A general approach to joint pain focusing on acute monoarthritis

Hello I'm Dr. Sarah Tedeschi, and thanks for joining us as we review a general approach to joint pain. Focusing specifically on Acute Monoarthritis.

Today, we'll cover the difference between arthralgia and arthritis. We'll talk about history focusing on joint pain, using the acronym No Pads. Will talk about the distribution of involved joints, and how that can help us differentiate between different types of arthritis, and then we'll go through two cases of acute monoarthritis to discuss how we think about decision-making and treatment.

Arthralgia is a synonym for joint pain. This means pain localized in or around a joint. Not necessarily involving inflammation. By contrast, arthritis tends to involve joint inflammation. So as a rheumatologists, when I see a patient who comes in complaining of diffuse joint pains or even focal joint pains. My first question to myself is whether this patient has arthralgia or arthritis, because the differential diagnosis of those conditions is quite different. Arthralgia has can be related to the joint itself or to structures that are around the joint. What structure should we consider that are around the joint? First I consider the Bursae which are physiologic fluid collections that act as a buffer between tendons and joints themselves, and they help to provide some lubrication during normal joint movement. But, these bursae can become inflamed. So for example, a patient who has shoulder pain, that's pinpoint localized right below the acromion process, might have subacromial bursitis as a cause of shoulder pain. Tendons are also right around the joints, and they are the structures that connect muscles to bones and they act like pulleys. Because they act like pulleys, they're often subjected to friction, and so tendons can become irritated again quite often in the rotator cuff of the shoulder, and so patients can present with shoulder pain are even pain localizing around the deltoid muscle, that's from rotator cuff tendonitis. When tendonitis becomes severe, or in the case of acute trauma, a tendon can actually rupture entirely, and that can also produce pain. Of course bones are in and around joints and focal problems of the bone can manifest his joint pain. For example a patient who has a femur fracture could manifest with knee pain. Avascular necrosis can also present with focal pain of the joint for example in a patient who has been taking long-term glucocorticoids who has sudden onset groin pain. They may actually have a avascular necrosis of the hip joint, and in a patient who has either a known diagnosis of cancer or potentially a new diagnosis, metastasis of the bone can produce focal pain. In addition to considering these structures, there are also conditions that can cause joint pain without inflammation. So again, this is thinking about arthralgia. The first is actually called an "itis" osteoarthritis. This is the most common form of joint arthritis, and it tends to increase in prevalence with age due to wear and tear of the cartilage and resulting in bone on bone contact and pain. You know the fact that it's called osteoarthritis actually makes it sound inflammatory, and in a subset of patients approximately 20 percent have synovitis on MRI exams. So in some patients with osteoarthritis, this probably is an inflammatory condition. But, in the majority of patients, we don't tend to think of it as an inflammatory problem. Overuse syndromes, for example repeated typing or texting on mobile devices can cause local pain in the wrist or fingers or a patient who is working at a job that requires repeated use of a stepping motion for example or long-term driving a truck can result in focal pain to the lower extremity joints for example. Neuropathies can cause pain especially patients who have severe neuropathy such as Charcot-Marie-Tooth syndrome which can result in a Charcot joint which is a degenerative joint problem resulting from micro traumas to the joint because of the inability to feel the slight damages or slight imbalances of the joint. Viral syndromes can cause diffuse joint pain. Think about influenza virus things that cause systemic inflammation and malaise but also some other syndromes that tends to specifically cause joint problems, for example chikungunya virus or parvovirus B19. Some medications such as aromatase inhibitors have been noted to cause diffuse joint pain in a subset of patients. Hypothyroidism can cause diffuse pains. Fibromyalgia, of course, is always on the differential diagnosis and rheumatology clinic, and patients with fibromyalgia may also have other rheumatic diseases such as rheumatoid arthritis that actually do cause joint inflammation. But if the inflammation from the rheumatoid arthritis is under control, there is certainly a possibility that patients can also develop fibromyalgia leading to joint pains even in the presence of well-controlled rheumatoid arthritis. Finally, depression is a syndrome that should be considered in a patient who has diffused pain without evidence of inflammation.