Pain

According to the International Association for the Study of Pain (IASP), pain is defined as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage." Despite this, pain is actually necessary because it serves an adaptive function—it is a defense mechanism of the body to identify stimuli or processes that cause harm to body structures. Furthermore, pain has significant sensory, emotional, cognitive, and social components, making it a subjective experience that is individual and unique to each person, depending on their physical and cognitive state.

Pain can be classified based on various criteria. According to its duration, it can be:

• Acute: Short-term pain, usually associated with tissue damage, disappearing as the damage heals. It is typically localized and may be accompanied by muscle spasms and a state of excitement or stress.
• Chronic: Lasts longer than three months, extending beyond the healing period of the original injury or being associated with a chronic condition. Its intensity varies significantly and is particularly influenced by psychological and environmental factors.

Based on the extent of the affected area, pain is classified as:

• Localized pain: Limited to the area affected by the stimulus.
• Radiating pain: Spreads to adjacent areas from the point of origin, usually along the corresponding nerve.
• Referred pain: Perceived in parts of the body far from the site of the original damage or injury.

According to its origin, pain is divided into:

• Nociceptive pain: Caused by the activation of pain receptors (nociceptors) in response to a stimulus.
• Somatic pain: Occurs when receptors in the skin, musculoskeletal system, or vascular system are stimulated.
• Visceral pain: Results from injury or dysfunction in internal organs. It is usually diffuse, poorly localized, and often accompanied by referred pain in other locations. It may also trigger vegetative and motor reflex responses.
• Neuropathic pain: Arises from an injury to the somatosensory system, leading to dysfunction and an abnormal, often disproportionate response to stimuli. It is considered pathological, as it serves no useful warning function.
• Central neuropathic pain: Affects the central nervous system (brain and spinal cord).
• Peripheral neuropathic pain: Affects peripheral nerves.
• Psychogenic pain: Not caused by nociceptive stimulation or neuronal damage but has a psychological origin, such as depression or hypochondria. It can also involve a disproportionate intensification of an organic pain due to psychological factors.
• Nociplastic pain: Caused by abnormal processing of pain signals without evidence of tissue damage or underlying pathology in the somatosensory system.

According to how it manifests, pain may be:

• Continuous or baseline pain: Persists throughout the day.
• Breakthrough pain: Sudden and transient episodes.
• Incidental pain: Triggered by a specific factor.
• Idiopathic pain: Spontaneous, without an identifiable cause.
• Mechanical pain: Related to activity and movement, disappears with rest.
• Inflammatory pain: Does not improve with rest and may even worsen. It is usually accompanied by redness and swelling.

Based on its intensity, pain is classified as:

• Mild pain: Does not interfere with daily activities.
• Moderate pain: Makes daily activities difficult.
• Severe pain: Disabling, interfering even with rest.

Symptoms

Pain itself is a symptom, signaling the presence of an injury or illness. However, the sensations associated with pain may vary depending on the stimulus:

• Stabbing or sharp pain
• Burning sensation
• Numbness
• Stinging
• Throbbing sensation
• Cramping
• Pressure

Causes

Pain occurs when a pain receptor is stimulated. This receptor transmits the signal in the form of electrical impulses along nerve fibers to the spinal cord. From there, the signal is relayed through the central nervous system, which sends a response back through motor nerves to the point of origin. During this process, the signal can be modulated or even inhibited, determining the nature of the pain experienced.

There are numerous possible causes of pain. Some of the most common types of pain and their causes include:

• Muscle and bone pain: Caused by injuries, fractures, contractures, dislocations, malformations, or specific conditions such as low back pain, sciatica, or scoliosis.
• Joint pain: Typically due to degenerative processes.
• Abdominal pain: Resulting from digestive issues, such as appendicitis, ulcers, kidney stones, or food poisoning.
• Cancer pain: Caused by tumor invasion of bone, nerve, or vascular structures. It is often breakthrough pain.
• Neuralgic pain: Caused by nerve irritation. It is extremely intense.
• Iatrogenic pain: Resulting from medical procedures, such as chemotherapy, radiotherapy, or catheterization. Postoperative pain is a common type, which arises following surgical intervention. It is acute and temporary.
• Gynecological pain: Caused by infections, inflammation, or congenital malformations.
• Labor pain: Consists of intermittent abdominal pain related to contractions, intermittent lower back pain, and continuous lower back pain. All increase in intensity as labor progresses.

Risk Factors

Anyone can experience pain at any time, but its intensity or frequency may vary based on different factors, including:

• Pain threshold: Individual tolerance to painful stimuli.
• Age
• Physical condition
• Malformations
• Posture and movement habits
• Participation in activities that may cause injuries or falls
• Presence of diseases or disorders
• Diet
• Stress levels

Complications

In addition to the possible complications arising from the underlying cause, pain itself can lead to severe issues. Chronic high-intensity pain can be disabling and prevent a person from leading a normal life. It can also significantly affect mental health, leading to irritability, frustration, insomnia, anxiety, distress, or depression. Additionally, it can cause social withdrawal, apathy, and even suicidal thoughts. Furthermore, medical treatments for pain may have significant side effects or lead to dangerous dependence.

Prevention

Absolute prevention of pain is not possible. However, its effects can be mitigated, and risk factors can be avoided when possible:

• Maintaining a healthy lifestyle with regular exercise, a balanced diet, and proper hygiene to keep the body healthy and protected.
• Getting adequate rest and sleep.
• Moderating participation in risky activities or high-impact sports.
• Treating pain when it appears to prevent it from becoming chronic.

Which Doctor Treats Pain?

Pain is treated by anesthesiology specialists and pain management units. Additionally, specialists in the underlying condition provide targeted treatment.