| Rheumatoid arthritis (RA) is the most common | | | | "seronegative" types of arthritis. The term |
| form of inflammatory arthritis and affects more | | | | 'seronegative' means that testing for rheumatoid |
| than 2 million Americans. The diagnosis is not easy | | | | factor is negative. Symptoms of adult SAs |
| to make in many instances. There are more than | | | | include:o Back and/or joint pain;o Morning |
| 100 different kinds of arthritis. Most of them | | | | stiffness;o Tenderness near bones;o Sores on the |
| involve inflammation. When a patient goes to a | | | | skin;o Inflammation of the joints on both sides of |
| rheumatologist to get a diagnosis, there is a | | | | the body;o Skin or mouth ulcers;o Rash on the |
| process of elimination in order to arrive at the | | | | bottom of the feet; ando Eye inflammation. |
| proper diagnosis. This process of elimination is | | | | Occasionally, arthritis similar to that seen in RA |
| called "differential diagnosis." | | | | can be present. Careful history and physical |
| Differential diagnosis can be a difficult undertaking | | | | examination can often distinguish between these |
| because so many forms of arthritis, particularly | | | | conditions, especially if an obvious disease that is |
| inflammatory forms of arthritis look alike. | | | | promoting inflammation is present (psoriasis, |
| Generally it is helpful to divide the differential | | | | inflammatory bowel disease, etc.). In addition, RA |
| diagnosis of rheumatoid arthritis into two groups. | | | | rarely affects the DIP joints- the last row of |
| The first group are the non-infectious diseases to | | | | finger joints. If these joints are involved with |
| consider and the second group are the | | | | inflammatory arthritis, the diagnosis of an SA is |
| infection-related conditions. | | | | possible. (Note of caution: a condition known as |
| Since the discussion is rather long I have chosen | | | | inflammatory erosive nodal osteoarthritis can also |
| to divide the article into two parts. | | | | affect the DIP joints). RF and anti-CCP antibodies |
| The following is a partial list of forms of | | | | are negative in SAs, although, rarely, in cases of |
| inflammatory arthritis that can be seen and must | | | | psoriatic arthritis there may be elevations of RF |
| be considered when evaluating a patient with | | | | and anti-CCP antibodies. |
| inflammatory symptoms of arthritis and are not | | | | Gout is caused by deposits of monosodium urate |
| infection related. | | | | (uric acid) crystals into a joint. Gouty arthritis is |
| RA is an autoimmune chronic inflammatory | | | | acute in onset, very painful, with signs of |
| disease, primarily involving the peripheral joints | | | | significant inflammation on exam (red, warm, |
| (hands, wrists, elbows, shoulders, hips, knees, | | | | swollen joints). Gout can affect almost any joint in |
| ankles, and feet). It can also affect non joint | | | | the body, but typically affects cooler areas |
| structures such as the lung, eye, skin, and | | | | including the toes, feet, ankles, knees, and hands. |
| cardiovascular system. | | | | Diagnosis is made by drawing fluid from an |
| RA may start slowly with nonspecific symptoms, | | | | inflamed joint and analyzing the fluid. |
| including fatigue, malaise (feeling "blah"), appetite | | | | Demonstrating monosodium urate crystals in the |
| loss, low-grade fever, weight loss, and vague joint | | | | joint fluid is diagnostic, although finding elevated |
| pains, or it may have an explosive onset with | | | | serum levels of uric acid can also be helpful. |
| inflammation involving multiple joints. The joint | | | | In most cases, gout is an acute single joint |
| symptoms usually occur bilaterally- both sides of | | | | disease that is easy to distinguish from RA. |
| the body equally involved- and symmetric. | | | | However, in some cases, chronic erosive joint |
| Erosions- damage to the joint- can be seen with | | | | inflammation where multiple joints are involved |
| x-ray. In about 80% of cases, elevated levels of | | | | can develop. And, in cases where tophi (deposits |
| rheumatoid factor (RF) or anti-cyclic citrullinated | | | | of uric acid) are present, it can be difficult to |
| antibodies (anti-CCP) are present in the blood. | | | | distinguish from erosive RA. However, crystal |
| There appears to be a correlation between the | | | | analysis of joints or tophi and blood tests should |
| presence of anti-CCP antibodies and erosions. | | | | be helpful in distinguishing gout from RA. |
| Juvenile rheumatoid arthritis (JRA) occurs in | | | | Calcium pyrophosphate deposition disease (CPPD), |
| children under the age of 16. Three forms of JRA | | | | also known as pseudogout, is a disease is caused |
| exist, including oligoarticular (1-4 joints), | | | | by deposits of calcium pyrophosphate dihydrate |
| polyarticular (more than 4 joints), and | | | | crystals in a joint. The presence of these crystals |
| systemic-onset or Still's disease. The latter | | | | in the joints leads to significant inflammation. |
| condition is associated with systemic symptoms -- | | | | Establishing the diagnosis includes using:o Detailed |
| including fever and rash in addition to joint disease. | | | | medical history;o Withdrawing fluid from a joint to |
| Polyarticular JRA has similar characteristics to adult | | | | check for crystals;o Joint x-rays to show crystals |
| RA. It causes about 30% of cases of JRA. Most | | | | deposition in the cartilage (chondrocalcinosis); ando |
| children with polyarticular JRA are negative for RF | | | | Blood tests to rule out other diseases (e.g., RA or |
| and their prognosis is usually good. | | | | osteoarthritis). |
| Approximately 20% of polyarticular JRA patients | | | | In most cases, CPPD arthritis presents with single |
| have elevated RF, and these patients are at risk | | | | joint inflammation. In some cases, CPPD disease |
| for chronic, progressive joint damage. | | | | can present with chronic symmetric multiple joint |
