Confirmatory tests for possible autoimmune disease.
Dear Ask The Doctor: I went to my doctor a month ago with joint pain that started suddenly in my elbows, hips, knees and ankles. He put me on Meloxicam and did a sed rate test which came back at 40. (His office called me and said the test was negative, which seems kind of strange to me since I read that 1-20 was normal for women.) So the Meloxicam helped with pain a lot, but my ankle swelled up and stayed swollen for several weeks. Then the doctor had me come take an ANA test which came back positive. He told me I have an autoimmune disease. He thinks it's either lupus or mixed connective tissue disease. He asked if anyone else in my family has had any autoimmune disease. I told him no, that most of my family members end up dying from cancer. He and his nurse looked at each other in what seemed a little unsettling. Anyway, on Monday he had me take more tests: anti-dsDNA, CBC, CMP, and uric acid. Now the tests are back, but my doctor is on vacation so I can't talk to him about them which is driving me crazy. The lab tech said the tests all came back normal. I assume this is good, but I'm still left with lots of swelling in both knees and ankles and painful hips. My legs don't look like my legs anymore. It looks like someone screwed on someone else's legs. With the last test results coming back normal, does this rule in favor of either lupus or connective tissue disorder? Or does it rule either of them out? It bothers me see something obviously going on in my body, but not no what's causing it. Can you at least give me some guesses at what you think it might be or what I should do to find out?
Dear Patient: The diagnosis of Autoimmune disorders is a very difficult and stressful process. Although each autoimmune disease is unique, many share some of the same symptoms. And many symptoms of autoimmune diseases are the same for other types of health problems too. This makes it hard for doctors to find out if you really have an autoimmune disease, and which one it might be. But if you are having symptoms that bother you, it's important to find the cause. You can also see another doctor and look for a second or thrird opinion after you have all the results of the tests. Although each disease is distinctive, many share hallmark symptoms, such as fatigue, dizziness, and low-grade fever. For many autoimmune diseases, symptoms come and go, or can be mild sometimes and severe at others. When symptoms go away for a while, it's called remission. Flares are the sudden and severe onset of symptoms. Regarding the ESR (sed rate) , this blood test measures how many red blood cells (erythrocytes) settle at the bottom of a test tube in one hour. When inflammation is present red blood cells can stick together and fall more quickly than normal to the bottom of the tube. This test is very non-specific, a high sed rate indicates inflammation but not the cause or location. On the other hand, the ANA test is part of the lab tests panel to screen Autoimmune Disorders, and is most likely used as one of the tests to diagnose Systemic Lupus Erythematosus (SLE). The ANA test is ordered when there are symptoms and signs associated with SLE or other Auto immune Disorder such as: low-grade fever, joint pain, fatigue, unexplained rashes changing over the time. Different techniques are used to perform ANA in the lab, the most common are: ELISA and indirect immunofluorescence. The results are reported as “titer”, and when positive, with a specific immunofluorescence pattern. In the case that you described, titers of 1:320 and more are considered positive, with a Centromere pattern, which means peripheral, may be associated with Scleroderma and CREST (calcinosis, Raynaud’s syndrome, Esophageal dysmotility, Sclerodactyly, Telangiectasia). Persons with scleroderma have ANA positive in about 60%-90%. In persons only with Raynaud’s disease, Rheumatoid arthritis, dermatomyosits, polimyositis, mixed connective tissue diseases a positive result of ANA may seen too. ANA can be found in persons with infections(mononucleosis), cancer, lung diseases and in approximately 5% of the normal population. As you can see the test is just one piece of information that should be interpreted along with the clinical symptoms and other tests. ANA results may be affected also by age and some medications.