Hi, my name is Melissa Wymer. I will be giving a lecture today about the basics of chronic pain and chronic pain evaluation, which is part of the PCSSO chronic pain curriculum. This training is a combination of lectures written by Dr. Dan Alford, Dr. Roger Chow, Dr. Sudden Savage, Dr. Kevin Severino, and myself. Our educational objectives today, at the end of this activity, you should be able to identify pain mechanisms, describe how to perform a pain assessment, review the impact of psychosocial factors on the pain experience, and recognize the effect of mental health on the pain experience. So we're going to go through a case that will span throughout this lecture. This case is of a patient you're seeing for the first time for evaluation of chronic pain. This is a patient who hasn't had any recent primary care or other care for the last six months. She is a 45-year-old female. She has obesity, essential hypertension, tobacco use disorder, and 20 years of constant low back pain that radiates down her left leg. The pain that she has is described as aching and burning in the low back and pins and needles in both feet. The pain is worse in her low back. She has had some previous imaging which showed an L4-5 disc herniation, however there was no lumbar stenosis seen. She is prescribed extended release morphine, 15 mg twice a day, and she also takes acetaminophen as needed. She attempts to walk daily for 15 minutes. The question we are going to ask today is how do you thoroughly and properly assess this patient's pain? On this slide you will see several components of a pain assessment. We're going to go through these different components throughout the module in much greater detail, but in general we are going to focus on evaluating the comorbid conditions which may be contributing to this patient's pain. We're going to think about different psychosocial factors such as mental health, social, and substance use that may be contributing to her pain. We're going to perform a thorough history and physical just like you would for any other symptom that you would encounter in medicine such as dizziness or fatigue. Like you would for any of those symptoms, you're going to do a thorough assessment. You're going to ask about certain characteristics such as the nature, location, duration, intensity of the symptom, the aggravating and alleviating factors. You're going to talk about past or ask her about past or current pain treatments. You're going to want to ask about how this pain is affecting her life and her function by some of the characteristics listed there. You're going to want to know what her expectations of pain treatment and pain symptom management are. Additionally, you're going to think about other potential contributing factors such as vitamin deficiencies which may be contributing to her pain. You're going to evaluate certain factors such as B12, vitamin D, or iron which do tend to be frequently deficient in this patient population. Finally, you're going to want to understand what her current physical condition is and what her current functional core strength and other factors are. As I mentioned, these symptoms, low back pain, foot pain, headaches, these are all symptoms not diagnoses. In order to determine what the pain generators are and the type of pain are, we really need to thoroughly evaluate and this will guide the where, what, and how we approach the treatment. There are two main pain classifications that is nociceptive pain which is somatic or visceral pain and then the other broad category is neuropathic pain. Determining if pain is nociceptive or neuropathic again is going to guide your treatment so we're going to go through that. Here's a slide showing pathways for nociceptive pain. In nociception or nociceptive pain, there is typically a stimulus, high intensity stimulation in the periphery that transduces a pain signal to receptors in the dorsal horn of the spinal cord and that transmits along nerves across the synapses in the spinal dorsal horn to the brain where there is a lot of rich synaptic interconnections and this, as the neurons go up the spinal cord, there is perception within the brain and the perception, how we perceive pain, causes modulation which can actually amplify or inhibit the signal and listed here are some of the various mediators of what can increase or decrease our pain experience. Nociceptive pain is typically, as I said, somatic or visceral. Examples of somatic pain are low back pain, osteoarthritis, myofascial pain, typically described by people as sharp, stabbing, localized aching, burning or throbbing. Visceral pain is a type of pain related to an organ so this is typically peptic ulcer disease, myocardial infarction or pancreatitis are some examples. Generally, people may describe this as quite very generalized, achy, crampy or a pressure type pain. The second broad category is neuropathic pain and neuropathic pain occurs due to aberrant, sometimes spontaneous conduction along nociceptive pathways with or without active tissue injury. So with neuropathic pain, you can actually have transmission of painful stimuli without there actively being ongoing tissue injury and that is shown here. Some examples of this are listed on the left, different types of neuropathies, neuralgias, phantom limb pain and central sensitization which we will talk about a little bit later. Here are some other common etiologies of neuropathic pain. Additionally, post-herpetic neuralgia, radicular pain, complex regional pain syndrome fits in this category. You can have AIDS related neuropathy, spinal cord injury, post-stroke pain are all examples of neuropathic pain and again it matters because the treatment for these conditions is going to be different if it's neuropathic pain as opposed to nociceptive pain. For the diagnosis of neuropathic pain, patients generally describe their pain as burning, tingling, electric, numb or shooting pain. A patient might be quite sensitive to cold, heat and touch. You might see changes in hair, nail or skin. Typically, this is associated with different balance problems. Patients might feel unsteady on their feet. Your physical