| Eye involvement in the form of inflammation- | | | | erosive arthritis similar to RA. RA and CPPD |
| called uveitis- is a common finding in oligoarticular | | | | disease can usually be told apart by joint |
| JRA, especially in patients who are positive for | | | | aspiration demonstrating calcium pyrophosphate |
| anti-nuclear antibody (ANA), a blood test that is | | | | crystals, and by blood tests, including RF and |
| often used to screen for autoimmune disease. | | | | anti-CCP antibodies, which are usually negative in |
| Uveitis may not cause symptoms so careful | | | | CCPD arthritis. A complicating feature is that RA |
| screening should be performed in these patients. | | | | and CPPD can coexist! |
| SLE is an inflammatory, chronic, autoimmune | | | | Sarcoidosis is an inflammatory joint disorder. The |
| disorder that can involve the skin, joints, kidneys, | | | | majority of patients with this disease have lung |
| central nervous system, and blood vessel walls. | | | | disease, with eye and skin disease being the next |
| Patients may present with 1 or more of the | | | | most frequent signs of disease. Although the |
| following: butterfly-shaped rash on the face, | | | | diagnosis of sarcoidosis can be made on clinical |
| affecting the cheeks; rash on other parts of the | | | | and x-ray presentation alone, sometimes the use |
| body; sensitivity to sunlight; mouth sores; joint | | | | of tissue biopsy with the demonstration of |
| inflammation; fluid around the lungs, heart, or | | | | "noncaseating granulomas" is necessary for |
| other organs; kidney abnormalities; low white | | | | diagnosis. |
| blood cell count, low red blood cell count, or low | | | | Arthritis is present in 15% of patients with |
| platelet count; nerve or brain inflammation; | | | | sarcoidosis, and in rare cases can be the only sign |
| positive results of a blood test for ANA; positive | | | | of disease. In acute sarcoid arthritis, joint disease |
| results of a blood test for antibodies to | | | | is usually of rapid onset. It is symmetric involving |
| double-stranded DNA or other antibodies. | | | | the ankles, although knees, wrists, and hands can |
| Patients with lupus can have significant | | | | be involved. In most cases of acute disease, lung |
| inflammatory arthritis. As a result, lupus can be | | | | and skin disease are also present. Chronic sarcoid |
| difficult to distinguish from RA, especially if other | | | | arthritis can be difficult to distinguish from RA. |
| features of lupus are not present. Clues that | | | | Although RA-specific blood tests, such as RF and |
| favor a diagnosis of RA over lupus in a patient | | | | anti-CCP antibodies, can be helpful in distinguishing |
| presenting with arthritis affecting multiple joints | | | | RA from sarcoidosis, in some cases a biopsy of |
| include lack of lupus features, erosions (joint | | | | joint tissue may be required for diagnosis. |
| damage) seen on x-rays, and elevations of RF | | | | Polymyalgia Rheumatica (PMR) is a disease that |
| and anti-CCP antibodies. | | | | leads to inflammation of tendons, muscles, |
| Polymyositis (PM) and dermatomyositis (DM) are | | | | ligaments, and tissues around the joints. It |
| types of inflammatory muscle disease. These | | | | presents with large muscle pain, aching, morning |
| conditions typically present with bilateral (both | | | | stiffness, fatigue, and in some cases, fever. It can |
| sides involved) large muscle weakness. In the | | | | be associated with temporal arteritis (TA), also |
| case of DM, rash is present. Diagnosis consists of | | | | known as giant-cell arteritis, which is a related but |
| finding the following: elevation of muscle enzyme | | | | more serious condition in which inflammation of |
| levels in the blood [the two enzymes that are | | | | large blood vessels can lead to blindness and |
| measured are creatine kinase (CPK) and aldolase], | | | | aneurysms. Also, a peculiar syndrome where use |
| signs and symptoms, electromyograph (EMG)- an | | | | of the arms and legs leads to cramping because |
| electrical test- alteration, and a positive muscle | | | | of insufficient blood flow (limb claudication) can |
| biopsy. | | | | occur. PMR is diagnosed when the clinical picture is |
| In addition, in many cases abnormal antibodies | | | | present along with elevated markers of |
| specific for inflammatory muscle disease can be | | | | inflammation (ESR and/or CRP). If temporal |
| elevated. | | | | arteritis is suspected (headache, vision changes, |
| In both PM and DM, inflammatory arthritis can be | | | | limb claudication), biopsy of a temporal artery |
| present and can look like RA. Both inflammatory | | | | may be necessary to demonstrate inflammation |
| muscle disease and RA can affect the lungs. In | | | | of blood vessels. |
| RA, muscle function will usually be normal. Also, in | | | | PMR and TA can present with symmetric |
| PM and DM, erosive joint disease is unlikely. RF | | | | inflammatory arthritis similar to RA. These |
| and anti-CCP antibodies are typically elevated in | | | | diseases can usually be distinguished by blood |
| RA but not PM or DM. | | | | testing. In addition, headaches, vision changes, and |
| SAs -- psoriatic arthritis, reactive arthritis, | | | | large muscle pain are uncommon in RA, and if |
| ankylosing spondylitis, and enteropathic arthritis -- | | | | these are present, PMR and/or TA should be |
| are a category of diseases that cause systemic | | | | considered. |
| inflammation, and preferentially attack parts of | | | | In part 2 of this article, I will discuss infectious |
| the spine and other joints where tendons attach | | | | diseases that need to be considered in the |
| to bones. They also can cause pain and stiffness | | | | differential diagnosis of rheumatoid arthritis. When |
| in the neck, upper and lower back, tendonitis, | | | | RA is suspected, it is critical to consult with an |
| bursitis, heel pain, and fatigue. They are termed | | | | expert rheumatologist. |