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To Your Good Health: Sensitivity to Gluten Causes Celiac Disease

Dear Dr. Roach: I have several symptoms of gluten intolerance. I’ve read that there are tests to confirm celiac disease. Besides a blood test, one test is a biopsy of tissue taken from the small intestine. How does the doctor retrieve such tissue? How reliable are the results of these tests after following a gluten-free diet? — S.S.

Answer: Celiac disease, also called celiac sprue, is caused by a sensitivity to gliadin, a component of gluten, which is found in wheat, barley, rye and oats. The major symptoms are weight loss, diarrhea and abdominal distention and bloating. The diagnosis is usually made based on a combination of blood tests and a small-intestine biopsy, which is obtained via an endoscopy of the stomach and intestine.

Neither the blood tests nor the biopsy is perfect. In people who have been on a strict gluten-free diet, it is possible the antibody blood test and the biopsy return as normal. In this case, a blood test to determine genetic risk for celiac disease can be done, and if that is negative, then celiac disease is excluded. If the test is positive, many experts recommend a diet WITH gluten followed by repeat endoscopy and biopsy, although some people might prefer just to stay on their gluten-free diet.

After a biopsy shows the characteristic changes, the diagnosis of celiac sprue is confirmed when symptoms go away with a gluten-free diet. It is not necessary to rebiopsy to show that the intestinal changes return to normal.

Hello, Dr. Roach: I was diagnosed with stage III kidney disease in May 2012. I had been taking HCT for more than 10 years for hypertension; apparently it did not control my blood pressure well enough to ward off kidney damage. I have been prescribed Azor once a day. After taking it with the HCT for two weeks, my GFR (glomerular filtration rate) went down 10 points, although my BP is much better, usually less than 120/80. The drastic change in my GFR concerns me greatly. Is this medication worse than the illness? A few years ago, Vioxx was taken off the market because it caused damage and fatal results in some patients. Is this a similar medication? I would appreciate any advice you can give me. — P.E.D.

Answer: This gets a little confusing, so bear with me. Azor is a combination of two medicines: amlodipine and olmesartan. Olmesartan is in the class of ARBs (angiotensin receptor blockers, which work by opening up constricted blood vessels), and these have the effect of reducing blood flow to the kidneys. GFR (glomerular filtration rate) is a measure of kidney function, and is directly related to the blood flow to the kidneys. So a medicine like olmesartan — or any of the ARBs or ACE inhibitors — will very often drop GFR. A lower GFR means a higher creatinine level, since creatinine is removed from the blood by the kidneys. Since a higher creatinine means worse kidney function independent of the medication effect, it’s natural for patients to worry that the kidneys are being damaged and want to stop taking the meds.

However, it usually isn’t necessary to stop. The lower GFR actually protects the kidneys from the effect of high blood pressure. Unless the GFR goes down by 30 percent (or creatinine goes up by 30 percent), we generally don’t stop it. It sounds like the medication is working well for you.

Vioxx is not related to these medicines at all.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or write to P.O. Box 536475, Orlando, FL 32853-6475.