exam would want to look at touch, vibration, pinprick, cold and warmth, sensation and really assess for different factors of allodynia and hyperalgesia. If there are changes in any of these factors, that might indicate that you're dealing with more of a neuropathic pain as opposed to a nociceptive pain. You're going to want to rule out common causes of neuropathic pain which could be vitamin B12 deficiency, diabetic neuropathy. If a patient has not had a thorough evaluation of these factors, you might want to perform those. In severe neuropathic pain, you may consider nerve conduction studies or MRIs if there are other factors associated such as muscle weakness or other very severe symptoms. As I mentioned, there are several different components of a pain assessment. We're going to go through these in depth and they are listed here. We're going to talk about how do you subjectively assess someone's pain, how do you do a thorough sociopsychobiological assessment, how do you thoroughly and quickly assess mental health and substance use disorders. For pain assessment, there are two types of subjective pain assessments that can be done. There are unidimensional pain scales and then there are more sophisticated multidimensional instruments. The unidimensional pain scales are typically numeric ratings of 0-10, 10 being the worst type of pain. There are different visual analog scales where patients can define how they feel based on those scales. There are visual analog scales where they can identify their pain based on a face or a grimace. These are very subjective. They do not generally affect or tell us anything about the patient's functional status. The multidimensional instruments are helpful though could be impractical for routine use in a primary care setting for instance. These are the McGill Pain Questionnaire, the Brief Pain Inventory, which though says it's brief, can take a patient quite a long time to do. The most brief and probably most easy for patients to use and the most able to be integrated into a primary care practice would be the Pain, Enjoyment, and General Activity Scale which we will go over. These multidimensional scales are helpful because they're really giving us more information about the pain and the pain experience. We think they can actually help guide treatment better. As I mentioned, the socio-psycho-biological assessment is very important to understand to really get a sense of how is the pain being experienced, what different social, psycho-biological factors might be changing that pain perception in the brain. This is going to be different factors or things that you're going to ask the patient about are really how has pain affected their quality of life? How has pain affected their sleep? Do they regularly get good sleep? Do they have good sleep hygiene? What's their health literacy of pain? Do they understand any different ways of treating pain? Have they learned that you shouldn't, say for instance, that you should go to bed or have bed rest once you have low back pain? These are certain health literacy issues that you might have to help educate them about to understand that actually we know now it's better to be quite active when you have low back pain. You're going to want to talk to them about conditioning and function. What's their typical day like? Are they engaged in any activities that would actually promote physical conditioning? Many times patients are quite minimally active and this can really contribute to their pain. What types of life experiences have they had? What type of suffering, other issues are they going through at this point in time in their life? How does this affect meaning and their experience of pain? These are going to be important things for you to know. Did this patient recently have significant grief? Are there other types of life experiences that have really affected this person? Additionally, understanding some about their self-efficacy I think is important. Does this patient believe he or she can work with or through the pain? Do they really feel like there is improvement for them in the future? Do they feel like they're the key to getting better? These are important questions to ask. Questions about coping and acceptance. How are they coping with the pain and how the pain has affected their life? Different environmental stressors. Does the patient potentially have pending homelessness or other financial issues that might be affecting them? Certainly friend and family dynamics and support can be very influential on a patient's experience of pain. Their work history is important to know. Has the person worked in the last 15 years? What types of disability factors might the person be facing? Is the person really wanting to work but not able to? Is that affecting their pain experience? Finally, I think we're starting to know more about biogenetics and how genetics can actually lead or contribute to a person's pain experience and how maybe familial factors may also contribute. Doing a mental health and substance use assessment is very important in this pain evaluation and we're going to talk about how to do this effectively to address or uncover potential symptoms of depression, anxiety, PTSD, as well as substance use disorder. I mentioned the PEG scale. This is what it looks like. This was done by Aaron Krebs and a really important study and scale to use and easily integrate into primary care. It basically asks these three questions. What number best describes your pain on average in the last week? What number best describes how during the last week pain has interfered with your enjoyment of life? What number best describes how during the past week pain has interfered with your general activity? It's not super descriptive but in three quick questions you can get a pretty good sense of how pain is affecting this person's life. When screening for depression probably the fastest screen to start with is the PHQ-2 and this is based on these two questions over the past two weeks. How often have you been bothered by any of the following problems? Number one, little interest or pleasure in doing things, feeling down, depressed, or