What is Rheumatoid Arthritis and Ankylosing Spondylitis?
Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are among the most common diseases related to joint inflammation. These long-term conditions gradually worsen over time, leading to a decrease in physical ability and an increase in the degeneration of joints. It’s interesting to note that while they share a similar kind of inflammation, their symptoms and causes are quite different.
In the past, AS was often incorrectly diagnosed as RA. However, thanks to improved techniques in diagnosis and laboratory tests, doctors now recognize these as two separate illnesses. This improved understanding is attributed to medical advancements that can distinguish between the two conditions. However, correctly diagnosing these conditions can still be difficult for doctors.
Both RA and AS have similar symptoms at presentation, characteristics visible on medical imaging, and test results related to antibodies in the blood. However, RA and AS have very distinct characteristics concerning each condition’s processes in the body and the genetic factors at play. This makes it unlikely for a patient to have both conditions, as they are quite different in their underlying causes.
However, because both diseases can show similar physical symptoms or changes visible through imaging tests, such as stiffness in the morning or in other parts of the body, diagnosing them could be challenging and might require more tests to determine the correct cause. In fact, there have been cases reported of a patient having both AS and RA, going back to 1976.
What Causes Rheumatoid Arthritis and Ankylosing Spondylitis?
Research has suggested that two conditions, rheumatoid arthritis (RA) and ankylosing spondylitis (AS), may share similar causes. This idea is backed by the fact that different genetic makeups can lead to the development of these conditions.
For example, if a person has certain genes, specifically, ‘human leukocyte antigen (HLA) HLA-DR4’ for RA and ‘HLA-B27’ for AS, and is also exposed to certain environmental factors, they may have a chance of developing both conditions at the same time.
The first instance of a person having both RA and AS was reported in 1976. Since then, less than 60 similar cases have been reported. This low number may be due to the lack of thorough medical examinations, observations, or full evaluations.
Risk Factors and Frequency for Rheumatoid Arthritis and Ankylosing Spondylitis
Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are conditions that affect between 0.3% and 1.5% of the general population. It’s interesting to note that AS is more common in men, while RA is more prevalent in women. Typically, AS starts showing symptoms before the age of 30, whereas RA often develops later in life, usually between 40 to 50 years of age.
- Approximately 90% of people with RA end up developing a condition called cervical spondylitis. This primarily involves instability in the neck area, and can present in several forms such as atlantoaxial subluxation, subaxial subluxation, and basilar invagination, with the last occurring in about 20% of RA patients.
- The prevalence of these conditions globally can vary, influenced by factors like ethnicity and the presence of human leukocyte antigen (HLA)-B27. Specifically, the prevalence of AS is around 5% to 6% among individuals who are HLA-B27-positive.
Signs and Symptoms of Rheumatoid Arthritis and Ankylosing Spondylitis
Rheumatoid arthritis (RA), a condition that mainly affects joints in the hands and feet, often starts with symmetrical inflammation. This condition typically causes stiffness that lasts for over an hour, especially in the mornings. As the illness worsens, joints can erode and result in deformed fingers and toes.
Diagnosis of RA looks for inflammation in three or more joints that’s been present for more than six weeks, positive tests for specific proteins (rheumatoid factor and anti-citrullinated peptide/protein) related to RA, and other signals of inflammation. It’s also essential to rule out other similar conditions like psoriatic arthritis, acute viral polyarthritis, polyarticular gout or calcium pyrophosphate deposition disease, and systemic lupus erythematosus. Sometimes, patients with RA can develop a condition called cervical spondylitis which may cause headaches from the compression of a nerve in the neck.
When assessing the severity of neurological impairment with RA spondylitis, doctors often use the Ranawat Classification System:
- Grade I: Subjective feelings of tingling sensations and pain
- Grade II: Subjective feelings of weakness, signs of upper motor neuron damage
- Grade III: Objective weakness, upper motor neuron findings
- IIIA: Able to walk
- IIIB: Unable to walk
There’s some debate about how to best manage patients in grade IIIB, as surgery—which can sometimes be beneficial—also carries a significant risk of complications after the operation.
