Chronic pain in a family doctor practice – meaning, assessment, and therapeutic options

INTRODUCTION

Pain is an incredibly common and widespread phenomenon encountered daily both in medical practice and in our everyday lives outside of professional duties. We distinguish 2 types of pain, primarily considering the duration of its occurrence. Acute pain typically occurs briefly, lasting no longer than a month, while chronic pain persists for more than 3 months [1]. In practice, this is not always easy to determine. Among many chronic diseases, pain may occur periodically, allowing it to be classified based on the aforementioned time criterion as acute, but it often recurs. An example of such a situation is headaches in migraine. Therefore, in cases where recurrent painful symptoms constitute the sole manifestation of a disease, many clinicians and pain researchers are inclined to refer to it as a chronic condition. It is worth mentioning other differences between acute and chronic pain, including better response to both pharmacological and non-pharmacological treatment, the absence of permanent consequences, greater intensity, or a different reaction to perceived sensations [2]. The aim of this review is to systematise the current knowledge regarding the clinical assessment of pain, its impact on the functioning of the central nervous system, and methods for pain treatment – both pharmacological and non-pharmacological. Inadequate assessment and insufficient pain relief are common issues that we wish to highlight, as pain affects billions of people worldwide every day. Its prevalence, along with the associated disability and mortality, makes pain a significant global health burden [3].

MATERIAL AND METHODS

This publication is based on scientific publications, both review and original articles, published in Google Scholar, PubMed, the available literature, as well as other commonly available sources. The search criteria included publications not older than 14 years, using the combination of the following keywords: “pain treatment”, “chronic pain”, “family physicians”, “pregnancy”, “children”, and “health services for the aged”. The total number of records was 243,527 items. We have included 30 works in the review, most of which are from the period 2016-2024. The subject matter of the works was the main criterion for selection based on which we made our choice. Excluded from the database of available articles were those whose topics differed significantly from those we covered and those published before 2010, with the exception of 2 published in 1959 and 2008.

DESCRIPTION OF THE STATE OF KNOWLEDGE

According to the definition of the International Association for the Study of Pain (IASP), pain is a subjective, negative experience that originates from stimuli currently or potentially damaging to body tissues. Its occurrence is also associated with the activation of the sympathetic nervous system and increased secretion of certain hormones. According to the recommendations of the IASP, patients with chronic pain should be treated in an interdisciplinary manner, considering not only pharmacological treatment methods but also psychological, rehabilitative, and other non-pharmacological approaches [4].

CLINICAL ASSESSMENT OF PATIENTS WITH CHRONIC PAIN

Proper assessment of pain intensity is a clinically significant factor determining the further management by the family physician at the initial therapeutic stage. In daily practice, scales are the most commonly used and readily available means of subjective assessment of symptom intensity by the patient. In addition to scales, it is equally important to obtain information from the patient regarding the pain location, potential causes, radiation, duration, character, aggravating or alleviating factors, response to medications, and observation of the patient’s behaviour [5-7].

VISUAL ANALOGUE SCALE

The visual analogue scale (VAS) is one of the most commonly used methods for pain assessment in practice (Fig. 1). It consists of a 10 cm line. The patient’s task is to indicate the intensity of pain from 0, which is defined as no pain at all, to 10, which represents the most severe imaginable pain. Sometimes, modified scales containing facial drawings or accompanied by verbal pain descriptions are also used. The main drawback of the visual analogue scale is that some patients (about 10-25%) are unable to select the appropriate position on the line, it also creates difficulties among patients with visual impairments [8] and is not suitable for use among patients under 6 years of age [9]. However, its significant advantage is the reliability of the obtained results [6].

NUMERICAL RATING SCALE

The scale consists of 10 levels, where 0 indicates no pain, and 10 the most severe imaginable pain (Fig. 2). The characteristics of numerical scales include ease of understanding and result repeatability, which makes it currently recommended for assessing both chronic and acute pain. The use of the numerical rating scale (NRS) is not recommended for children under 9 years of age [8].

VERBAL RATING SCALE

The verbal rating scale (VRS) allows for a descriptive assessment of pain, with each digit assigned a specific degree of severity of the complaint. The most commonly used is a 5-point Likert psychometric scale (Fig. 3). Its advantage is the possibility of use among children, although it requires age-appropriate modification [8]. However, a variable interpretation of the assigned descriptors by patients can be considered a drawback of the scale [5].

