The chronic pain It is the symptom of par excellence in medicine, and the most common cause of visiting the doctor. Traditionally pain has been considered as a specific sensation in the face of harmful stimulation.
Therefore, it would be the result of tissue damage or organic pathology, its intensity being proportional to the amount of the lesion. It would have an adaptive function by signaling the presence of an injury.
This approach has been simplistic: You can report little or no pain after an injury, not feel pain at the time of injury. In addition, in some injuries, it takes up to 9 hours before the onset of pain.
Not to mention the phantom limb pain, the very common presence of pain without any physical cause, the pain of "empathy", etc.
- 1 Chronic pain: in search of detectable evidence
- 2 types of pain
- 3 Explanatory factors of chronic pain
Chronic pain: in search of detectable evidence
In many cases of chronic pain there is no detectable evidence of tissue damage. In addition, pain is usually disproportionate to the severity of the injury, and can be maintained even after blocking the pain transmission pathways.
Instead, this one may disappear through hypnosis, suggestion or placebos. This indicates that the experience of pain, at least the chronic one, does not refer exclusively to the sensory aspects of the phenomenon, but is multidimensional in nature.
The pain has a multidimensional nature
These dimensions interact with each other, so that can influence each other:
- Sensory-discriminative dimension, whose function is to transmit harmful information by facilitating discrimination of the physical properties of the stimulus, spatial location, intensity, etc.
- Motivational-affective dimension, whose function is related to the characterization of pain as unpleasant and aversive. It facilitates the unpleasant emotional experience, which elicits escape responses, avoidance and protective behaviors. As well as emotions of anxiety and depression associated with pain.
- Cognitive-Evaluative Dimension, involved in the interpretation and assessment of pain. Its sensory characteristics and other factors such as attention aspects, previous experiences, sociocultural context, beliefs associated with pain, the level of perceived control, attributional processes on the cause, etc. are taken into account.
Types of pain
As for the types of pain, the acute and chronic can be distinguished fundamentally.
1. Acute pain
The acute pain refers to the case of a well-defined damage or injury from which the pain as a symptom (bone fracture, tooth break, etc.). It has a rapid onset and subsequent maintenance over a more or less extensive period until the cause disappears.
This associated with high levels of anxiety, proportional to the severity of the injury. The changes in the patient's physical and social environment due to pain are short-lived (less than six months) and after healing the repertoire of social behaviors is automatically restored, without requiring retraining.
2. Chronic pain
The chronic pain It starts as acute, because of an injury or injury, but persists after healing. It is not a symptom of a wound or other organic pathology. The duration is very long (more than six months).
It is usually associated at first with high levels of anxiety and then a high degree of depression.. Patients describe pain more in affective than sensory terms.
I know produce permanent changes in the physical and social environment that modify the habitual behavior of the patient and his relatives.
Medical procedures provide effective means of treating acute pain. However the chronic pain, the result of a complex interaction between psychological and biological variables, a multidisciplinary approach is required.
Explanatory factors of chronic pain
1. Learning factors
From the perspective of learning, if the physiological cause of pain lasts for several months, it is very likely that learning effects will occur and conditioning. Therefore, they can cause pain behaviors to persist once the physical causes have disappeared.
For this we can distinguish three mechanisms:
Direct positive reinforcement
Attention of the medical staff, family and social environment of the patient in the face of pain behaviors can become a source of reinforcement capable of maintaining such complaint behavior by itself.
Also, it is usual prescribe rest on a continuous basis and abandonment of work when pain begins to be felt. The administration of analgesics, compensation and financial subsidies, etc.
Thus,Patients with chronic pain are exposed to multiple sources of rewardseconomic Y social They can condition your symptoms and keep the disorder.
Both types of rewards are positively associated with more lost days of work, more disability in the domestic environment and more levels of depression. But differentially, patients with more social rewards have higher levels of pain and more nonspecific medical complaints.
If you pay attention to the patient for their pain behaviors, they respond congruently, they follow the expectations placed on them. In fact, you strengthen their beliefs about the truth of their pain.
The conclusion is that exposure to the two types of rewards explains a very significant amount of variance in the behavior of the patient with chronic pain that cannot be explained by biological variables.
Punishment and extinction of habitual patterns of patient behavior
After the appearance of the injury or illness, medical staff and family members express concern about any patient activity that involves physical work. Therefore, these behaviors are systematically punished, or not followed by positive reinforcement. In this way, its emission is reduced until it is extinguished.
This is a fundamental mechanism. In the acute phase of the problem, physical exercise or work is associated with pain, as well as all activities or situations in which episodes of pain have occurred.
Rest is followed by decreased pain and, therefore, is negatively reinforced. In fact, after the physical injury disappears the avoidance of any physical work is maintained.
They will also keep the ephobic vitation of the situations and activities associated with pain. Therefore, the avoidance not only of movement and activity, but also of social interactions and any stimulation associated with pain is the most prominent component of pain behaviors.
