adults.[29] 

The Pediatric Pain Questionnaire and the Adolescent and Pediatric Pain Tool are used to assess the location of a patient's pain as well. The patient is asked to draw on the body map where they feel pain.[30] The ideal age group is age 10 for these tools. 

Observational pain assessment tools are used in populations who cannot self-report. The facial expression, fussiness, and distractibility, ability to be consoled, verbal responsiveness, motor control are observational findings used in such an assessment tool. Observational pain assessment in infants or young children can use the (r-FLACC) tool.[28][31] The tool is an acronym for Revised Face, Legs, Activity, Cry, Consolability.[32][33] Multiple other validated tools can be used, the one that is better than another is the NAPI tool. However, multiple tools have been used and are validated.[34][35][36][31]

Nonverbal children with neurologic impairment (NI) is a challenging population to assess pain. Caregivers are often needed to help determine changes in the patient's behavior. Grimacing, moaning, increased muscle tone, crying, arching, atypical behavior such as aggressive behavior are a few symptoms to monitor in this population. Nonverbal children with NI include the Revised Face, Legs, Activity, Cry, Consolability (r-FLACC) scale, and the Individualized Numeric Rating Scale (INRS). The assessment adds specific behavior for atypical presentations.[32][35]

Complications

A family history of mental health disorders, chronic pain disorders, or substance abuse puts patients at higher risk of developing chronic pain.[37][38][39] 

An overlooked aspect of the management of pain is the influence of sleep hygiene, stress, exercise, and diet play in the recovery of an injury.

Catastrophizing about pain can be a symptom of severe and debilitating pain. There is real fear associated with pain that can be all-consuming for a patient. Ironically, this hyperfocus on pain often makes the subjective experience of pain worse, not better.[40]

Underserved communities are at increased risk for the development of chronic pain, substance abuse, and opioid dependence. When assessing a patient's pain, it is essential to be mindful of the area of your practice. Multiple factors contribute to the increased risk, including limited access to care and socioeconomic status. Local culture in specific geographic regions has a much higher percentage of the population on chronic opioids. The approach to assessing pain also changes for adults, children, the disabled, and the elderly.[41][42][43]

Failure to complete physical therapy after only attending two sessions for shoulder pain is not the failure of treatment — moreover, its noncompliance. This is why it is critical to assess the effect of therapy. Stopping therapy because a patient does not wish to go to their appointments is very different than completing all sessions and continuing to have persistent pain. It is a complication of a poorly obtained pain assessment.

Observational assessment underestimates self-reported pain scores.[44] 

Hunger and stress levels also impact pain severity.[45]

Clinical Significance

The long term impact of two to three days of acute, postoperative nociceptive pain, pales in comparison to the centralized pain and their long term impact it can have on a patient's quality of life. Part of the pain assessment is categorizing the type of pain the patient is experiencing. How the pain is described is high yield. Ask if the pain is burning or sharp, and if it is constant or intermittent. The descriptors matter. Examination findings also increase the likelihood of one type of pain over another. If the patient is experiencing symptoms of allodynia or hyperalgesia, this point away from acute pain and suggests a centralized process.[46][47]

Providers must discuss with the patient the expectations for therapy, as well as the need to teach patients about their pain. Various surgical procedures may put a patient at an increased rate of developing chronic pain. Breast surgery, for example, has a higher likelihood of chronic pain compared to knee placement.[48][49]

Assessment of pain is not a one-time occurrence. It narrows the differential diagnosis. It is a way to monitor therapy, as well as changes to pain over time. Chronic pain disorder, although appropriate as a diagnosis in some circumstances, is not a blanket label for all patients experiencing prolonged pain.[50] It is essential to treat comorbid health conditions in all pain complaints. It improves patient outcomes.

Enhancing Healthcare Team Outcomes

An interprofessional team that provides a holistic and integrated approach to pain management can help achieve the best possible outcomes for the patient. If there is a specific underlying cause of a patient's pain, it must be determined. The role of the primary care providers in the management of acute and chronic pain, as well as the various comorbidities associated with pain, is essential. Specialists are often needed to manage various pain disorders. Neurologists, Pain Medicine specialist, orthopedic surgeons are but a few specialists who are apart of a pain assessment. Furthermore, palliative care or supportive care medicine specialists, physical therapists, occupational therapists, and cognitive-behavioral therapists also play an integral role in pain assessment. Pain assessment tools can be used in an inpatient or outpatient setting and be incorporated into the management of multiple scenarios ranging from post-operative pain, palliative pain, acute injury, or chronic pain disorders. Adequate pain management in both in an acute and chronic setting lead to better patient outcomes. It is critical to optimize a patient's care by managing their pain with various nonpharmacological, pharmacological, and interventional treatment approaches. 

Collaboration shared decision making, and communication is key elements for a good outcome. The interprofessional care provided to the patient must use an integrated care pathway combined with an evidence-based approach to planning and evaluation of all joint activities. The earlier signs and symptoms of a complication are identified, the better is the prognosis and outcome. The primary way to prevent chronic pain is adequate treatment and assessment of acute pain.

Nursing, Allied Health, and Interprofessional Team Interventions

Various questionnaires should be administered at the beginning of each patient visit depending on the patient's age and associated comorbidities.

Nursing, Allied Health, and Interprofessional Team Monitoring

Various pain assessment tools can be used upon each visit to monitor change in pain over time, as well as response to treatment.


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