Everything you need to know about pain management: approaches, types, and advances

Pain, a universal and complex experience, represents a major public health challenge worldwide. In France, the National Institute of Health and Medical Research (Inserm) estimates that it accounts for two-thirds of all medical consultations. Even more alarming, no fewer than 12 million French people suffer from so-called "chronic" pain—that is, pain that persists for more than three months, responds poorly to conventional treatments, and significantly affects patients' quality of life, both personally and professionally. This condition becomes more common with age and is more prevalent in women.

Far from being a mere symptom, chronic pain becomes a disease in its own right when it persists over time, thereby losing its function as a warning signal. Faced with this reality, researchers and healthcare professionals are making considerable efforts to better understand its mechanisms and, above all, to improve its management. This article aims to explore in depth the various aspects of pain treatment, from its fundamental understanding to the most innovative therapeutic strategies.

Understanding pain: an essential step toward better treatment

To understand pain treatment, it is essential to understand its nature. The International Association for the Study of Pain (IASP) defines pain as "an unpleasant sensory and emotional experience associated with, or resembling, that associated with actual or potential tissue damage." This definition emphasizes its subjective and multidimensional nature, involving both physical sensations and emotions. There is not just one form of pain, but rather several types, each with distinct characteristics, although there may be complex overlaps in some patients. Sources primarily identify three categories of pain, classified according to their nature and duration: Nociceptive pain: This is directly related to the stimulation of nociceptors, specialized receptors activated by potentially damaging stimuli. These stimuli can include a blow, joint inflammation, or excessive heat. The information captured by nociceptors is transmitted via specific nerve pathways to the brain, where it is interpreted, particularly in the cerebral cortex. This type of pain is often described as a useful warning signal for determining the cause. Neuropathic pain: Unlike nociceptive pain, this type of pain is caused by damage to nerve fibers or the central nervous system itself. It can occur, for example, during shingles (reactivation of the chickenpox virus), diabetes, or following an amputation. It is often described as burning, tingling, electric shock, numbness, or stabbing sensations. Even the slightest touch can cause unbearable pain, a phenomenon called allodynia or hyperalgesia, characteristic of this type of pain. It is sometimes misunderstood by patients and caregivers, and can even be felt far from the nerve lesion itself. Nociceptive pain: This pain is sometimes similar to neuropathic pain, but it is often generalized throughout the body and is not associated with visible damage to nerve fibers. It is thought to result from a dysfunction of the pain detection and control system itself, leading to an exaggeration of the nerve signal and/or an overinterpretation of this signal by the brain. Fibromyalgia, characterized by widespread and persistent pain, sensitivity to pressure, intense fatigue, and sleep disturbances, is an example. There are also genuine pains without visible lesions, often referred to as dysfunctional pain.

Pain is a multidimensional syndrome, and its mechanisms are complex. The brain plays a central role, as it is the brain that "controls" pain. Pain has three well-defined components within the brain:

• The sensory-discriminative component: This allows us to pinpoint the location of pain and assess its intensity. A dysfunction can lead to the generalization or spread of localized pain.
• The affective-emotional component: This determines the emotion associated with the pain. Excessive emotional intensity may warrant an investigation into an underlying anxiety or depressive disorder.
• The cognitive-behavioral component: Painful information is associated with anxiety and is stored in memory, influencing future behavior. An overly strong component can lead to kinesiophobia (fear of movement).

The intensity of pain can be influenced by the context (family, work, social), emotions, and levels of anxiety and depression. The memory of past painful experiences can also intensify the perception of pain. It is important to note that there is not always a direct link between the severity of an injury and the intensity of the pain felt. Test results may be normal despite intense pain, either because the lesion is invisible (too small, early stage), or because the pain is caused by multiple factors.

Pain assessment: the key to personalized care

Accurate pain assessment is a fundamental prerequisite for any effective care. The patient is at the center of this assessment, because no one is better positioned than they are to describe their pain, quantify its intensity, and determine where and when it occurs. They are also the only ones who can judge the effectiveness of treatments and the relief they provide.

