People feel pain when signals travel through nerve fibers to the brain for interpretation. It is often the result of tissue damage and allows the body to react to and prevent harm.
The experience of pain is different for every person, and there are various ways to feel and describe pain. This variation can, in some cases, make it challenging to define and treat pain.
Pain can be short- or long-term and stay in one place or spread around the body.
In this article, we look at the different causes and types of pain, ways to diagnose it, and how to manage the sensation.
People feel pain when specific nerves called nociceptors detect tissue damage and transmit information about the damage along the spinal cord to the brain.
For example, touching a hot surface will send a message through a reflex arc in the spinal cord and cause an immediate contraction of the muscles. This contraction will pull the hand away from the hot surface, limiting further damage.
This reflex occurs before the message reaches the brain. Once the pain message arrives, it causes an individual to feel an unpleasant sensation — pain.
The brain’s interpretation of these signals and the efficiency of the communication channel between the nociceptors and the brain dictate how an individual experiences pain.
The brain may also release feel-good chemicals, such as dopamine, to counter the unpleasant effects of pain.
In 2011, researchers estimated that pain costs the United States between
Pain can be either
Acute pain
This type of pain is generally intense and short-lived. It is how the body alerts a person to an injury or localized tissue damage. Treating the underlying injury usually resolves acute pain.
Acute pain triggers the body’s fight-or-flight response, often resulting in faster heartbeats and breathing rates.
There are different types of acute pain:
- Somatic pain: A person feels this superficial pain on the skin or the soft tissues just below the skin.
- Visceral pain: This pain originates in the internal organs and the linings of cavities in the body.
- Referred pain: A person experiences visceral pain at a location other than the source of tissue damage. For example, people often experience shoulder pain during a heart attack.
Chronic pain
This type of pain lasts far longer than acute pain, and there is often no cure. Chronic pain can be mild or severe. It can also be continuous, such as in arthritis, or intermittent, as with a migraine episode. Intermittent pain occurs on repeated occasions but stops between flares.
The fight-or-flight reactions eventually stop in people with chronic pain, as the sympathetic nervous system that triggers these reactions adapts to the pain stimulus.
If enough cases of acute pain occur, they can create a buildup of electrical signals in the central nervous system (CNS) that overstimulate the nerve fibers.
This effect is known as “windup,” which compares the buildup of electrical signals to a wind-up toy. Winding a toy with more intensity leads to the toy running faster for longer. Chronic pain works in the same way, which is why a person may feel pain long after the event that first caused it.
Describing pain
There are other, more specialized ways of describing pain.
These include:
- Neuropathic pain: This pain occurs following injury to the peripheral nerves that connect the brain and spinal cord to the rest of the body. It can feel like electric shocks or cause tenderness, numbness, tingling, or discomfort.
- Phantom pain: Phantom pain occurs after the amputation of a limb. It refers to painful sensations that feel as though they are coming from the missing limb.
- Central pain: This type of pain often occurs due to infarction, abscesses, tumors, degeneration, or bleeding in the brain and spinal cord. Central pain is ongoing, ranging from mild to extremely severe. People with central pain report burning, aching, and pressing sensations.
Knowing how to describe pain can help a doctor provide a more specific diagnosis.
An individual’s subjective description of the pain will help the doctor make a diagnosis. There is no objective scale for identifying the type of pain, so the doctor will take a pain history.
They will ask the individual to describe:
- the character of all pains, such as burning, stinging, or stabbing
- the site, quality, and radiation of pain, meaning where a person feels the pain, what it feels like, and how far it seems to have spread
- what factors aggravate and relieve the pain
- the times at which pain occurs throughout the day
- its effect on the person’s daily function and mood
- the person’s understanding of their pain
Several systems can identify and grade pain. However, the most important factor in getting an accurate diagnosis is clear communication between the individual and their doctor.
Measuring pain
Some of the pain measures that doctors use are:
- Numerical rating scales: These measure pain on a scale of 0–10, where 0 means no pain at all, and 10 represents the worst pain imaginable. It is useful for gauging how pain levels change in response to treatment or a deteriorating condition.
- Verbal descriptor scale: This scale may help a doctor measure pain levels in children with cognitive impairments, older adults, autistic people, and those with dyslexia. Instead of using numbers, the doctor asks different descriptive questions to narrow down the type of pain.
- Faces scale: The doctor shows the person in pain a range of expressive faces from distressed to happy. Doctors mainly use this scale with children. The method has also shown effective responses in autistic people.
- Brief pain inventory: This more detailed written questionnaire can help doctors gauge the effect of a person’s pain on their mood, activity, sleep patterns, and interpersonal relationships. It also charts the timeline of the pain to detect any patterns.
- McGill Pain Questionnaire (MPQ): The MPQ encourages people to
choose words from 20 word groups to get an in-depth understanding of how the pain feels. Group 6, for example, is “tugging, pulling, wrenching,” while group 9 is “dull, sore, hurting, aching, heavy.”
Other indicators of pain
When people with cognitive impairments cannot accurately describe their pain, there can still be clear indicators. These include:
- restlessness
- crying
- moaning and groaning
- grimacing
- resistance to care
- reduced social interactions
- increased wandering
- not eating
- sleeping problems
The doctor will either treat the underlying problem, if it is treatable, or prescribe pain-relieving treatment to manage the pain.
There is a prevalent myth that Black people feel pain differently from white people. Due to this, Black Americans often receive insufficient treatment for pain compared with their white counterparts.
Racial bias in pain assessment and management is well-documented.
For instance, a
The research also showed that these misconceptions affected the medical personnel’s pain assessments and treatment recommendations. This indicates that healthcare professionals with these beliefs may not treat Black people’s pain appropriately.
Eradicating racist stereotypes and biases are crucial steps toward addressing systemic inequities in healthcare.
Read more about systemic racism in healthcare and health inequities here.