PAEDIATRIC PAIN ASSESSMENT SCALES

One of the methods used to determine pain intensity among the youngest population, newborns, infants, and preemies is the Modified Infant Pain Scale/Neonatal Infant Pain Scale (MIPS/NIPS). This is a behavioural scale assessing facial expression, breathing, limb movements, and behaviour. A score of 0 to 2 points indicates no pain or mild pain that does not require intervention, 3 to 4 points indicates mild to moderate pain, and > 4 points indicates severe pain. For older children below the age of 3 years, a behavioural scale assessing facial expression, leg position, general activity, crying, and ease of comforting (FLACC: face, legs, activity, cry, and consolability scale) is used. In the age range between 3 and 12 years, the Oucher scale is used, developed based on specific facial photographs carefully selected through years of research (separate scales for each race), as well as a simple finger scale (Finger Span Scale). For children between 6 and 8 years old, the Wong-Baker scale, created based on facial drawings (Fig. 4), is applied. Among school-aged children and adolescents, visual and numerical scales can be used, such as the visual analogue scale [9, 10].

THE IMPACT OF CHRONIC PAIN ON CENTRAL NERVOUS SYSTEM FUNCTION

Chronic pain has been shown to affect the structure and function of the brain, which can manifest as changes in behaviour, emotional, psychological, cognitive functions, and even abnormalities in cerebral blood flow and a decrease in the number of neurons [11]. The most significant disorders in the structure and functioning of the nervous system caused by pain are briefly discussed below.

CHANGES IN CENTRAL NERVOUS SYSTEM STRUCTURES

Modern research techniques have shown that chronic pain leads to reduced blood flow in the thalamus and basal ganglia. There is also a reduction in nerve tissue density in the brain cortex responsible for pain perception. It is estimated that this reduction progresses at a rate of 0.5% per year, which may be associated with cognitive dysfunction [12].

COGNITIVE FUNCTION DISORDERS

Among patients experiencing chronic pain in the studied group, up to 80% of them had problems related to memory and attention concentration disorders. They often experienced sleep disturbances, difficulties falling asleep, and the inability to maintain continuous sleep [13]. Sleep deprivation itself negatively affects the functioning of the nervous system, causing hormonal and metabolic disturbances, among others.

BEHAVIOURAL DISORDERS

Changes in the behaviour of individuals experiencing chronic pain have been and still are the subject of many studies, but the basis for conducting them was first introduced by Engel in 1959 with the concept of “pain personality” [14]. The most frequently occurring symptoms in the behavioural picture of pain include a painful posture, a suffering facial expression, and vocalisation (groaning, moaning) [15].

EMOTIONAL SPHERE DISORDERS

The connection between chronic pain and mental health, especially the emotional system, has long been known in the literature. It is worth noting that the patient’s mental state significantly affects their pain tolerance. At the same stimulus intensity, suffering and tolerance may vary depending on the mental state. According to estimates, depression is the most common reaction to chronic pain, affecting up to 70% of patients, and depressive traits may affect an even larger group [2]. Therefore, it is the role of the family doctor to pay attention to whether the patient shows depressive traits, so that treatment can be started as soon as possible and its further development prevented.

TREATMENT

According to IASP recommendations, patients with chronic pain should be treated in an interdisciplinary manner, considering not only pharmacological treatment methods but also rehabilitation programs, psychotherapy, neuromodulation, and others [4]. In the following part of the article, we briefly described the topics we selected in the subsections Pharmacological Methods and Non-Pharmacological Methods.

PHARMACOLOGICAL METHODS

The standard principle of pharmacological treatment for chronic pain is the use of the so-called 3-step analgesic ladder. According to this scheme, analgesic treatment should start with the use of non-opioid analgesics, which include nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol, metamizole, and nefopam. In the next stage, if analgesic treatment is ineffective, a weak opioid is added, which may be replaced by a strong opioid in further treatment [16]. At each stage of the analgesic ladder, it is also worth considering adjunctive drugs, including co-analgesics and drugs counteracting the side effects of analgesics. In medical practice, it is quite common to encounter a situation where there is a discrepancy in the effectiveness and dose of analgesic drugs that produce a satisfactory effect in different patients. This is due, among other factors, to genetic differences that affect drug metabolism, the pathomechanism of pain, and comorbidities. It is important to remember this and regularly assess the effectiveness of our actions. Family doctors often see patients in their office for whom pharmacotherapy requires special caution – these are paediatric patients, pregnant and breastfeeding women, and geriatric patients. Below are briefly discussed the most important differences in management in the above populations.