Unlike many medical conditions, there is no radiological or biological test that can objectively measure pain; there is no "pain marker." Assessment therefore relies on the patient's ability to communicate and describe their experience. For individuals able to express themselves, healthcare professionals use several self-assessment scales: The Visual Analog Scale (VAS): This is presented in the form of a ruler. The patient places a marker on a line ranging from "No pain" to "As bad as I can stand." The healthcare professional reads the corresponding value on a scale of 0 to 10. The Numerical Rating Scale (NRS): Simpler, it asks the patient to rate their pain from 0 (no pain) to 10 (as bad as I can stand). It is widely used because it does not require any additional tools.

These scales (VAS, NRS, SVS) provide information on the overall intensity of pain, but do not provide information on the causes or mechanisms of the pain. In cases where there is a discrepancy between what the patient expresses and what the caregiver observes, the professional must believe the patient and adjust the scale used, seeking to understand the difference. The challenge of assessment becomes more complex when the patient is unable to express themselves verbally, such as young children, elderly people with reduced autonomy, or people with multiple disabilities. In these situations, any change in behavior can be a sign of pain. Caregivers and family members must be particularly attentive to physical and behavioral cues, such as moaning, grimacing, stiffness, agitation, protective gestures, withdrawal, refusal to eat, sleep disturbances, or irritability. Specific observation grids have been developed for these populations, allowing them to identify these cues and assess the intensity of the pain. Among them are:

• For children: the EDIN, HEDEN, and EVENDOL scales; the facial scale; the vertical EVA; the San Salvadour grid (or DESS); and the modified FLACC scale (from birth to 18 years). There is also a pediatric DN4 scale for neuropathic pain.
• For elderly and/or non-verbal individuals: the Doloplus2® scale, the Algoplus® scale, and the Behavioral Scale for Elderly People (ECPA).
• For adolescents and adults with multiple disabilities: the EDAAP (Evaluation of Pain Expression in Adolescents or Adults with Multiple Disabilities), the EDD (Evaluation of Pain Expression in People with Communication Difficulties), the GED-DI (Pain Assessment Grid – Intellectual Disability), and the ESDDA (Simplified Pain Assessment Scale for People with Communication Difficulties and Autism Spectrum Disorder).

Communication is essential. Healthcare professionals must consistently inform patients about the treatment to be administered and the pain management methods used. Pain caused by medical care is predictable and must be consistently prevented and treated, as it can lead to anxiety, exhaustion, and even refusal of care.

Drug treatments for pain management

The pharmacological management of pain (see our article on Nefopam) is tailored to its cause, intensity, duration, and location. The practitioner selects treatment modalities based on the type of pain (chronic, postoperative, care-related, migraine, etc.), following best practice guidelines. The goal is to counteract the pain mechanism and treat it according to its specific characteristics, prioritizing well-tolerated medications and taking the patient’s medical history into account.

Conventional analgesics are the first-line treatment for nociceptive pain, whether acute or chronic. They belong to different pharmacological classes, ranging from the mildest to the most potent:

• Acetaminophen.
• Certain nonsteroidal anti-inflammatory drugs (NSAIDs).
• Opioids, which can be mild or strong.

Opioids are a major class of analgesics. They work by mimicking the action of endogenous opioids (endomorphin or endorphin) produced naturally by the body, primarily in the central (brain and spinal cord) and peripheral nervous systems. We distinguish between:

• Weak opioids (Step 2): codeine, dihydrocodeine, tramadol, opium. They are prescribed for moderate nociceptive pain, either as a first-line treatment or when Step 1 analgesics have failed.
• Strong opioids (Step 3):: alfentanil, fentanyl, hydromorphone, morphine, oxycodone, pethidine, sufentanil, tapentadol. Morphine is the first-line strong opioid for cancer pain. These opioids are recommended for intense, acute, subacute (surgery, emergencies), persistent, or recurrent nociceptive pain (cancer), and in certain specific situations when first-line treatments have failed. Titration is an essential method for rapidly adjusting the dosage of an opioid, often performed in the recovery room for postoperative pain. Opioids can be administered via various routes: intravenous, subcutaneous, or oral. For chronic pain, a maintenance (daily) regimen is necessary, supplemented by immediate-release (inter-dose) medications for transient pain episodes. Opioids, like all medications, can cause side effects, the most common being constipation (almost inevitable with chronic use and requiring preventative measures starting with the first dose) and drowsiness (which usually decreases after a few days of titration). Other effects such as nausea, vomiting, sweating, nightmares, impaired attention, concentration, and memory, hallucinations, and myoclonus (involuntary muscle twitching) may occur. In cases of persistent side effects or ineffectiveness, opioid rotation is an option. It is important to emphasize that opioids are not always indicated for all types of pain. They are of little or no effectiveness for neuropathic pain and should not be used for primary headaches (including migraines) or nocipathic pain (fibromyalgia). The fear of morphine addiction is a misconception; its use post-operatively or for its analgesic effect does not lead to drug addiction or dependence. Discontinuation of strong opioid treatment should always be done under medical supervision, with a gradual reduction in dosage. In addition to conventional analgesics, doctors may use other medications that have an analgesic effect even if that is not their primary purpose, particularly for chronic neuropathic pain. This is the case with certain antidepressants or antiepileptics, which act specifically on the mechanisms of this pain. It is important to note that prescribing these medications in this context does not imply that the patient is considered depressed or epileptic. Unfortunately, they are effective in only one out of every two patients. Local pharmacological treatments are also available for chronic pain. These include, for example, lidocaine patches (a local anesthetic) or capsaicin patches. Botulinum toxin injections can also be used for certain localized neuropathic pains, with an effect lasting several months. Combining medications with complementary actions can maximize effectiveness while limiting side effects (e.g., acetaminophen or an NSAID with an opioid). It is generally not recommended to combine medications from the same class to avoid overdoses. Regarding the route of administration, the common belief that injection is more effective than oral administration is often false; the oral route is often comparable in effectiveness and avoids the painful procedure of injection. In cases of persistent pain despite treatment, several possibilities exist: the pain mechanism no longer corresponds to the drug’s mode of action, the dose, route, or frequency of administration is inadequate, or there is variability in individual response. Medical monitoring is essential to adjust the treatment. It is recommended to take analgesics before the pain becomes too severe, as persistent acute pain can perpetuate itself and become chronic. Analgesics do not interfere with examinations, and it is even recommended to treat pain as a priority to allow examinations to be performed under optimal conditions. Non-pharmacological approaches: an essential dimension. Beyond medication, numerous non-pharmacological techniques play a key role in pain management, particularly for chronic pain. They are complementary to drug-based approaches and can be very useful. In some cases, such as chronic pain, medication may play only a very limited role (less than 30%) in overall management. These approaches fall into several categories:
  1. Physical approaches:
     • Massage therapy.
     • Physiotherapy, including the application of heat, cold, or electrical current.
     • Balneotherapy.
     • Supportive devices (corset, foam collar, strapping).
     • Postural and movement education.
     • Rehabilitation through exercise and functional restoration of the spine, particularly for chronic lower back pain. Strict bed rest is no longer considered an effective treatment for chronic lower back pain.
  2. Electrical or magnetic stimulation:
     • Transcutaneous electrical nerve stimulation (TENS): Electrodes temporarily attached to the skin deliver a low-intensity current to relieve pain. It works by "blocking" the transmission of pain signals in the nervous system and/or by stimulating the production of endogenous analgesics (substances naturally produced by the body). A trial session is required to adjust the settings, and the device is used regularly by the patient.
     • Spinal cord electrical stimulation: This more invasive procedure involves implanting electrodes in the spinal column to block the transmission of pain signals.
     • Repetitive transcranial magnetic stimulation (rTMS): A very promising treatment, it involves applying a powerful magnetic current to the scalp to modify the electrical activity of brain regions involved in pain control. Recent studies have explored its use to identify patients who could benefit from it, particularly for neuropathic pain.
  3. Mind-body methods: These methods address the person’s physical and psychological dimensions, helping them to tap into their own resources. They counteract situations of muscular and emotional tension linked to pain and stress, and can break the vicious cycle of pain-tension-stress. They are complementary to medication and include: relaxation, hypnosis (or hypnoanalgesia) for pain relief, sophrology, and meditation. These techniques often require training to enable independent use (self-relaxation, self-hypnosis). When practiced by specifically trained professionals, they are ethical and safe. They can be effective for a wide range of situations and types of pain, with varying degrees of effectiveness.

