What is Nociceptive Pain?

by Jenny L. F. Andrus, MD
How do you describe pain?  When I talk to my patients about pain, they may use descriptions like stinging, burning or throbbing, dull or sharp, intermittent or constant.  They may tell me to envision a cartoon where some character gets bopped over the head or smashes a finger and their affected body part pulsates with red and makes sound effects signaling severe pain. They may use terms like “angry” which conjure up emotional responses to pain.  All of these help me to understand pain as the patient feels it, which is important when seeking to relieve it effectively.
I use terms to describe pain clinically, which may be unfamiliar to the average patient.  However, these terms are important because they illustrate how the pain is generated and communicated in the body and may help indicate the cause for the pain and if it will be easily treatable.
One of the terms I use to define pain is Nociceptive.  This means that the pain is sensed by the miniature nerves that are present throughout the body, which communicate chemically with each other and with the brain.  These nerves are present in the organs, joints, muscles, ligaments, tendons and bones and play an important role in communication about the state of the body to the brain.  Cuts, bumps, bruises, sprains, strains, and fractures all can cause nociceptive pain.
Nociceptive pain is usually described as a localized, aching, sore or throbbing pain and can be caused by injury or from a disease like arthritis (which is not time-limited). These sensations are transmitted by a chemical communication between nerves in the pathways leading to the brain.  Normally, this communication lessens or ceases when the pain generator is treated, meaning the pain is time-limited.
For example, you may step on a tack and it causes pain in your foot.  In mere nanoseconds, your nerves release “alarm” chemicals that communicate the problem to the brain by traveling up the spinal cord. The brain instructs you to look at your foot and upon discovering the source of the pain, you can remove the tack and the “alarm” is turned off.   Although your foot might be sore for a day or two, those acute pain signals go away when the tack is removed.  This simple illustration shows how nociceptive pain works as an efficient protective mechanism for our body against pain.
However, in some patients, problems can develop if this “alarm communication” continues unabated for a period of time.  Pain may be sensed, even if the original pain generator has been addressed and the problem resolved.  Because these chemical signals are unable to “turn off”, they can lead to chronic pain.  An example would be a bone fracture that heals well after treatment but continues to hurt, when the anatomical or mechanical issue has been fixed correctly. The alarm continues to ring even though the immediate danger has passed.  The pain signals can be quite severe and debilitating to the patient.
I see patients regularly that suffer from chronic nociceptive pain and work to treat the pain generator.  For patients that develop chronic nociceptive pain, we try to interrupt those pain signals by a variety of treatments. For example, we can use medications, such as anti-inflammatories, injections or other procedures, such as radio frequency ablation, to treat the pain caused by over-active nociceptors.  In severe cases, opioids can be used to help provide relief.