Acute pain is considered a normal, physiological and predictable response of the body to a chemical, physical or traumatic attack. Therefore, acute pain persists during the process of healing or scarring of the tissues. In this sense, pain lasting more than 3 or 6 months can be considered chronic. Bonica proposes to speak of acute and chronic pain based on the duration and the amount of underlying pathology so that short-term processes with a lot of underlying pathologies would coincide with acute pain, and painful methods of longer-term and less underlying pathology would be framed as chronic pain.
Acute pain is a fundamental element for the survival of the organism. It constitutes a first-order alarm system and warns or warns that there is some danger to the integrity of the organism that deserves attention, allowing the activation of avoidance or protection mechanisms.
characteristics of acute pain
- It is secondary to actual or potential tissue injury.
- It constitutes a first-order alarm system.
- Its time course runs parallel to the repair process.
- The scar tissue disappears.
- It is a symptom of a disease.
It is the one that persists for more than 3 to 6 months from the moment of tissue aggression. Among the characteristics of chronic pain, we can highlight the following.
Types of pain according to pathophysiology:
Nociceptive pain results from activity in neural pathways secondary to actual stimuli or stimuli that could potentially damage tissue. Nociceptive pain is the most common form of chronic pain, encompassing osteoarthritis and most forms of spinal pain.
Somatic pain originates from nociceptive information from any tissue that constitutes the body’s structure. These tissues are bones, muscles, joints, ligaments and tendons of the spine, trunk and extremities. Technically, it would also include pain mediated by the nociceptive system from the skull, the meninges that cover the brain and bone marrow, and the teeth. More explicitly, somatic pain includes all pain originating from non-visceral structures in the body. Pain from the skull is included as headache and pain from the teeth as dental pain. Therefore, when we speak of bodily pain, we refer to all those musculoskeletal structures of the thoracic and abdominal wall, the spine and the extremities.
Visceral pain comes from internal organs such as the heart and great vessels, lungs and respiratory tract, digestive system, liver, gallbladder, urological organs such as kidneys and excretory tract, and the reproductive system. Traditionally, bodily pain is understood as a form of protection for the organism; however, in the case of visceral pain, its contribution to the safety of the individual is less clear. Some internal organs are insensitive to pain. On other occasions, pain in the viscera, such as the liver, appears when a very significant and extensive injury can compromise life. Therefore, it is already too late to adopt curative measures.
Visceral pain meets five clinical characteristics.
First of all, it should be noted that not all viscera are capable of generating pain, the liver, kidneys, lung parenchyma, and most solid viscera are incapable of generating painful sensations.
It is not always associated with noxious or aggressive stimuli. For example, some harmful stimuli, such as cuts or burns, may not cause pain, and non-injurious stimuli, such as strain, may be painful.
Visceral pain is characterised by being diffuse and poorly localised.
It is accompanied by referred pain in other locations.
It is capable of triggering vegetative and motor reflex responses.
Neuropathic pain is defined as pain that appears as a direct consequence of an injury or disease that affects the somatosensory system.
Neuropathic pain is a clinical description that requires the presence of a demonstrable disease or injury that meets neurological diagnostic criteria. Signs and symptoms alone do not justify the term neuropathic pain.
When a disease or injury occurs in the somatosensory system, a series of changes are initiated in the pain conduction system that acts as pain amplifiers. Among the mechanisms involved in neuropathic pain, the following are known.
- Ectopic activity.
- Peripheral sensitisation.
- Core sensitisation.
- It decreased inhibitory modulation.
- Activation of microglia.
- Depending on the location of the lesion in the nervous system, we will speak of central or peripheral neuropathic pain.
Thenociplastic pain arises from abnormal processing of pain signals without clear evidence of tissue damage or discrete pathology involving the somatosensory system. Previously known as functional pain syndromes, these conditions include pain states such as fibromyalgia, irritable bowel syndrome, and possibly nonspecific back pain.
Types of pain according to the aetiology:
Cancer pain is a complex symptom that changes over time and results from several pain mechanisms. It encompasses various sites’ inflammatory, neuropathic, ischemic, and compressive mechanisms.
- The disease itself by invasion and compression of structures.
- The treatments applied for the oncological process: are surgery, chemotherapy and radiotherapy.
- The effects of the disease such as ulcers and weakness.
- Other comorbidities are often related to age.
- Cancer pain, in turn, can be acute or chronic. In addition to the disease itself, other factors can influence the perception of cancer pain, such as 1 :
- The emotional component includes anxiety and depression.
- The cognitive component implies the patient’s confidence in their ability to manage pain, catastrophising or hopelessness.
- The social component includes the patient’s support from his environment.
- Another factor to take into account in the case of cancer pain is the presence of breakthrough pain. Breakthrough pain is considered a recrudescence of pain superimposed on a stable baseline pain pattern in patients treated with significant opiates. Breakthrough pain may be secondary to recognisable causes such as walking or coughing, especially in the presence of bone metastases.
It is also called non-malignant or benign pain and includes all pain that is not secondary to an oncological process or its treatments.
Types of pain according to the affected system:
Depending on the affected system, we can find different types of pain: that which affects the nervous system, the respiratory and cardiovascular system, the musculoskeletal system, the cutaneous and subcutaneous system, the gastrointestinal system and the genitourinary system. The most common are those that affect the nervous and musculoskeletal systems.
If the nervous system is involved, central or peripheral neuropathic pain may occur.
Musculoskeletal pain affects the skeleton, joints and surrounding parts. Within musculoskeletal pain, we can speak of acute or chronic pain depending on its duration, nociceptive or mixed pain depending on the pathophysiology, and joint, myofascial or tendon pain, depending on the structure that generates pain.
The importance of musculoskeletal pain, apart from the fact that it is the one we see most frequently in pain units, is its enormous socioeconomic impact. Indeed, musculoskeletal pain poses an economic burden that ranks right behind the burden of cardiovascular disease.
Types of pain according to intensity:
When we classify pain based on its intensity, we must be aware that we are establishing ourselves on the information provided by the patient and that this is always subjective.
Level of pain :
- Other types of pain:
- back pain
- rheumatological pain
- traumatological pain
- cancer pain
- neuropathic pain
- gynecological pain
- abdominal pain
- postoperative pain
- headaches and migraines