TREATING PAIN IN THE PAEDIATRIC POPULATION

Chronic pain experienced during childhood can have profound and enduring consequences, impacting a child’s academic, social, and physical growth, as well as their mental well-being. The limited research on paediatric chronic pain may indicate a broader issue of underrecognition and awareness surrounding this issue [17]. In this age group, especially in infants and young children, there are significant differences in pharmacokinetics due to factors such as a higher proportion of water to fat tissue, slower drug metabolism by the kidneys, and a more permeable blood-brain barrier compared to adults [18]. Pharmacological treatments commonly used in this context include analgesics such as acetaminophen and NSAIDs, gabapentinoids, clonidine, tricyclic antidepressants, and serotonin-norepinephrine reuptake inhibitors (SNRIs), where appropriate. Another emerging adjunctive therapy that warrants consideration as a potential opioid-sparing agent is cannabidiol (CBD), a nonpsychoactive cannabinoid found in cannabis. Tetrahydrocannabinol (THC), on the other hand, is responsible for the hallucinogenic effects associated with cannabis. Further research is required to assess the effectiveness and side effect profile of CBD in the management of chronic pain, as well as to clarify its associated risks and side effects [2]. In the management of chronic pain, opioids are generally limited due to their analgesic benefits being frequently outweighed by long-term adverse effects such as constipation, nausea, vomiting, and sedation. Moreover, there is a risk of developing tolerance, dependence, opioid-induced hyperalgesia, and addiction over time [19]. If intramuscular or subcutaneous injections are necessary, efforts should be made to reduce pain, for example, by using creams with local anaesthetics or non-pharmacological methods such as cuddling, explaining, and calming. Pharmacotherapy for pain should always be accompanied by all other treatment methods such as psychological support, rehabilitation, school attendance, participation in social life, sports activities adapted to capabilities, and proper sleep hygiene [20].

TREATMENT OF PAIN IN PREGNANT AND BREASTFEEDING WOMEN

Throughout pregnancy and breastfeeding, the first-line approach is the use of non-pharmacological methods. Pharmacotherapy for pregnant patients is challenging because it carries a higher risk of side effects and has more contraindications than in other stages of life. Before starting analgesic treatment, the different metabolism of drugs in the mother’s and foetus’s body, as well as their passage through the placenta, should be taken into account. The Polish Gynaecological Society, in its recommendations regarding pain management in gynaecology and obstetrics, recommends the use of analgesic drugs classified as category B or category C in terms of safety for use during pregnancy according to FDA criteria, but only in exceptional and justified clinical cases [21]. Paracetamol is the drug of choice for pain treatment in any stage of pregnancy, regardless of its duration and other additional systemic burdens on the pregnant woman. At standard doses (1-4 g/day), it has a high safety profile, does not exhibit teratogenic effects, and does not increase the risk of miscarriage, preterm birth, or foetal death [21]. The use of NSAIDs during the second trimester for a few days does not seem to present a significant risk. However, prolonged use in the late second trimester may lead to conditions like oligohydramnios and constriction of the ductus arteriosus, similar to effects observed with NSAID use in the third trimester [22]. In situations where the use of strong opioids is necessary, morphine, which is highly hydrophilic, may be considered. During breastfeeding, paracetamol or ibuprofen can be administered, with only 1% of ibuprofen passing into breast milk [18].

TREATMENT OF PAIN IN THE GERIATRIC POPULATION

Elderly individuals (> 65 years old) are more frequently exposed to chronic pain than the general population due to the increasing number of accompanying conditions with age, such as musculoskeletal disorders, pain caused by cancer, as well as cancer treatment, advanced stages of many chronic diseases, or neuropathies [23]. The presence of multiple comorbidities often leads patients to take several different medications, increasing the risk of adverse pharmacological effects in attempts to alleviate pain due to unfavourable interactions [18]. All elderly patients with chronic pain should undergo comprehensive assessment of geriatric pain to ensure that treatment provides them with the greatest benefits. A multimodal approach is recommended, including non-pharmacological methods of pain relief [23]. It is also recommended that combinations of several drugs be used instead of a single drug at higher doses, due to greater analgesic efficacy with lower toxicity [24]. In cases of mild pain, non-opioid analgesics should be the basis of pharmacotherapy. Paracetamol is the preferred analgesic in this patient group due to its favourable safety profile, along with metamizole. They provide analgesic and antipyretic effects but do not exhibit anti-inflammatory activity. Metamizole also has spasmolytic effects, so it is recommended for colicky and visceral pain. If possible, the use of NSAIDs should be limited because they may cause gastrointestinal bleeding, kidney failure, worse blood pressure control, and other adverse effects. When NSAIDs are necessary in therapy, it should be remembered that in patients at increased risk of gastrointestinal and renal complications, selective cyclooxygenase 1 (COX-1) inhibitors with long half-lives (e.g. indomethacin) should not be used, and in individuals with risk factors for acute vascular events, individual risk assessment for the use of selective cyclooxygenase 2 (COX-2) inhibitors is recommended. Topical NSAIDs are an alternative to oral forms; they are usually well-tolerated by patients and should be considered especially in patients with localised pain [18, 23]. Opioid administration should be considered when pain persists despite other treatment methods or when serious functional impairments persist despite treatment. If the decision is made to treat with opioids, strict monitoring should be conducted approximately every 2 weeks at the beginning of treatment and during dose escalation to ensure treatment goals are being achieved. If not, the drug dose should be gradually reduced and discontinued [23]. In the elderly patient group, there is often fear of using opioids. Opioidophobia most commonly arises from lack of knowledge, so it is important to find time to talk to the patient, explain the nature of the disease and treatment, and to encourage patient cooperation.