hopeless. A positive score would be a score greater than three and if the patient had a positive score you would want to administer the longer questionnaire called the PHQ-9. And certainly assessing for other mental illness that we're also going to go through. There are longer depression assessment tools such as the Depression Inventory or the Inventory of Depressive Symptomatology. These are generally available for use. Again, they might not be as easy to integrate into a primary care setting due to their length but these might give you a better sense of the severity of the person's depression or how mental health is affecting them. I think PTSD tends to be probably an under-recognized contributor to chronic pain in our society and so this primary care PTSD screen called the PC-PTSD can be a really quick tool to be able to determine if there are any factors of PTSD that could be contributing or mediating the patient's pain experience. And so it asks in your life, have you ever had any experience that was so frightening, horrible, or upsetting that in the past month you have had nightmares about it or thought about it when you did not want to, tried hard not to think about it, or went out of your way to avoid situations that reminded you of it, were constantly on guard, watchful, or easily startled, felt numb or detached from others' activities or other surroundings. So a positive screen would be any three yes answers. And if they did answer yes to these, you would want to follow that up with potentially additional questioning. A very brief screening, so part of the screening and brief intervention is looking for unhealthy substance use with two single questions, one for alcohol and one for drugs. So for alcohol, you can start asking the question or give a questionnaire, do you sometimes drink beer, wine, or other alcoholic beverages, and follow that up with, because most people do in general, so follow that up with how many times in the past year have you had five drinks if you're a man, four drinks if you're a woman, or more drinks in a day. And if they answer one or more, basically greater than never, that would be a positive answer to that question and you might want to follow that up with an audit or another type of questioning to better understand if there might be an alcohol use disorder going on or unhealthy drinking. For drugs or illegal drugs, the question that has been validated is how many times in the past year have you used an illegal drug or used a prescription medication for non-medical reasons? And again, a positive score would be if it's ever been greater than never. Again, you would follow this up with additional questioning. You could use a validated questionnaire such as the DAST or other types of questions. Okay, so let's go back to our case. Remember that this patient was having low back pain, diabetes, and was having some aching and burning pain in the low back and pins and needles in the feet. So she describes the pins and needles sensation in a stocking distribution. She does have a pretty strong family history of diabetes mellitus type two. She has gained 20 pounds in the last five years. Her function has worsened with her pain. Her PEG results show that she has very high pain, eight out of 10 on average. Her enjoyment of life is very low, one out of 10. And she's describing a lot of pain interference with her activity, so pain is interfering eight out of 10 for the last two weeks. Her PHQ-2 result is a four, which is positive, so would need to be further evaluated with additional testing. She also screens positive for the PTSD screen, which would also be something you'd want to follow up with. She does answer no to screening questions for alcohol and drugs and basically has never been using alcohol in excess and denies use of drugs. She denies a family or personal history of substance use disorder. She states that she has very poor sleep. She's only sleeping about three to four hours a night. And she tells you in her evaluation that she has a history of aggravated sexual assault when she was 21 and has never married as a result of that. So this is a lot of information that you're able to obtain with some key questions, which really can help you understand her pain better. You follow up your history with a thorough physical exam. And on that physical exam, you find that she has normal vital signs. Her weight is obese. She weighs 265 pounds. She appears depressed and is tearful at times. She has several pain behaviors, such as rubbing her back throughout the exam. She denies any suicidal ideation. She has a normal cardiopulmonary exam. Her spine has normal alignment. There's no spinal point tenderness, but she does have a positive straight leg raise. You test her muscle strength, which is five out of five in the upper and lower extremity. But her muscles are very tender to touch in a very generalized general region. She is unable to walk heel to toe due to some imbalance, but she has normal gait otherwise. She does not have an Achilles tendon reflex bilaterally. And you perform a diabetic foot exam, which does not show any lesions, alterations. And she has normal pulses, but there is a loss of protective sensation by vibration and pressure. And I should mention that she is not known to previously have diabetes. So you follow this up with some labs in your office, and you do find that she actually has a very high hemoglobin A1C, 9.5%, which would put her in the diabetic range. And this, again, was not a previous diagnosis. She has a very low vitamin D, less than 10. She also has a low B12 of 200. And you check liver, kidney function, and electrolytes, and those are all normal. So based on your evaluation, you're able to give her the following diagnoses. You're able to say that she has myofascial low back pain, which is nociceptive in nature. She has some features of lumbar radiculopathy, which is a neuropathic type of pain. She likely has diabetic neuropathy, which is a neuropathic type of pain. And she also has symptoms of central sensitization, which is a neuropathic type of pain. This was included by her sort of generalized muscle tenderness