In addition, the issuance of complaints is followed by the avoidance of work., elimination of noise levels, anxious situations, stress and burdensome responsibilities.
Environmental contingencies in the behavior of the patient with chronic pain
The attention and request of the spouses towards complaints and pain behaviors of their partners increases the frequency of this type of behavior and the subjective intensity of pain that patients report.
When patients with chronic pain increase physical exercise rates, which they previously avoid, pain behaviors decrease.
Both data demonstrate that pain behaviors are partly under environmental contingencies. In the face of treatment, it is essential to deprogram some of the behavioral adaptations developed to cope with pain, especially removing passivity and increasing physical exercise.
The learning of the behaviors that are exhibited in the face of pain is mainly done through vicarious learning. Such is the importance of social modeling that has been seen experimentally that The exhibition to tolerant models (people who cope with their problems without complaining and in a measured way) versus intolerant (exaggerated complaints, signs of disability, etc.) cause the levels of pain tolerance and reports of pain perceived by experimental subjects to be modified.
In the case of chronic pain, it is common to find families whose members they have very similar pain problems, regardless of the organic causes.
Exposure, especially in childhood, to models that exhibit pain behaviors or hypochondriacal beliefs exaggerated or deviant is a learning source of behaviors that facilitate the subsequent development of abnormal pain behavior patterns. Thus, it is not surprising that conventional treatments can be ineffective when pain disorders occur.
2. Cognitive factors that affect chronic pain
In the experience of pain, the affective and cognitive-evaluative dimensions are also important. An important element in the chronic pain What can foster a pain sensitization process is the development of cognitive biases.
We can distinguish two types of bias:
- Interpretive bias. The subject evaluates pain and sensations linked to it as very negative, giving it more importance than they have.
- Attention bias. The previous evaluative bias results in attention bias: the subject pays selective attention to these types of sensations, the attention is constantly focused and focused on those areas and bodily sensations (attention hypervigilance).
- Therefore, it can cause a perceptual sensitization and lower the perceptual threshold. This implies that low intensity sensations are perceived as painful.
3. Vital events
It is frequent that In patients with chronic pain problems there is no biological cause that can explain the intensity of pain. But a high prevalence of chronic stress and traumatic life events (physical and sexual abuse) can be found.
In these patients it is usually common to find a personal history characterized by suffering, social isolation and misfortune. Also, with elements of chronic stress, trauma, sexual abuse or physical abuse.
The disorder usually begins in association with stressful life events and results in Slow sleep disturbances, fatigue, a very low painful threshold, increased sensitivity to stress, etc.
4. Coping strategies
Patients with chronic pain develop certain coping strategies to try to deal with their situation. These can affect physical and psychosocial functioning. In addition, they are tremendously relevant in determining the rehabilitation or maintenance of chronic pain.
People with high pain tolerance:
- They tend to consider it as a problem to be solved
- They give hopeful self-instructions
- Make exercise
- They are not abandoned to disability status
- They do not make pain the main focus of attention
People with a low tolerance for pain:
- The pain acts as a stimulus to start self-referential thoughts of catastrophic type
- They abandon possible confrontational responses
- They exaggerate their disability
- Convert to pain in the main attention
- Catastrophize the consequences from pain
- They get more and more sensitized, going into a learned helplessness regarding the problem
The degree of conviction that the patient has regarding their ability to undertake activities and tolerate pain is decisive. to start and persist in strategies of coping to face and overcome the pain problem.
Something to keep in mind is that in many of these disorders it can be observed that the search for medical help is more a function of psychological functioning of the patient than of the severity of the symptoms.
5. Biological factors of chronic pain
There is selective bone marrow filter which forms a door mechanism that determines what stimuli will pass to the brain. This mechanism is modulated by painful sensory afferences to the medulla and inputs of the mesencephalus and cerebral cortex. The interaction of these three inputs selects the type of stimuli that will travel to the brain.
Thus, previous experience, cognitive interpretation, personality, motivational and emotional variables, etc. they can influence through this mechanism, so that the painful experience is greater or lesser.
Let's see some data
- At physiological level, sensitization of nocioceptors can develop and a great excitability of neurons of the posterior antlers of the medulla and the reticulo-thalamic-cortical system.
- There is currently the opinion that most chronic pain problems (headaches, low back pain, fibromyalgia) they have their origin in the Central Nervous System (SNC), more than at the peripheral level.
- The origin is in the SNC, in a disturbance of pain mechanisms. Nerves and cells that do not specialize in transmitting pain are activated and begin to perform this function, neuronal restructuring occurs. Thus, these neurons specialize in pain perception.
- Also, in many of these patients, a depletion status of serotonin, CRF, ACTH, cortisol and catecholamine levels. This deficiency causes fatigue, pain, sleep and mood disorders.
- Some authors come to speculate that the chronic pain could be conceptualized as a atypical variety of depression. It is also known that there are genetically determined differences in the number and sensitivity of opioid receptors, of substance P or serotonin itself.
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