DEAR DR. DONOHUE: My doctor thinks I might have rheumatoid arthritis. He wants to start treatment quickly. Why the rush? How is the diagnosis made? My mother had it and took aspirin. I can wait to take that drug. – M.W.

ANSWER: Prompt treatment of rheumatoid arthritis with today’s drugs lessens damage done to joints by this illness. That’s the reason for the rush.

Rheumatoid arthritis is the less common kind of arthritis, and it’s not limited to joints. It’s a systemic illness. That means many body functions are affected. People with rheumatoid arthritis suffer great fatigue, often lose an alarming amount of weight and are prone to infections.

Doctors have seven criteria for judging if a person has this illness. Morning stiffness that lasts more than one hour is one of them. Involvement of the joints of the wrists, hands and fingers is another. If the same joint on both the right and left side is affected, that’s another sign of rheumatoid arthritis. Most people with this kind of arthritis have at least three involved joints. Many can develop bumps beneath the skin – rheumatoid nodules. Most patients have blood tests positive for the condition. The blood tests indicate that the immune system is acting up. X-rays of the joints that show typical changes are other evidence of this kind of arthritis.

Your mother lived at a time when there were few rheumatoid-arthritis medicines. Now there are many. The beauty of the new ones is that they not only relieve joint pain and swelling, but they can stop the inflammation that destroys joints.

I won’t bore you with the names of all available medicines, but I’ll give you some of the newer ones: Rheumatrex, Arava, Enbrel, Remicade, Humira and Kineret.

DEAR DR. DONOHUE: I have diabetes, and I have to check my sugar regularly. What I don’t understand is what is normal and what is considered too low. – L.T.

ANSWER: The last time I answered this question, I earned the wrath of a diabetes doctor because I didn’t tell readers there are two ways of expressing blood sugar (glucose) values. One is the plasma glucose level, and the other is whole-blood glucose levels. Plasma is the liquid part of blood – blood without any blood cells. Plasma glucose levels are 10 percent to 15 percent higher than whole-blood glucose levels.

The control goal before a meal, expressed as plasma glucose, is 90 to 130 mg/dL (5 to 7.2 mmol/L). The before-bedtime reading should be 110 to 155 (6.1 to 8.6).

If the reading is done on whole blood, then the before-meal readings should be 80 to 120 (4.5 to 6.7), and the before-bedtime reading should be 100 to 140 (5.6 to 7.8).

When blood sugar falls to around 50 to 60 (2.8 to 3.3), people begin to sweat, feel faint and are often sick to their stomach.

There’s another way to follow blood-sugar control. It’s a blood test, done in the laboratory, called hemoglobin A1C – abbreviated as HbA1C. It indicates how well blood sugar has been controlled over the past two to three months. A reading of 6.5 percent is acceptable. Some allow it to be 7.

The diabetes booklet answers most questions on this common disorder. Readers can order a copy by writing: Dr. Donohue – No. 402, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.