Non-pharmacological management is particularly relevant for specific populations:

• For children, methods such as offering sugar water or breastfeeding for newborns, distraction, and hypnoanalgesia are essential for preventing pain associated with medical care. Learning mind-body techniques (relaxation, biofeedback, hypnosis) is an effective long-term treatment for migraines in children.
• For elderly and multi-disabled individuals who are unable to communicate, special precautions are necessary before any painful procedure. In addition to local anesthetics and MEOPA (an equimolar mixture of oxygen and nitrous oxide), non-pharmacological methods—such as choosing the right location, having a loved one present, using toys or familiar objects, playing music, and simply talking—are essential.

The Placebo Effect and the Therapeutic Relationship

The placebo effect is a fascinating and increasingly studied aspect of pain management. A placebo is a substance (or any other intervention, such as surgery or the therapist’s actions) that appears to treat a health problem, even though it has no proven pharmacological or specific effect on that problem. The placebo effect, meanwhile, refers to the non-specific benefit that is added to the scientifically proven efficacy of any drug or therapeutic procedure, thereby increasing the “total” efficacy of the treatment.

How does this effect work? Several mechanisms contribute to its effectiveness:

• The relationship of trust: Establishing a bond of trust between the healthcare provider (the one who prescribes or administers treatment) and the patient (the one who receives it) is essential.
• The patient's expectations and beliefs: The higher the patient's expectations and the stronger their belief in the treatment, the greater the treatment's effectiveness (and therefore the placebo effect) will be.
• The healthcare provider's conviction: A physician's enthusiasm and conviction regarding a treatment can also enhance this effect.
• Cognitive and emotional mechanisms: Clear explanations, reassurance, and a supportive attitude from the healthcare provider contribute not only to trust but also to a reduction in anxiety, which is a major factor in the placebo effect.
• Neurobiological Mechanisms: The pain-relieving effect of a placebo is underpinned by neurobiological mechanisms of the same nature as the specific effect of an analgesic, notably involving the activation of the body's endogenous opioid systems.

The placebo effect is not limited to pain medications; it contributes to the effectiveness of all medications. From an ethical standpoint, in the context of clinical trials, the use of a placebo must be accompanied by the option to prescribe rescue pain medication if the pain level reaches a predefined threshold.

To maximize the effectiveness of a treatment, it is beneficial to harness the placebo effect. This involves building a strong relationship of trust between patients and healthcare providers, known as the therapeutic alliance. This alliance is one of the key components of successful treatment, along with the accuracy of the information provided and the resulting trust. When patients understand and accept how the medication works, they expect to experience noticeable relief, which enhances overall effectiveness.

