Pharmacological Management of Rheumatoid Arthritis
PATHOPHYSIOLOGY OF RHEUMATOID ARTHRITIS
OVERVIEW Rheumatoid arthritis (RA) is a chronic, autoimmune disease marked by systemic inflammation of both articular (i.e. joints) and extra-articular areas (e.g. cardiopulmonary systems). RA is a progressive disease; its onset can occur at any age but peaks around 30 to 60 years old. Females are three times as likely to be diagnosed with RA compared to males, and children can also be affected, as seen in juvenile idiopathic arthritis. In total, about 1-2% of people in the United States have RA, with 80% of them testing positive for rheumatoid factors: autoantibodies produced by the immune system that are responsible for the autoimmune component of the disease. Physical therapy plays a large role in the management of RA and physical therapists (PT) should be aware of the pathophysiology of the disease and the implications of therapeutic interventions used to delay or arrest the progression to provide proper patient care.
MECHANISM OF ACTION RA is marked by periods of exacerbation and remission. During the exacerbation period, it is theorized that certain cells, such as cytokines and tumor-necrosis-factor-alpha (TNF-⍺), cause the inflammatory and destructive process that occurs in the disease. In joint capsules, these inflammatory factors are found in the pannus, an abnormal layer of granulation tissue, and prevents the synovium from providing the necessary nutrients and lubrication to the joint. As the pannus proliferates, the space within the joint diminishes, consequently leading to the disintegration of the collagen, cartilage, and other surrounding tissues found here. Synovial hyperplasia occurs, causing local swelling and joint pain. These synovial changes result in irreversible bone and joint deformity, instability, and fusion, which will further affect proper functioning of the body. Extra-articular systems are similarly affected due to the inflammatory components coursing through the circulation.
SIGNS AND SYMPTOMS RA begins insidiously; it starts with cartilage degradation, then moves to ligamentous laxity, followed by synovial expansion and erosion. The joints of the hand are affected early on but any joint can be affected, including the knee and temporomandibular joint. Morning stiffness is an iconic symptom of RA, along with fatigue, diffuse musculoskeletal pain, and even depression. As the disease progresses, joint deformities and subluxation can occur, particularly in the cervical spine (Kim, 2005). Extra-articular signs include vasculitis, anemia, myelopathy, nodulosis, scleritis, and many others.
TYPES OF DRUG THERAPY There are two primary sub classifications of drugs used in the treatment of RA; drugs that provide disease modifying therapy (DMARDs) and drugs for symptomatic treatment. DMARDs are medications taken regularly for longer periods of time independent of acute symptoms. DMARDs consist of Traditional DMARDs (DMARDs) and Biological DMARDs (bDMARDs). Symptomatic therapy is used to relieve acute pain and inflammation associated with the disease process. Non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen, and corticosteroids are the primary drugs of choice for symptomatic therapy.
Rheumatoid Arthritis is a complex and ever-changing disease with treatment options that are just as intricate. Treatment regimen is based on disease severity, location of injury, comorbidities or contraindications, cost of drug, and the need for monotherapy or a combination of drugs. Recently, there have been incredible expansions in the management of RA due to an increasing number of available drug options. The PT must be aware of the effects of each drug category in order to monitor for injurious signs and symptoms the patient may present.
NSAIDs and corticosteroids are recommended for use in the initial stages of RA for short-term and symptomatic pain relief. There are minimal side effects of NSAIDs, but signs and symptoms that may present include GI bleeding, cardiovascular issues, and dizziness. Corticosteroids are also used in the initial stage as a means of reducing disease activity in patients who are awaiting a response to DMARD therapy. Typical adverse effects of Corticosteroids include immunosuppression, which oftentimes leads to infection, the development of osteoporosis, and other metabolic conditions. DMARDs and bDMARDs are similar in that they can adversely affect the GI system, pulmonary function, blood pressure, and cause skin irritation.
Although these effects may be seemingly minor in comparison to more malignant conditions, the PT should monitor and report these symptoms as appropriate. Many of these medications may cause the patient to become frail in stature, so the PT must exercise caution during the therapy session. In addition, patient education is a significant component of care and the clinician is responsible for providing relevant treatment while remaining within the physical therapy scope of practice.
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