NON-PHARMACOLOGICAL METHODS

PSYCHOLOGICAL TREATMENT

Patients suffering from chronic pain often experience significant psychological problems, such as depression or anxiety disorders [25]. Psychological treatment methods include patient psychoeducation, cognitive therapy, behavioural therapy, relaxation techniques, and stress resilience enhancement. The above methods aim to change the patient’s perception of pain, build a sense of control over pain and their own life, practice effective pain coping strategies, return to work and an active lifestyle, and reduce the amount of analgesics taken.

REHABILITATION

Implementing appropriate rehabilitation protocols significantly influences the reduction of pain intensity, improvement of mobility, and functionality in patients. Well-adapted rehabilitation aims to prevent injuries and pain exacerbation. We can distinguish between active therapy, during which patients perform dynamic movements or static muscle contractions, with or without additional external load, and passive procedures, including manual therapy or massage [26]. Physical modalities are often additionally used, including transcutaneous electrical nerve stimulation (TENS), heat/cold therapy, traction, laser therapy, ultrasound, shortwave diathermy, and interferential therapy. Patients should be motivated to perform exercises tailored to them, because improving physical activity also helps improve quality of life.

NEUROMODULATION

Neuromodulation is an evolving method for pain treatment, encompassing various non-invasive or invasive electrical therapies. They are used to activate mechanisms inhibiting pain generation and perception [27]. One of the most popular neuromodulation techniques is transcutaneous electrical nerve stimulation (TENS). TENS, due to its positive characteristics such as relatively low cost, user-friendliness, easy accessibility, few side effects, and observed effects after application, is often used by patients. However, there is not yet sufficient research to definitively assess the effectiveness of this technique [28]. Other commonly used neuromodulation methods in practice include direct stimulation of peripheral nerves and spinal cord dorsal column stimulation. However, these are invasive methods associated with greater risk of complications.

THERMOCOAGULATION

One of the modern methods of pain treatment is thermocoagulation utilising the action of electricity, which can conduct high-frequency radio waves. This leads to the destruction of nerve structures by an electrode generating a temperature above 45°C. Positive results of thermocoagulation are achieved in patients with trigeminal neuralgia, cluster headaches, cancer pain, and in patients where degenerative changes are the origin of pain symptoms [29]. Unfortunately, the availability and cost of such a procedure mean that most patients are unable to benefit from this method.

ACUPUNCTURE

Acupuncture is a therapeutic method particularly developed in Far Eastern countries. This type of treatment is increasingly used as complementary pain therapy. Patients tolerate acupuncture well, and it is associated with a low risk of serious adverse effects. The variability of acupuncture’s therapeutic effects can be influenced by many factors, including needling technique, number of needles used, duration of needle retention, specificity of acupuncture point, number of treatments, and various subjective (psychological) factors [30]. Acupuncture appears to be an effective therapy in the management of acute postoperative pain, but additional basic and clinical research is needed to adequately characterise the mechanisms of acupuncture and clinical effects on pain [2].

CONCLUSIONS

Family doctors encounter patients suffering from accompanying pain almost every day in their offices. Pain often significantly impacts quality of life, hinders social functioning, and contributes to isolation. Properly tailored therapeutic interventions are crucial because inadequate pain management negatively affects the functioning of the nervous system. This often manifests as changes in behaviour, and emotional and psychological disturbances. Modern research techniques have shown that chronic pain leads to reduced blood flow in the thalamus and basal ganglia. There is also a reduction in nerve tissue density in the brain cortex responsible for pain perception, which may be associated with cognitive dysfunction. According to estimates, problems related to memory and attention concentration occur in up to 80% of patients suffering from pain. Depression affects as many as 70% of these patients, and depressive traits may impact an even larger group. The negative effects are visible in every sphere of the patient’s life, making it essential to have skills in proper pain intensity assessment and knowledge of current therapeutic options, with an emphasis on an interdisciplinary approach that combines pharmacological and non-pharmacological methods, such as rehabilitation. The standard principle of pharmacological treatment for chronic pain is the use of the so-called 3-step analgesic ladder. Special patient groups include pregnant and breastfeeding women, children, and the elderly. When introducing pharmacological treatment, caution must be exercised to consider possible interactions or adverse effects. If the treatment methods used are insufficient, the patient should be promptly referred to a pain management clinic.

Disclosures

This research received no external funding.
Institutional review board statement: Not applicable.
The authors declare no conflict of interest.

References