Psychology and Pain: A Complex Interaction

The question of whether pain is "all in your head" is a common one. According to the IASP definition, pain is an unpleasant experience that is both sensory and emotional. This means that it is experienced simultaneously on both a physical and psychological level, regardless of its origin. Therefore, there is no physical pain without a psychological counterpart, and conversely, no psychological disorder without a physical correlation. Sometimes, the pain felt in the body can be the unconscious expression of an underlying psychological difficulty (trauma, grief, separation). However, it is essential to emphasize that treating chronic pain exclusively with psychotherapy is pointless. On the contrary, a multidisciplinary approach is indispensable, and the psychologist makes a valuable contribution to the diagnosis. The psychological state strongly influences the perception of pain. Pain is more difficult to bear in the presence of anxiety or depression, which are aggravating factors that must be identified and addressed. Chronic pain can lead to depressive disorders through exhaustion, and conversely, a depressive illness can manifest primarily as pain. The symptoms of depression and chronic pain are often similar: fatigue, nervousness, loss of appetite, sleep disturbances, and loss of pleasure. Chronic anxiety, especially in the form of panic attacks, also manifests with various painful physical symptoms. Post-traumatic stress can develop into intractable pain requiring specific and comprehensive management. The patient’s lifestyle can also influence pain. It is often a vicious cycle: lack of sleep worsens pain, and pain disrupts sleep; poor diet can influence the pain experience; overactivity may seem to distract from the pain but exhausts the body and intensifies it. Comprehensive management must therefore address lifestyle and consider lifestyle adjustments. Unfortunately, it is common for pain whose cause is not immediately identified to be labeled "psychosomatic." Sources emphasize that this term is a "catch-all" word, often used as a default diagnosis—unnecessary and even stigmatizing. The absence of an organic explanation in no way means that the patient is "crazy"; health sciences are not absolute knowledge, and a complex situation can be difficult to grasp in all its aspects. The goal is rather to adopt a therapeutic approach that integrates the dialogue between body and mind, which is essential in pain management.

When pain becomes unbearable and prevents one from living, it is essential to seek help. A multidisciplinary team can help you rethink your daily activities and determine what can be adapted, maintained, or given up. The experience of pain permanently alters self-perception, abilities, and relationships with those around them; life will never be “the same as before,” but this experience can be a life lesson that changes one’s relationship with existence. In extreme cases where the pain is unbearable and leads to suicidal thoughts, it is vital to reach out to a trusted person or a healthcare professional to seek solutions.

Specialized and multidisciplinary care: chronic pain management structures (CPMS)

Faced with pain that persists for a long time, is complex, and for which the patient feels misunderstood, the attending physician remains the primary contact. After several consultations and attempts to find effective solutions, they may refer the patient to a specialist. However, in certain complex situations, referral to a Specialized Chronic Pain Structure (SDC) will be proposed.

SDCs are healthcare facilities identified and specialized in the management of chronic pain. They meet specific specifications and are certified by the Regional Health Agencies (ARS), with a five-year renewal of this certification. They bring together healthcare professionals from different disciplines (doctors, nurses, psychologists, etc.) who are experts in pain assessment and treatment.

To obtain an appointment in SDC, it is generally necessary to discuss it beforehand with your general practitioner or a specialist, who will assess the relevance of this referral. The patient will often have to fill out a referral questionnaire and return it with an introductory letter from their doctor. The addresses of the SDCs are available via a directory of the Ministry of Health or from the ARS.

The operation of a Pain Center (SDC) is based on individualized care. An initial assessment, which may extend over several long consultations, is carried out. This assessment is fundamental to carrying out an exhaustive bio-psycho-social assessment, which takes into account the biological, psychological and social dimensions of pain. This assessment then makes it possible to develop a personalized therapeutic project, discussed with the patient.

This project may include various treatment modalities:

• Drug therapies.
• Non-pharmacological approaches (hypnosis, relaxation, transcutaneous neurostimulation, etc.).
• Psychological support.
• Specific examinations and technical procedures.
• Sometimes, a short hospital stay or referral to another, more specialized facility is required.

The meeting with professionals such as a psychologist, psychiatrist, or social worker, which may be surprising at first, is justified by the fact that chronic pain has repercussions on all aspects of daily life. It can lead to emotional distress, socio-professional and financial difficulties, and an impact on quality of life and relationships, which in turn amplify the pain. The objective is to take into account all these consequences and implement solutions to mitigate them. The attending physician remains a key player, regularly informed of the patient's progress.

