As a rheumatologist, I’m becoming an expert in evaluating all types of joint pain. My adult patients are wonderful at describing how their joints feel: burning, stabbing, pressure, stiffness, crushing, aching, throbbing. Children use more creative language: the joint feels like ice cream, like aliens are poking at them with needles from the inside, like bugs are crawling over them.
Pain in a joint is one of the most common reasons why patients are referred to a rheumatologist, often with the suspicion that the pain is due to arthritis. Although there are many causes of joint pain, one simple question can help to differentiate between arthritis and most of the other conditions.
Arthritis is a term that refers to inflammation of a joint. There are two basic types of arthritis: inflammatory arthritis (like rheumatoid arthritis) and osteoarthritis. It’s easy to see inflammatory arthritis: it causes joint swelling, warmth, redness, and pain. Osteoarthritis, on the other hand, does not cause much joint inflammation and usually only presents pain.
So how is one to tell the difference between all of the entities that cause joint pain? Just ask this question: “when do your symptoms occur?”
Morning symptoms are most common in inflammatory arthritis. Patients describe significant stiffness in their joints when they wake up. This is referred to as the “gelling phenomenon,” which occurs because the fluid inside the joint becomes thickened, like a gel, and makes movement difficult. Patients with inflammatory arthritis have a hard time getting out of bed; it may take them over an hour before their joints begin to feel better. This stiffness improves as they pursue different activities (when the “gel” is warmed up), but if they sit for prolonged periods of time, their symptoms will return. One of my patients with active rheumatoid arthritis tells me that in the morning, her hands feel clumsy and weak, and she finds it difficult and painful to button her blouse, open jars for breakfast, or drive to work. Her symptoms improve later in the day.
In children, who are rarely able to describe “stiffness,” it is usually the parents who first notice the symptoms of juvenile arthritis (kids get arthritis too!). Parents say that their child has a limp that is worse in the morning, and improves throughout the day. They may also notice a swollen knee or ankle. However, even with a limp and active arthritis, children usually continue to do most of their activities, including sports. I had a patient with juvenile arthritis affecting her legs, who continued to run cross-country despite active disease. She would do well in races at “home,” when she was able to warm up well before a race. However, whenever she went to an “away” race, she became stiff after the long bus ride, and as a result her speed suffered.
In contrast, osteoarthritis and diseases caused by damage to the joint, such as sprains, strains, and fractures, usually present with symptoms that are worse later in the day. Pain is exacerbated when patients are involved in activities: climbing stairs, running, walking, writing, cooking, cleaning, etc. When they sit down to rest, pain improves. In osteoarthritis, the pain is due to joint damage as a result of wear-and-tear. Osteoarthritis is the kind of arthritis that people usually talk about when they say that “Aunt Bertha had arthritis of the hips and needed a hip replacement,” or “I can’t play golf with you, Lenny, the arthritis in my back is killing me!” As you can imagine, this type of arthritis becomes more common as people age, and predominantly affects weight-bearing joints such as the knees, hips, as well as the fingers. Stiffness is not a predominant symptom in patients that have non-inflammatory causes of joint pain.
Finally, I evaluate patients that have severe pain in multiple joints “all the time.” These patients don’t have the warm, swollen joints that are seen in inflammatory arthritis. They are often young, and don’t have evidence of wear-and-tear, as seen in osteoarthritis. They weren’t involved in an accident, and they didn’t sustain strains, sprains, or fractures to multiple joints. How can they have so much pain, if all of their joints look so normal? This is a topic that we are only beginning to understand. It appears that some patients develop abnormalities in the way in which their nervous system is wired, and as a result, they experience pain due to abnormal processing of pain signals. These patients are often given the diagnosis of chronic pain syndrome or fibromyalgia. The most puzzling aspect of these conditions is that the pain is real–and often excruciating–even though the joint looks normal. Treatment for these conditions are aimed at correcting the nervous system abnormalities, not at the joint. This includes aerobic exercise, cognitive behavioral therapy, and medications that help to reduce pain sensitivity.
- Inflammatory arthritis (such as rheumatoid arthritis) usually causes joint swelling, stiffness, and pain that is worse in the morning and improves with activity.
- Osteoarthritis and other causes of joint damage (strain, sprain, fracture) present with pain that worsens with activity, and improves with rest.
- Pain amplification syndrome and fibromyalgia cause persistent pain without any visible abnormalities to the joint as a result of abnormalities in the nervous system.