What Causes Arthritis Pain
Understand why you hurt, and learn the different types of pain.
With arthritis comes joint pain. Yet do you know why your joints hurt so much? The series of events that ultimately make you reach for your ice pack or bottle of analgesics involves a complex interaction between your brain and body.
Here’s a look inside the pain process, and how the type of pain you have determines its treatment.
The Pain Process
Though pain is never pleasant, it’s an important signal our bodies use to warn there’s something wrong. Usually, what’s wrong is that you have an injury of some kind, but in some cases what is wrong is that your body is misfiring pain signals.
When you have an injury – in the case of arthritis, an injury to your joints – the damaged tissues release chemicals that alert nearby sensory nerves. These nerves carry the message up your spinal cord to your brain. Your brain processes the message and sends a signal to your motor nerves to take action. So if you start to cut yourself while chopping tomatoes or you touch a hot pan you’ll pull away before you cause more damage.
Besides removing the source of injury, your body has other ways of managing pain. One method is to release painkilling chemicals, called endorphins. The brain also sends signals through the nerves to block additional pain messages from being received – thereby cutting off the sensation of pain.
Types of Pain
Doctors classify pain into two categories based on its duration:
Acute pain happens when you have a disease or injury. It is part of your body’s warning system. You’ll experience acute pain if you burn your hand on the stove, pull a muscle, have knee surgery or get a kidney stone. The pain may be momentary – the cut of a knife before you pull your hand away. Or, it can last for days or weeks – like a tooth that throbs until you can get to the dentist to have it filled. Some acute pain – for example an arthritis flare or gout attack – comes and goes.
Acute pain often is described as sharp, throbbing, shooting or stinging, though it can also be mild. It usually improves once the cause has been treated. Acute pain that isn’t resolved can eventually turn into chronic pain.
Chronic pain lasts for at least three months, but it can continue for many more months, and even years. Arthritis pain, migraine headaches, nerve damage, and low back pain are examples of this type of pain. Chronic pain is often described as an aching, dull, burning or throbbing.
Pain can continue long-term because there’s no treatment for your condition, or your doctor can’t find the source. Pain can also be self-perpetuating. Over time, the constant barrage of pain signals can change nerve cells in your brain and spinal cord. So even after the injury has healed or the condition has been treated, you’ll still feel the discomfort. In a sense, chronic pain becomes its own disease. This is the case with complex regional pain syndrome, fibromyalgia and other chronic pain conditions.
Pain is also divided into categories according to its source and characteristics – nociceptive and neuropathic pain being the two most prominent. It’s important to distinguish between the two types, because each is treated differently. Centralized pain is an important and complex category of pain.
Nociceptive pain is the immediate cause-effect pain you feel in the midst of an injury or illness. Nociceptors are receptors around your body that detect when there’s a threat to your body, and signal your brain to respond to that threat. Pain relievers such as NSAIDs (ibuprofen, aspirin) or opioids work well at treating nociceptive pain, because they interrupt the transmission of pain signals from nerves to your brain or from your brain back down to the location of injury.
Neuropathic pain is due to nerve damage that makes pain signals continue to fire, even after the immediate cause has been removed. Neuropathic pain can produce unusual sensations, like a tingling or electric feeling. Neuropathic pain can be especially frustrating because it doesn’t respond well to pain relieving medication. Instead, treatments target the affected nerves. One therapy for neuropathic pain, called neurostimulation, sends an electric current to the spinal cord. This creates an alternate sensation that prevents the original pain signals from reaching the brain.
Finding Pain Relief
Sometimes the source of pain – especially chronic pain – might not be immediately apparent. It can be frustrating and upsetting to live with a pain you can’t effectively address. Even though pain isn’t always curable, you and your doctor can work together to develop a comprehensive pain management plan that will bring you relief.