Referred pain (reflective pain)
Referred pain, also known as reflective pain, occurs when discomfort is experienced in a location different from the actual source of the pain stimulus. This phenomenon is relatively common in various medical conditions, particularly in cases like heart attacks or osteoarthritis. The pain typically presents near the original injury site but not directly at it; for example, hip arthritis may result in knee pain.
The underlying mechanism for referred pain is believed to involve a phenomenon called convergence in the nervous system, where signals from multiple body receptors can overlap in the brain, leading to misinterpretation of the pain’s origin. Additionally, some theories suggest that inactive nerve connections may become active during episodes of pain, further complicating the sensation's localization.
Diagnosis often involves identifying the true source of pain, which may require imaging techniques or anesthetic tests to distinguish referred pain from primary pain. Understanding and treating referred pain can improve patient outcomes, as effective treatment hinges on addressing the underlying cause. Overall, the prognosis for those experiencing referred pain varies, depending significantly on the initial condition responsible for the symptoms.
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Referred pain (reflective pain)
Referred pain is discomfort that occurs in a site on the body other than the site where the painful stimulus is actually present. It is fairly common in some conditions, such as heart attacks and osteoarthritis. The pain can usually be treated by identifying the original cause of the discomfort and resolving it, although it may require some investigation to find the source of the pain. Referred pain is also known as reflective pain.
Background
Pain is the body’s warning system that something is wrong. It is an uncomfortable feeling in some part of the body that is caused when nerves respond to some form of stimulus. This stimulus can be an injury, infection, disease, or some other cause that in some way alters the body. As a result of this stimulus, pain receptors are activated and send signals through the spinal cord to the brain to alert it of the injury. The brain responds to the part of the body that sent out the signal with instructions on what to do next. This happens instantly, so that in the case of an injury a person often pulls the injured body part away from the pain source even before the person fully understands that an injury has occurred.
There are many different levels of pain, from very mild to unbearable. Pain can also be felt as a number of different types of sensations, such as stabbing, throbbing, aching, or a feeling of heat. Pain can be acute, meaning it happens related to a specific incident and subsides as healing occurs, or chronic, meaning it is long-lasting and continuous.
Pain can occur in any part of the body. It usually occurs directly at and near the location that was injured or affected by the injury or other pain stimulus. However, a person can also experience referred pain. This is pain that happens at a source other than the location of the stimulus that is responsible for the pain. It is unclear exactly why this happens, but it is believed to be the result of pain signals from deeper in the body being perceived as coming from areas closer to the surface. One of the most common examples of referred pain occurs when a patient experiencing a heart attack feels pain in the jaw or arm instead of the heart or area of the chest near the heart.
Overview
Although referred pain does not occur directly at the site of the original stimulus, it usually occurs somewhere nearby. For example, a person with arthritis in the hip may feel the pain in the knee, while someone with a source of pain in the upper back may feel as if a shoulder is injured. Referred pain that originates in the spinal cord may be felt in another place along the structure.
Referred pain is not the result of the person misinterpreting where the pain is coming from or imagining that there is pain. It is believed to be caused by a nervous system phenomenon called convergence. The nervous system has different types of receptors. These receptors are located in virtually every part of the body, including the skin, heart, lungs, bones, and teeth. Some respond to input such as touch. Others respond to more urgent input such as pain or exposure to something else dangerous, like a toxin or extremes of temperature.
The signals from all of these receptors in the other areas of the body travel to the brain. However, the signals from the receptors from multiple areas of the body can be received in the same general area of the brain. As a result, the signals can sometimes converge, or come together. This results in the brain thinking that the pain is coming from a different part of the body other than where it is really located and is known as referred pain. For example, the receptors for the chest, arm, and jaw are close to one another. This is thought to be the reason that pain from a heart attack is sometimes felt as pain in the arm or jaw.
Another possible explanation for referred pain is thought to be latent or inactive nerve connections. Some experts believe the body may have some nerve connections that are not normally used and do not usually respond to any stimulus. However, when there is prolonged stimulus, such as the ongoing pain that results from arthritis, or sudden acute pain, such as that from a heart attack, it is thought that these inactive connections get turned on and begin to work. However, because they are not part of the usual nervous system connections, the brain gets confused about their source and interprets the pain as being in another location.
Some types of referred pain are so common as to be seen as symptoms of another condition; this is why arm and jaw pain are listed as potential symptoms of a heart attack. Medical professionals who see a patient experiencing pain in one of these areas will generally automatically check the patient for a possible heart attack. Other types of referred pain are more difficult to identify. For instance, a patient with arthritis may complain of pain in the knee but not respond to treatments for pain in that area. The patient may need x-rays or other diagnostic tests to determine what area is really experiencing the discomfort so it can be treated.
Treatment for referred pain involves identifying that it is referred pain and then identifying the original source of the discomfort. In some cases, this can be done by using imaging techniques such as x-rays to identify areas that show evidence of damage or illness. Another way that physicians can determine if the pain source is in a particular area or referred is to anesthetize the area in question. For example, if a patient presents with tooth pain but the pain persists even when he or she is given an anesthetic, then the pain is likely referred from another source. The prognosis for a patient with referred pain depends on the cause of the discomfort.
Bibliography
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