Ankylosing spondylitis (AS) is another condition similar to RA. It usually affects the lower spine and the joints where the spine connects with the pelvis. Symptoms involve persistent back pain that often begins before the age of 40, with pain that tends to worsen at night or with rest but typically improves with exercise. Over time, this condition can also lead to a hunched posture due to the fusion of the spine. Some people also experience severe joint pain in the hips, knees, or shoulders. However, unlike RA, joint erosion is rare in AS.
So, both AS and non-radiographic axial spondyloarthritis, a condition that shares many symptoms with AS but doesn’t show on X-rays, are part of a group of diseases termed “axial spondyloarthritis”. These conditions have signs of inflammation in the spine and contain other shared features found in spondyloarthritis in general.
Testing for Rheumatoid Arthritis and Ankylosing Spondylitis
Ankylosing spondylitis (AS) typically occurs in younger men who carry a gene known as HLA-B27 and largely affects the sacroiliac joints, which are located where the spine meets the pelvis. On the other hand, Rheumatoid arthritis (RA) commonly affects middle-aged women, and usually impacts smaller joints in the hands and wrists.
Several tests can aid in the diagnosis of these conditions, including measurements of your erythrocyte sedimentation rate (ESR, a kind of inflammation marker), C-reactive protein (CRP another inflammation marker), rheumatoid factor (an antibody often present in patients with RA), anti-CCP antibody (another marker for RA), HLA-B27, HLA-DR2, and HLA-DR4 (all genes that can be associated with certain types of arthritis). However, note that the ESR and CRP tests may not specifically pinpoint the type of arthritis, as they only check for general inflammation in the body.
Plain x-rays are useful in diagnosing AS – they can reveal inflammation of the sacroiliac joints, a common symptom in patients with AS. More advanced imaging like MRI may display bone swelling and other subtly signs of inflammation that might not be detected through an x-ray.
It’s important to note that both AS and RA can coexist in the same patient. However, some studies suggest that AS patients who test positive for the rheumatoid factor (a marker commonly associated with RA) don’t typically exhibit the joint erosion more characteristic of RA.
Treatment Options for Rheumatoid Arthritis and Ankylosing Spondylitis
When it comes to treating both groups of patients, the approach is somewhat similar, although the goal is always to give treatment that suits each individual’s unique needs. Doctors have to consider numerous factors when deciding on the best treatment plan. These include how severe the disease is, whether there are other health problems, how well a patient is able to tolerate medication, the potential risks of side effects, patient’s expectations and other personal factors.
Nonsteroidal anti-inflammatory drugs (NSAIDs) and pain medication are usually the first course of action and can be taken for weeks or even months. Additionally, all patients would benefit from exercise and physical therapy. These can help avoid long-term stiffness, damage, and issues with joint functionality. There are also certain medications, such as methotrexate, leflunomide and sulfasalazine, that are effective in treating rheumatoid arthritis but aren’t useful for ankylosing spondylitis (AS). Anti-tumor necrosis factor agents, however, do work for AS. One type of medication, known as systemic glucocorticoids, are best avoided especially for long-term use.
Surgery options are also personalized for each patient. For instance, if a patient has significant neck pain or signs of neurological issues due to C1-C2 subluxation, a condition that occurs in people with rheumatoid arthritis but not AS, they might need a procedure called atlantoaxial joint fusion. This surgical procedure stabilizes the connection between the first two bones in the neck. In some cases, a patient may even need a joint replacement.
What else can Rheumatoid Arthritis and Ankylosing Spondylitis be?
People with axial spondyloarthritis (AS), a type of arthritis that affects the spine, can also suffer from peripheral arthritis, enthesitis, and dactylitis. These conditions can sometimes be mistaken for rheumatoid arthritis (RA), leading to a misdiagnosis.
What to expect with Rheumatoid Arthritis and Ankylosing Spondylitis
Both conditions are long-term and can be maintained for many years before they lead to life-threatening complications. Many of the symptoms can be effectively managed with medical treatments and surgeries. However, the risk of heart-related diseases is higher in both cases, likely due to the ongoing inflammation in the body.
As a result, many individuals with these conditions may experience heart problems or sadly, pass away early because of heart diseases, rather than the conditions themselves.
