Ouch! Why your body hurts?
Pain is the most common reason to seek medical care. More than 10 million people in the US have pain on a daily basis. Chronic pain is the leading cause of long-term disability in the US. Pain serves an important purpose, warning you when something is wrong with your body. However, ongoing, severe pain can cause worsening health and disability, dramatically impacting one’s quality of life. We will post a series of blogs to discuss pain in the coming months. Let’s explore how we feel pain.
When you drop something on your foot or slam your finger in a drawer, you know that pain will usually follow. Did you ever wonder why you feel that pain? Pain is mysterious for most of us: how does a stubbed toe or backache translate into such an uncomfortable sensation? And why does some pain go on and on?
Our body has pain receptors everywhere, both outside and within. These receptors send electrical messages through the spinal cord to the brain. One only becomes aware of pain after the brain receives and interprets these electrical messages. In some cases, such as touching a hot surface, the body can spring into defensive action even before the brain knows what is happening. That's because pain messages that reach the spinal cord can cause an automatic reflex response, making muscles near the source of the pain contract to get away from the pain.
Pain receptors and nerve pathways differ throughout the body. Therefore, the sensation of pain differs, too, depending on where the message comes from and how it travels. At times, the source of pain is difficult to locate. For example, some people feel the pain from a heart attack in the neck or jaw. People also differ in their ability to tolerate pain and how they respond to pain medication.
When tissue damage occurs, two different signals communicate the injury to our brains, one after another. Imagine a person hits their finger with a hammer. At first, they feel a sharp pain in the finger. This immediate, acute pain in direct response to cell damage is called discriminative pain. Its signal is carried by A δ fibers nerves in the injured area through a central control center in the spinal cord to a part of the brain dedicated to comprehending pain in that region of the body. In this case, from the finger to the specific brain region receiving signals from that finger.
The exact sensation of pain depends on what sort of external factor damaged the cells. For example, thermal receptors detect temperature-related pain (e.g., a burning sensation). In the hammer example, mechanical receptors detect the extreme pressure causing cell destruction. This pain signal is protective; it promotes a specific action: for example, remove your hand from the hot stove! Or don't hit yourself with a hammer again!
Within a few seconds, the finger injury's pain will begin to feel more like a dull ache. The entire hand may feel like it's throbbing, even though only some cells in that finger are damaged. This sensation is carried as a slower-moving signal by C fiber in a different pathway. This type of pain intensifies when byproducts released from injured cells cause inflammation in the surrounding area.
In an instant, following this acute pain, the injured person will experience an emotional reaction. This reaction is generally anticipation of additional pain to come, a sense of dread about the magnitude of the injury (How bad is this? Will I need to see a doctor?), and a feeling of embarrassment or anger (Of course I hit my thumb with the stupid hammer!). This response is mediated by higher brain centers, such as the amygdala, involved in ascribing an emotional or affective, quality to pain. Although affective pain isn't directly caused by injured cells, the signal still plays an important role. Anxiety response to pain motivates us to stop doing something that is causing harm to our bodies and seeking help.
However, for people experiencing chronic pain, pain continues for long after the tissue damage has healed. It is caused by changes in nerve cell connections in the spinal cord, the central control center, and the pain often accompanied by on-going anxiety, which exacerbates the sensation.
A condition called complex regional pain syndrome is an intense form of chronic pain felt after a minor injury out of proportion with what a patient anticipates. With this syndrome and other pain conditions, an initial pain signal stimulates microglia cells in the brain and spinal cord. The microglia react by releasing inflammatory signals that then stimulate other microglia, and the feed-forward cycle continues. This likely contributes to a person's persistent sensation of pain.
We received COVID-19 vaccination injections recently. Although they were just a bit uncomfortable, we received them willingly in a safe and comfortable setting, to give us protection from this awful virus. We forgot about the discomfort by the time we got back to our cars. And it is true, that we were often surprised when we felt a twinge at the injection site when we moved our arms the next day. Now imagine a scenario where a random person on street ran up to us and jabbed our arms with a needle of the same size. We can assure you, we will not feel the same way as we felt while taking the vaccine injection. You get the drift.
A person's feelings about the source of their pain affect their perception of the experience. Though a person is likely to feel sore and uncomfortable after running a marathon, they will probably consider the experience less unpleasant than a person who experiences pain following an accident. It is because a marathon is an accomplishment and requires preparation and training. On the other hand, an accident is unplanned and unwarranted.
The experience of pain is highly individualized, and therefore, often misunderstood. You may be living with chronic pain and likely struggling to explain your pain experience to others. Or, you may be a caregiver trying to figure out how to comfort someone living with chronic pain. When it comes to chronic pain, a patient's feelings toward the sensation may affect how intensely they experience it. If they describe the pain as "punishing," "cruel," or "malicious," it can give insight into the patient's relationship with it -- for example, they may believe they deserve the pain. People who think that their lives are out of their hands are more likely to experience chronic affective pain following acute pain. On the other hand, people who have a strong internal sense of locus (generally feel in control and charge of their lives) are less likely to experience chronic pain and may experience less intense acute pain.
People experiencing chronic pain also tend to rank high on depression, anxiety, sleep interference, and anhedonia (inability to feel pleasure). The question becomes: are people with depression and anxiety predisposed to experience chronic pain? Or is living with chronic pain responsible for their sleeplessness and inability to feel pleasure? To some extent, the answer is probably both. Regardless, understanding a patient's psychological state can be helpful while making treatment decisions.
Scientists continue to unearth connections between psychology and chronic pain to help clinicians get even better at personalizing potential treatments. In the meantime, the best general approach for treating chronic pain includes a combination of medications, interventions, physical or occupational therapy, and psychological techniques, such as cognitive-behavioral therapy. Patients should keep an open mind to treatment options, engage actively in their care, and learn self-management strategies, such as improving sleep or easing stress and tension. Overcoming chronic pain is like baking a cake; first, you have to assemble all the right ingredients, mix them under ideal conditions, and wait. The longer you have a medical problem, the longer it takes to correct that, usually.
Stay tuned for more information on pain. A person in pain is like a car with four flat tires.
Pain is inevitable, but suffering is optional
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Published 1/17/2021
Dr. Amar Singh, MD, and Dr. Poonam Singh, MD, are board-certified by the American Board of Internal Medicine and American Board of Obesity Medicine. They specialize in preventing, treating, and reversing chronic diseases using an evidence-based holistic approach. They are specifically interested in weight management, hormone re-balancing, and longevity. The American College of Physicians has recognized them as Fellows, FACP, for their excellence and contributions to medicine and the broader community. They enjoy teaching, volunteering, and advocating for their patients. Their mission is to share simple, effective, and proven strategies that lead to meaningful, sustainable, and long-lasting well-being.