Pain is commonly referred to as “the fifth vital sign” – and without the ability to recognize and assess pain, a significant portion of medical procedures and treatments would be impossible or ineffective. But despite being one of the body’s main red flags, we don’t understand a lot about how pain works or how to measure it.
We are all familiar with pain, of course, and when we’re in the throes of it, we just want it to stop. Sometimes, the cause of pain is obvious enough. But what happens when it’s not? What’s happening in our brain or nervous system so that we feel pain, and sometimes intensely?
A recent article in Scientific American recently prompted me to re-examine what I know and what I assume about the origin of pain. Going forward when treating patients I will try to embrace the complexity of pain, considering both its emotional and physical aspects.
Where does pain originate?
First, let’s look at the “standard” explanation of pain. Whether you went to medical school or simply took advanced placement (AP) biology, pain mechanisms were probably first explained to you by noting that there are two main types of pain.
The easiest one to explain is “nociceptive pain.” This is an aching, throbbing, or sharp sensation caused by damage to a specific part of the body.
Nociceptive pain is detected by nociceptors, which are pain receptors that detect physical damage to any body tissue. This may be damage to an organ, or an external injury to the muscles, ligaments, skin, or bones.
Nociceptors can detect immediate and short-lived damage (such as a pinprick), or long-lived injuries (such as inflammation or tissue damage). Either way, damaged tissue engenders an inflammatory response, meant to help the injury heal. Nociceptors detect the inflammation and carry the message of “harm” along the nerves and into the dorsal horn (a bundle of nerves at the bottom of the spinal cord), where they eventually reach the brain and produce an uncomfortable sensation.
Usually, the more intense the harm, the more intense the pain – at least in theory. And when the harm lingers (for example, if a person’s leg is crushed by a falling refrigerator, instead of being pricked by a pin), the pain lingers, too.
The second type of pain is known as neuropathic pain, which occurs when there’s direct damage to the sensory nerve fibers (nerves that transmit sensory information from the body’s periphery to the central nervous system).
Neuropathic pain is usually caused by an ongoing chronic condition, especially one that affects your central nervous system (includes the brain and spinal cord and serves as the command center for the body), such as advanced diabetes, some vitamin deficiencies, or serious conditions like cancer or lupus. Additionally, the “phantom pain” that m develop after an amputation is also a type of neuropathic pain.
Some researchers believe that neuropathic pain signals travel along different parts of the nervous system. It can radiate to other parts or cause a “referred pain” other than the site of damage. Patients with neuropathy can also develop sensitization, which can be experienced in many ways, such as being easily overwhelmed by temperature changes, or feeling a light brush as strongly as a stab.
Why pain remains a mystery
Current pain theory leaves many gaps. It doesn’t really explain the source of idiopathic pain (pain that has no identifiable or known cause). It also doesn’t explain why immediate pain seems to stimulate different parts of the brain than those activated by sustained or chronic pain.
Why is measuring pain tricky?
Pain, when described by patients, poses challenges for physicians. Relying on a pain scale from 1 to 10 is a common practice, but discrepancies arise. Some individuals rate their pain as a “9 out of 10” but appear relatively unaffected, while others rate it as a “5 out of 10” but exhibit extreme distress. These variations raise questions about the accuracy of pain reports due to the subjective nature of pain perception.
Unfortunately, this subjectivity has adversely impacted women and minorities. Historical evidence documents instances where medical professionals have not taken pain complaints seriously, particularly from women and people of color.
As a gynecologist, I often witness this firsthand. Women are frequently told that their severe menstrual pain is “normal” or dismissed as being “dramatic,” despite having conditions like endometriosis or significant cysts.
This issue transcends doubting patients or succumbing to medical bias. Without reliable pain measurement, we cannot assess the effectiveness of our interventions.
Why does chronic pain happen?
In neuroscience, chronic pain is defined as lasting for at least three months after the initial injury. But chronic pain can linger for years.
When this happens, it can begin altering the way our nervous system works, and not to our benefit.
In some cases, chronic pain doesn’t remain at a steady level. Instead, it waxes and wanes because of peripheral sensitization: peripheral nerve endings start responding aggressively to any trigger and send much larger pain signals than usual. As a result, even non-painful stimuli can trigger an “episode” that can leave you out of commission for a few days.
