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Are There Different Types of RA?

My rheumatologist believes that I may have a combination of rheumatoid arthritis (RA) and ankylosing spondylitis (AS). I present classic symptoms of RA including joint inflammation and damage in joints commonly associated with RA, symmetrical presentation on both sides of the body, bone erosion, duration of the symptoms, positive blood tests associated with RA, and fatigue. At the same time my rheumatologist noted limited spinal mobility and many problems with my ankles and Achilles’ tendons that are common with ankylosing spondylitis. My first autoimmune symptom, which occurred years before joint problems surfaced, was inflammatory uveitis (iritis) in both eyes. An ophthalmologist immediately suspected ankylosing spondylitis and asked about my back and hip joints – which surprised me! While Achilles tendon problems and uveitis can be associated with RA, they are more commonly seen in ankylosing spondylitis patients. But a blood test for HLA-B27, a common genetic test related to ankylosing spondylitis, was negative. The official diagnosis in my medical chart has always been rheumatoid arthritis (diagnostic code 714).

Diagnosing RA is not always a straightforward process. There are many people with clinical symptoms of RA who do not have a positive blood test. Such patients may be called “seronegative” and upwards of 30% of cases are classified as such (Duskin & Eisenberg, 2010).[1] This lack of completely accurate blood tests adds fuel to the argument that there may be different types of RA.

Muddying the water is the fact that treating RA involves a slew of medications that work in varying capacities depending on the patient and treatment combination. While many RA patients find relief from the most common treatments like methotrexate, Enbrel, and Humira, they are not effective for up to 30-40% of patients (Rubbert-Roth & Finckh, 2009).[2] Personally, I have been through a slew of RA treatments, four DMARDs and seven biologics, in an effort to find a combination that works for the long term.

There are different types of inflammatory arthritis including rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis (Arthritis Research UK).[3] Even young children can get inflammatory arthritis. While it used to be called Juvenile RA, it’s now called juvenile idiopathic arthritis (JIA). There are even sub-types of JIA. And each of these diseases presents different clinical patterns and blood tests. All of these related diseases are treated with similar medications.

The scientific community agrees that RA is not a clear cut, singular disease. According to researchers from the Netherlands, “Rheumatoid arthritis (RA) is a heterogeneous disease with unknown cause“ (van der Pouw Kraan, et al., 2007).[4] These researchers found differences in the genetic expressions of RA patients lending some credence to a genetic link to sub-types of RA. In an earlier study of the genetics of RA, researchers found that a gene called HLA-DR was found in 83% of patients with classical or definite RA (Woodsworth, et al., 1989).[5] But no explanation is given for the 17% of RA patients who did not show this gene. In 2010, a group of researchers found four genetic sub-types of RA (Dennis, et al., 2010).[6] Furthermore, Japanese scientists found genetic differences in RA patients at the molecular level adding credence for subsets of the disease (Ishihara & Igarashi, 2012).[7] Some researchers even found different emotional responses in RA patients (Tillmann, et al., 2010.[8]

While the causes of RA are not completely evident, most scientists suspect a combination of factors including genetic and environmental causes. Scientists are now beginning to unravel the complexities of RA and find that there may actually be a variety of sub-types of the disease. I predict that future research into RA and other autoimmune diseases will reveal that genetics and environmental factors impact the way individuals present symptoms and respond to treatments. This knowledge may lead to definitions of RA sub-types and better treatments in the future.

 

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The RheumatoidArthritis.net team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

  1. http://onlinelibrary.wiley.com/doi/10.1111/j.0105-2896.2009.00856.x/full
  2. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2669237/
  3. http://www.arthritisresearchuk.org/arthritis-information/inflammatory-arthritis-pathway.aspx
  4. http://www.ncbi.nlm.nih.gov/pubmed/17223656
  5. http://www.ncbi.nlm.nih.gov/pubmed/2481309
  6. http://www.blackwellpublishing.com/acrmeeting/abstract.asp?MeetingID=774&id=90254
  7. http://cdn.intechopen.com/pdfs/25397/InTech-Molecular_mechanisms_of_rheumatoid_arthritis_revealed_by_categorizing_subtypes_of_fibroblast_like_synoviocytes.pdf
  8. http://arthritis-research.com/content/15/2/R45/abstract

Comments

  • Connie Rifenburg
    5 years ago

    Thanks Andrew. I always like the way you explain some otherwise scientifically challenging information. I sit back and say – “oh, so that’s what that new idea is looking at.” 😉

    I recently had my RA dr. agree that my dry eyes has reached the point beyond just ‘dry eyes’ and tested some blood work for Sjogren’s Syndrome. I see her next week for the results, but in the meantime, my opthamologist, observing the severe dryness, stated with certainty (?) that I “obviously had Sjogren’s. It will be interesting to see if the blood work confirm this additional autoimmune disease. I was told early in my RA disease that I also had many symptoms of ankylosing spondylitis, but since the treatment for most autoimmune diseases are similar for the most part, my RA dr. has not changed anything in my ongoing RA treatments.

    After getting the diagnosis of RA, and then the 2-yr major flare that took me into disability in 2009, I have generally accepted any additional symptoms as one and the same disease in my own mind. I know they have their differing modes of attack, but to me, I picture them as a black hole of pain that gets larger or smaller depending on how my body handles the symptoms. I leave the particulars to the Drs.

    It would be nice if the powers that be – in naming these new sub-sections of autoimmune disease would use a different name than Arthritis. Do other’s agree with me that using the term Arthritis confuses the issues between those that have aging/wear & tear osteo arthritis with the autoimmune disease which adds to the stress of correcting others who think you have “just arthritis”..”oh my whole family has that and we just take Advil when it hurts and it goes away.”

    By that time in the conversation, I just smile and nod. So, let’s get together and watch these new sub-categories being found and get them to remove the name Arthritis from any and all autoimmune diseases and …well… what would you like them to call it (nice words only) haha… shall we vote on this? At least we can hope eh?
    Connie

  • Tamara Haag moderator
    5 years ago

    This is very interesting, Andrew. I have had two different rheumatologists debate between a diagnosis of RA or psoriatic arthritis. I’m glad that there continue to be developments so that diagnoses and treatments will hopefully improve.

  • Andrew Lumpe, PhD moderator author
    5 years ago

    Glad you liked the article Tamara. Things do tend to blur together when it comes to autoimmune diseases.

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