By A.G Moore 12/5/2012
Zebroid Horse Hybrid at the Rothschild Zoological Museum
Photo by Sarah Hartwell
A couple of years ago I noticed a new kind of swelling at the base of my left thumb. As months passed, a couple of fingers on my right hand assumed novel contours–bends appeared where before there had been none.
At the end of that first year, my internist took some blood and tested me for a variety of inflammatory diseases, besides lupus. Her conclusion was that I had seronegative arthritis (for information about RA, see http://medind.nic.in/jac/t03/i3/jact03i3p190.pdf). My mother had rheumatoid arthritis and I have lupus, so I was somewhat cognizant of what might be involved with this diagnosis. Neither the doctor nor I contemplated changing my treatment plan. I already take low dose prednisone, on and off, for lupus, so this is probably keeping a lid on the new symptoms.
Later, in an unrelated development, I surfed the Internet for information about sulfa drugs. I had read on The Voice of Lupus Foundation website that certain sulfa drugs could be troublesome for people who have lupus. So I was on the hunt for more information. (My blog about sulfa drugs will be out in a few days). In my Internet meanderings I came across the term “rhupus”. It turns out that some people with rheumatoid arthritis had been treated with a sulfa preparation and this preparation was implicated in precipitating systemic lupus. For those people who truly had SLE and rheumatoid arthritis, a new term was coined: rhupus.
This zebroid-like (zebra + horse) blend of two rheumatological terms intrigued me. So I read on. I found out that the use of “rhupus” to describe a particular manifestation of SLE is not new. The most recent article I found about the syndrome is from the National Institutes of Health and is dated September of 2012 (http://www.ncbi.nlm.nih.gov/pubmed/23115849 ). Entitled, Rhupus: when theumatoid arthritis meets lupus, the article outlines the diagnostic criteria for this peculiar manifestation. These criteria include having positive titers of anti-sDNA (for SLE) and positive anti-CCP markers for RA. Both the SLE and RA markers are classically present in patients who have each of these diseases.
There is some question in the scientific community about whether rhupus truly exists. It appears that only a very small percent of SLE patients have the kind of joint damage evident in rheumatoid arthritis. In an October 2011 article from the Hospital for Rheumatology in Argentina, two researchers question the validity of the overlap syndrome (Rhupus: report of 4 Cases: http://www.reumatologiaclinica.org/en/rhupus-report-of-4-cases/articulo/90029266/). The authors conclude that rhupus is likely a valid diagnosis and represents a distinct overlap manifestation of SLE. The authors explain that rhupus was first described in the 1960s and that the diagnosis might be applied to between 0.01 and 2% of all SLE patients.
Given the apparent rarity of rhupus, it’s not likely that a physician will be looking for this in one of their patients. However, it is good for those of us who have SLE to know that this peculiar hybrid syndrome does exist. As is always the case, when it comes to our medical care, we must be the first line of defense and the most attentive sentries.