But why does this happen to some people? The simple answer is we don’t know. However, researchers have put forward a couple of theories regarding this matter.
One theory suggests that some people may have a genetic predisposition to chronic pain. This could be because their brain is more adaptable and changes its neural connections more quickly based on different situations. Another theory focuses on the excitability of the nerve endings.
On the other hand, we have succeeded at seeing the pain, using a special type of MRI known as functional magnetic resonance scan (fMRI). Rather than a static image of the body’s structures, an fMRI can give us a changing picture of the parts of the body that become “active” at different times. Using fMRI images, we can see the way certain parts of the brain “work” when experiencing non-painful stimuli, when in active pain, and even when they anticipate pain or remember pain experienced in the past.
And this is where one of the most interesting facets of pain theory shows up: by “anticipating pain”, are we priming ourselves for it?
The psychological side of pain
Patients with chronic pain are sometimes told that their pain is “psychological,” a fancier way of saying “it’s all in your head.” And it’s not! However, very real pain can have a very real psychological aspect to it.
Then, we need to look at our natural fear of pain. This is partially by design: from the moment we start exploring the world as babies, we learn that some things (such as banging our toes or touching hot stoves) cause pain, and therefore we learn not to do those things. When we must face a painful procedure, it’s natural to dread it – and some will even get actively anxious about it.
But if we fear pain before it comes, we are also more likely to feel it more acutely. A Dutch study from 2012 showed that people who experience more anxiety before a surgery, or who tend to “catastrophize” the pain were more likely to feel acute pain after surgery and to feel it for longer.
This doesn’t mean that pain is something we can “turn off” through sheer force of will. But it may offer us new ways to deal with it before it becomes chronic.
How is chronic pain treated?
Unfortunately, our standard methods to treat pain assume that we know exactly what is causing it, as well as the location of the injury.
When it comes to nociceptive pain, one of the most effective methods of treatment is physical therapy. This may involve massages, a heat or ice pack, as well as the more thorough stretching and flexing routines you’d get after major orthopedic surgery.
In some cases, we can also tackle pain at the root using anti-inflammatory medication. This works particularly well for post-surgical pain, but also when dealing with recurrent pain, endometriosis or uterine fibroids. All these conditions cause inflammation, which is what is ultimately behind the sharp aches or burning sensation you experience.
If this is not enough, stronger pain medication (opiates) can also deal with the pain directly. But this gets tricky for people with chronic pain. Opioids such as Oxycontin or morphine are habit-forming and addictive. Plus, analgesia also makes you dizzy and lethargic – which can easily get in the way of your daily tasks and errands.
One of the most promising new methods to deal with chronic pain syndromes lies outside of pharmacology. Pain Reprocessing Therapy (PRT), for example, is a form of psychotherapy that seeks to change the way we think about pain, especially the threat that we perceive it to be.
A relatively recent study showed that, among patients with low back pain, PRT was more likely to be effective than a placebo or the standard combination of painkillers, physical therapy, and nerve blocks. And perhaps more importantly, PRT also lowered the anxiety, depression, and “disability days” related to pain.
Dealing with women’s pain needs a holistic approach
At my practice, I routinely see women who have been enduring regular, recurrent pain for years – as well as many others who hesitate to get a much-needed surgery, out of fear of pain.
The current state of research doesn’t allow me to offer any absolute assurances. Yes, surgery for endometriosis will likely lessen the symptoms, but in up to 20% of patients, the pain will either continue or return. And when we are looking at what this pain represents – the hours of anguish, the canceled commitments, the outbursts, the fear – it makes little sense to get too technical, and discuss ganglions, somatic injury, or success rates.
What I can offer each patient, as their physician, is a promise: that I will listen to their complaints, and that I will use every tool at my disposal to address each one. That I won’t see their well-being reduced to a “from 1 to 10” value, but instead, I will work with each to understand their priorities, their fears, and their full potential.
At the very forefront of women’s health in Los Angeles – Dr. Aliabadi
Dr. Thaïs Aliabadi routinely appears among the top OB/GYNs in the country’s physician rankings. This success was earned following years of exacting training, as well as decades of building and nurturing one-on-one relationships with every woman who comes to her practice.
We invite you to establish care with Dr. Aliabadi. Please make an appointment online or call us at (844) 863-6700.
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