throughout, as well as her severe pain, which has been increasing over time. She additionally has very low hypovitaminosis D and B12. She does appear to be quite physically deconditioned and clearly has obesity. She meets criteria for having depression, which needs further evaluation. She likely has PTSD, which could be related to her prior sexual assault. She has clearly a reduced quality of life and very poor sleep. So we're able to see that for a patient coming in with these symptoms, we're able to really better characterize all of the different factors here that could be contributing to her pain experience. So let's now talk about sociopsychological impact of pain and psychiatric comorbidities and how that can change pain experience. So before we start getting into that entirely, I want to show some graphics of how, to better illustrate this, how there are lots of different things that contribute to pain based on socio and psychological factors. So this was a study done in 1994 in the New England Journal of Medicine, which looked at 100 people. And of those 100 people who all had MRI findings, such as bulging, degenerative discs, or herniated discs, they saw that in this population, many of them with these MRI findings were actually pain-free. So when the patient didn't know that there were these findings, they did not actually describe pain. So many of the people who had very concerning, if you will, MRI findings, actually did not describe pain. So this pathology does not always correlate with pain. Expectations of pain can change the pain experience as well. So this is a description of a builder, age 29, who came to an accident. Or sorry, this is someone's description of this patient. So there was a builder, and when the paramedics came to the accident, the emergency department, after he had jumped on a nail, he was very, very painful as the smallest movement of the nail was painful. He was sedated and given fentanyl and midazolam. The nail was then pulled out from below. And in describing this, Fisher says, when his boot was removed, a miraculous cure appeared to have taken place. Despite entering proximal to the steel toe cap, the nail had penetrated between the toes. The foot was entirely uninjured. So the patient was experiencing extreme pain. However, the nail had actually never entered his foot, but the expectation that the pain was going to be very severe was causing such severe pain that he needed to be medicated. Here's a description of how the meaning of pain can inhibit pain by Henry Knowles Beecher from 1946. And he states that in World War II, he had speculated why 3 quarters of men badly wounded in battle declined morphine while similarly injured accident patients in Boston required high doses. He perceived the meaning of injury modulated the pain. He said that strong emotions can block pain. For the soldier, the wounded, or sorry, for the soldier, the wound releases him from an exceedingly dangerous environment to the safety of the hospital. His troubles are over, he believes, and he becomes euphoric. So you can actually, pain can actually lead to a positive experience for a patient if it is in some way freeing from a dangerous situation. Here's another way to put this, that chronic pain is complex. And for one patient, although physical injury could be the main mediator or cause of pain, for another patient, physical injury could be quite small and other factors such as genetic, social disability, depression, substance use could worsen pain. So both patients have eight out of 10 pain. However, as you can see, the thing that is sort of contributing to the pain can be quite different in their experience and how they experience the pain. This is also shown here that chronic pain is shaped by several different factors. As we've been saying, the socio-psychobiological factors can mediate the pain and can actually change the physiologic stimulus. So the different factors being all of those we mentioned before, sleep, social context, incentives, acceptance, self-efficacy, et cetera. Another way to look at this is the neural matrix or the pain neural matrix. This is another conceptual model that was developed by Roberts that basically shows that there are several different inputs to the pain neural matrix, all of the various inputs we've been talking about. And those go into a pain neural matrix, which the outputs of which are pain perception and pain behavior, and those can all contribute again to the experience of pain or the feeling of pain. We talked a little bit about central sensitization. So again, all of these various factors can contribute to the very complex thing that we're now starting to understand more, which is called central sensitization, which is heightened dorsal horn excitability due to increased peripheral nociceptive activity. So the features are that you have a reduced threshold for dorsal horn neuron activation, and that's coupled with an increased receptive field of dorsal horn neurons, an increased response of dorsal horn neurons to painful stimuli. So all of these factors together actually can increase the pain experience, the actual pain transmission in the spinal cord, even though the peripheral nociceptive input may not be very large. And that is because of these changes that are occurring in the spinal cord itself and in the central nervous system. And then finally, another way to think about this is what we call adaptive versus maladaptive pain. So adaptive pain really contributes to our survival by protecting us from injury and promoting healing when injury has occurred. However, maladaptive pain is an expression of the pathologic operation of the nervous system. It actually is pain as a disease. Maladaptive pain is the expression of abnormal sensory processing, and usually is persistent or recurrent. And so essentially in maladaptive pain, and I think you could call this central sensitization, as well, the fire alarm system is constantly switched on. So the central nervous system fire alarm system is constantly on, and even though there's no emergency occurring, you're getting these repeated false alarms. And so this is