Diseases > Sjögren’s Syndrome (SS) > What is it?
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What is Sjögren’s syndrome?
Sjögren’s syndrome is a chronic (long-term) rheumatic disease that is named after a Swedish doctor who first discovered it. The condition is caused when the body’s immune system gets confused and begins attacking itself. The most common place it attacks is the glands. The glands are small organs in the body that are responsible for producing a variety of body fluids. The most common glands that are affected by Sjögren’s syndrome are the tear glands and salivary glands. That’s why people with Sjögren’s syndrome often have dry eyes that feel gritty. This dryness usually gets worse as the day goes on. Other glands and other types of connective tissue can also be affected in people with Sjögren’s syndrome.
What causes Sjögren’s syndrome?
Sjögren’s syndrome occurs when the body’s immune system begins to attack its own glands. Another way to look at it is that the immune system is always turned on. Think of it like having the flu all of the time. With the flu the immune system is turned on and this makes you feel tired and achy. The same thing happens with Sjögren’s Syndrome.
The problem is we don’t know why the immune is turned on in people with Sjögren’s syndrome. What we do know is that the immune system makes too much of a type of white blood cell called B lymphocytes. These B lymphocytes make lots and lots of antibodies that can play a role in causing the symptoms of Sjögren’s syndrome.
Who gets Sjögren’s syndrome?
Sjögren’s syndrome is estimated to affect about 0.5% of the population. That means about 1 in every 200 people has Sjögren’s syndrome. So, if you live in a city with 100,000 people, then you could expect about 500 people to have Sjögren’s syndrome. It is about 10 times more common in women than in men. Tennis star Venus Williams recently put a famous face to this relatively unknown condition. People usually notice the first signs of Sjögren’s syndrome between when they are between 30 and 50 years of age.
How is Sjögren’s syndrome diagnosed?
To properly diagnose Sjögren’s syndrome you need to be seen by a rheumatologist or other specialist who knows about the disease. Sjögren’s can be tricky to diagnose and having someone experienced is very useful.
The first thing that should happen is the specialist should take a very thorough history. They should ask you lots and lots of questions because Sjögren’s can have so many symptoms. Following this, a complete physical examination should be performed including your head and neck looking for dry eyes and mouth, lungs, heart, abdomen, joints, and skin. Tests for dry eyes may include a Schirmer test. Your doctor may also recommend a biopsy of a salivary gland in the mouth. This involves taking a very small piece of tissue so that it can be examined.
Finally, special blood tests are ordered to see if your body is making antibodies to itself.
What tests are done to diagnose Sjögren’s syndrome?
Anti-Nuclear Antibody (ANA) Test
The most important blood test to do first if someone thinks you have Sjögren’s syndrome is the anti-nuclear antibody test (this is also known as the ANA). This test looks to see if your body is making antibodies to itself. Now, believe it or not, we all make antibodies to ourselves. It’s normal to do this but you don’t want to make too many antibodies or have them attacking in unusual places. The ANA test gives two results: (a) the titre and (b) the pattern.
(a) The Titre: The titre tells you how many antibodies you have. It starts out at 1:40 and then increases through the following levels 1:80, 1:160, 1:320, 1:640, 1:1280, 1:2560. In most labs the highest level is 1:2560. If your levels are 1:40-1:160 these are pretty low and might actually be normal. The level of 1:320 is the “cusp” which is more likely to mean something. Levels of 1:640, 1:1280, and 1:2560 are more concerning. Ask your doctor what your titre is. An important point: It isn’t that useful to keep measuring the titre as it does not go up and down as your disease gets better or worse.
(b) The Pattern: There are a number of patterns to the ANA including homogenous, speckled, nucleolar, centromere, rim enhancing. Homogenous is the most common and least concerning pattern.
It is fairly safe to say that if your ANA is negative then you are much less likely to have Sjögren’s syndrome.
If the ANA is positive then other tests are done. Think of it like this – looking for ANA is like looking for fish in a lake. Lets say we take a trip down to the lake, jump in our boat, and grab our handy fish finder. Lets say we go all over the lake looking everywhere for fish. There are a few possibilities: (1) We only see a few fish or none at all or (2) we see loads of fish. Ok, if we don’t see any fish then chances are if we keep going down to the lake looking for fish every weekend we aren’t going to find tons of fish. So if the ANA is negative (we don’t see fish) it isn’t necessary to keep testing it. If it is only low positive 1:40, 1:80, 1:160 don’t keep testing it. In fact, you really don’t have to ever keep testing the level (titre) of the ANA (as said above)
On the other hand, lets say we see loads of fish. The first question to ask is what type of fish are they? Are they minnows or sharks or pirrhana? Same thing with the ANA – if we see loads of autoantibodies the next question to ask is what type of antibodies they are? So if the ANA is really positive (1:320, 1:640, 1:1280, 1:2560) then you need to look at what type of antibodies they are. With Sjögren’s the common tests to look for other antibodies
Extractable Nuclear Antigen (ENA) Panel
This is a test that measures antibodies to 6 or 7 other proteins in the body. The important antibodies in this panel for Sjögren’s syndrome includes the anti-Ro (also called anti-SSA) and the anti-La (also called anti-SSB) antibodies. Things get a bit more tricky here and its best to discuss this with your rheumatologist.
The total level of all of your antibodies (immunoglobulins) can also be measured. Typically this is high in people with Sjögren’s syndrome. The reason is with Sjögren’s syndrome there a lots of B lymphocytes (B cells) around. These B cells make the immunoglobulins. So, if there are lots of B cells then one would expect there to be lots of immunoglobulins.
Read more – What is it going to do to me?