In this pathway, the patient is actively informed of the modalities of the therapeutic project so that they can remain an active participant in their care. They are encouraged to develop behaviors adapted to daily life, to understand their illness and its treatments, to observe their own reactions to better manage crises, and to respect the prescriptions and advice of professionals. Acceptance of help and adaptation of physical, professional, family, and social activities are essential to improve quality of life.

For information, patients are encouraged to turn to reliable resources: healthcare professionals, approved associations (such as France Assos Santé), and reference websites such as the Société Française d'Étude et de Traitement de la Douleur (SFETD), the Centre National Ressources Douleur (CNRD), or the Haute Autorité de Santé (HAS). Patient therapeutic education (PTE) is also a major lever, with validated and free programs that help patients become more autonomous in managing their pain.

Patient rights and advances in research

Pain management is not only a medical issue but also a fundamental patient right, enshrined in French law. Article L.1110-5 of the Public Health Code stipulates that "Every person has the right, given their state of health and the urgency of the interventions it requires, to receive, throughout the territory, the most appropriate treatments and care and to benefit from therapies whose effectiveness is recognized and which guarantee the best health safety and the best possible relief of suffering in light of established medical knowledge." More specific laws, such as the 1999 law on access to palliative care and those of 2005 and 2016 on patient rights and end-of-life care, reinforce this right.

Healthcare professionals also have legal obligations regarding pain:

• The nurse's objective is to "participate in the prevention, evaluation, and relief of pain and physical and mental distress of individuals."
• The physician "must strive to alleviate the patient's suffering by means appropriate to their condition and assist them morally."

Patient rights also include therapeutic education. The 2009 Hôpital Santé Territoires law and the 2015 decree frame the TPE programs, aimed at making the patient more autonomous by facilitating their adherence to treatments and improving their quality of life. Access to these programs is voluntary, free and without charge.

In parallel with this legal framework, pain research is particularly active and has progressed considerably in recent years. These advances are essential to refine treatments and offer new perspectives to patients.

• Genetic variations: It is now known that genetic variations explain the difference in response from one patient to another for the same analgesic, as well as the occurrence of adverse effects. For example, variations in the COMT gene, involved in dopamine secretion, may be linked to an increased risk of pain becoming chronic.
• New players in pain: Scientists have identified new molecules and cells involved in the mechanisms of pain. The immune system, metabolic disorders, and the intestinal microbiota may also play a role in the chronification of pain.
• Cerebral Imaging: Advances in medical imaging have enabled the visualization, and even quantification, of pain, leading to a better understanding of the structural and functional changes in the brain areas that process pain information in cases of chronic pain.
• Understanding the types of pain: Knowledge of the different types of pain has become more refined, with each type being transmitted by distinct nerve pathways.
• Fundamental discoveries: In 2021, the Nobel Prize in Medicine rewarded the discovery of TRP and PIEZO channels, involved respectively in thermal and mechanical nociceptors, opening new avenues for analgesic research.
• Promising proteins: Aziz Moqrich's team has discovered the TAFA4 protein, showing in rodents a powerful action against inflammatory, neuropathic and post-operative pain, with a longer duration of action than conventional painkillers such as opioids. The protein is also thought to have a reparative effect on damaged tissue, which could prevent chronic pain. A Phase I clinical trial in humans is expected shortly.
• Therapeutic targets: New therapeutic targets for chronic inflammatory pain are being identified.

Although significant progress has been made, intense research is still needed to improve the management of chronic and inflammatory pain, the mechanisms of which are complex and vary from patient to patient.

In conclusion, pain management is a constantly evolving field, requiring a holistic and multidisciplinary approach. Understanding pain in all its dimensions – sensory, emotional, cognitive, and behavioral – is the first step towards effective relief. The therapeutic arsenal today combines increasingly targeted drugs and various non-pharmacological approaches, all framed by a rigorous evaluation and a relationship of trust between the patient and their care team. Specialized chronic pain structures play an important role for complex cases, while basic research continues to pave the way for even more innovative treatments. The ultimate goal is to alleviate suffering and ensure that no one is left alone in the face of their pain.

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