contributing to a very severe sensation or pain sensation. And then finally, there are other things contributing here to our experience with pain, and we see this sometimes as the fear avoidance cycle. So as pain progresses and gets worse, these other factors such as fear of injury or re-injury, fear of movement, less movement, deconditioning, all contribute to the pain experience as well. And then social isolation can sometimes occur. And all of these together contribute to this very severe, the severe pain syndromes that we're seeing in our patients. So there are different risk factors that can put people at risk to develop chronic disease, the chronic disease of chronic pain. Some of the ones that have been documented in the literature and described are patients who have concomitant mental health diagnoses, those who are marginally employed or vocationally dissatisfied, people with history of abuse, emotional, physical, sexual, or interpersonal violence. This is particularly profound with those people who have childhood adverse experiences, such as abandonment, emotional neglect, or abuse. Personal and family history of substance use also is a risk factor for the development of chronic pain, as well as certain concomitant medical conditions place patients at risk and can definitely contribute to the development of chronic pain. So who do we think is most vulnerable to this disease of chronic pain? And we really think this is the socio-psychologically vulnerable. So this is not always accurate, but people who seem to be more prone to developing chronic pain are people who have a lower education, lower socioeconomic status, rural populations who might have less access to appropriate medical care, might have more farming injuries or other types of injuries, those who are cognitively compromised, those who are psychologically compromised, might have limited support system, they might be somewhat psychologically inflexible, have severe depression, those who are marginally employed or vocationally dissatisfied. If there's a history of abuse or interpersonal violence, there tend to be increased rates of pain. This could be manifested by history of abandonment, emotional neglect or abuse, many times in childhood, personal or family history of substance use disorders, there's a high correlation between having a substance use disorder and developing a pain syndrome, poor health status, and then some of these abnormal brain connectivity structure, spinal cord injuries, other types of strokes or other type of cognitive impairment. The relationship with psychiatric comorbidities is quite profound, so the prevalence of pain, I'm sorry, the prevalence of depression in patients who have chronic pain is quite high, same with anxiety, personality disorders, PTSD and substance use disorders, as we said, various studies listed here showing that. There's a lot of overlap between psychiatric symptoms and pain, so psychiatric symptoms can be manifested as having negative affect, regulation, a lot of difficulty sleeping, poor concentration, low energy, psychomotor retardation, decreased interest and suicidal ideation can all worsen or contribute to the pain experience. So how are patients with depression and chronic pain different from patients with pain who don't have depression? Well, compared to patients with pain without major depressive disorder, patients who did have major depressive disorder and disabling pain had significantly poorer quality of life, greater somatic symptom severity, a higher prevalence of panic disorder, and a six-fold greater prevalence of anxiety. So definitely worse outcomes in this population in regard to these different factors. Another question, is there a difference in treatment response in patients with pain and co-occurring depression? Patients who have both tend to have poor adherence to treatment. It might be harder for them to follow a complex treatment plan. It might be harder for them to engage in certain active activities, such as physical therapy or exercise. They tend to have worse satisfaction with treatment, higher likelihood for relapse and inability to improve, and really less chance for functional improvement because of these factors. We also think that PTSD and chronic pain can amplify each other. So pain can serve as a reminder of trauma, which can amplify PTSD avoidance behaviors. You can get physiological arousal in response to traumatic recollection, can also amplify pain and lead to pain-related avoidance. You can get, that can lead to more physical deconditioning and increased odds of the patient having severe pain or a worse pain experience. So in summary, what we know about psychiatric comorbidity and chronic pain is that depression and anxiety are the most common psychiatric disorders seen in patients with chronic pain. Patients report more severe pain and disability, are less likely to adhere to treatment and have poor outcomes. And attention to assessment and treatment of chronic pain and concurrent psychiatric disease is necessary to improve treatment outcomes. And then finally, in summary for this entire lecture, a comprehensive pain evaluation has several components as we've described, including a thorough history of pain, sociopsychobiological assessment, mental health and substance use assessment and physical exam. Sociopsychological factors and psychiatric comorbidities are important mediators of pain origin, pain experience and pain treatment. Additionally, I'd like to let you know about an ACP lecture series called ACP Caring for Patients with Chronic Pain, Treating with Opioids, Balancing the Benefits and Risks Before Starting Opioids video, which can be another nice addition to the lecture that we just went through. Here are the references listed here, along with information about PCSSO, Colleagues Support Program and LISTSERV, where you can access mentors to help you with questions you might have around prescribing, along with some information about PCSSO trainings in general. Thank you so much for your attention.

chronic pain

pain evaluation

pain assessment

psychosocial factors

mental health

nociceptive pain

neuropathic pain